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From Dave Barry’s 1999 novel Big Trouble, here’s a description of a Miami construction company named Penultimate:

Penultimate was as good at municipal corruption as it was bad at actually building things. In political circles, it was well known that Penultimate could be absolutely relied upon to do the wrong thing. In South Florida, a reputation like that is priceless.

Granted, sometimes there were problems. There was the time Penultimate won a large contract to build a prisoner-detention facility in downtown Miami. … During a bad lightning storm shortly after the facility went into service, a number of key doors simply opened themselves, leaving it up to the prisoners to decide, on the honor system, whether they wished to remain in jail. … The highlight came when the capture of an escaped prisoner was shown live, nationally, on the NBC Nightly News. A reporter shouted to the prisoner, as he was being hustled into a police cruiser, “Who masterminded the escape?”

“Ain’t nobody masterminded shit,” the prisoner shouted back. “The mufuh doors opened.”

Even by Miami standards, this was considered a major screwup. Under intense pressure from the media, Penultimate explained, through its dense firewall of high-priced attorneys, that all the blame belonged to … subcontractors. The politicians, who did not want Penultimate to get into trouble, inasmuch as almost all of them had received money from the company, pounced on this explanation like wild dogs on a pork chop: Yes! That was it! Subcontractors were responsible!

Unfortunately for the cause of justice, most of the key subcontractors involved either fled the country or died, generally in boating accidents. Eventually, the investigation lost steam, and the issue degenerated into a vast steaming bog of lawsuits and counter-lawsuits that would not be settled within the current geological era. Everybody lost interest, and Penultimate went back to winning contracts.

One of these was for a six-story downtown parking garage that wound up costing, what with one thing and another, just under four times the original contract figure. Each price increase was approved with virtually no discussion by key political leaders, who were invited to make speeches at the garage dedication ceremony, which fortunately was held outside the structure, which is why only two people were injured when the entire central portion of the structure collapsed during the opening prayer.

 
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  1. I’m not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O’Rourke, though, sometimes.

    BTW, on the main point, the subcontractors: This sounds a lot like the deals in which “interns” are blamed for all the screw-ups. It works because, hell, you can say you fired them, but they weren’t getting paid anyway, so who cares?

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that “landed” short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It’s interns all the way down.

    (yes, pun intended, abso-freakin-lutely)

    Read More
    • Replies: @Stan Adams

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that “landed” short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It’s interns all the way down.
     
    https://www.youtube.com/watch?v=CaOkTKfxu44
    , @Mr. Anon

    I’m not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O’Rourke, though, sometimes.
     
    Dave Barry might be the funniest guy who has ever lived. I don't think I have ever laughed harder than I have reading his books. He's not as funny as he used to be, but he had a good run (20 years or more) and he's still - even today - funnier than most people who are ostensibly humorists.
    , @Assynt
    That's like Dave cutback Davis. Spicolli says, " those guys are fags" on to his surfing title in the open
    , @TomSchmidt
    Even funnier is the angry, SJWy station director who couldn't take having been pranked. That video is even funnier than the original.
    , @Pericles
    I thought P.J. O'Rourke's Parliament of Whores was extremely funny, but it clearly belongs to a very different era. So does O'Rourke, come to think of it.
    ReplyAgree/Disagree/Etc.
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  2. Daniel H says:

    I don’t understand how even the lowest laborer on that bridge job could not have been uneasy about laying a veryyy long concrete slab supported only by two piers at either end, notwithstanding internal reinforcing. I have never even worked with concrete but, based on my basic understanding of the material – it’s poor ability to hold up to tensile forces – , that’s not what you do, again notwithstanding cable and steel internal reinforcement. The platform was supposed to be tied up to towers with steel cabling. Leave aside engineering, supervisors on the job were lacking basic construction common sense. I think that we are entering the dawn of the age of Idiocracy.

    Read More
    • Replies: @J.Ross
    I was a lowest-level laborer assembling designs wrought by degreed white collar people. Some were stunning and some made me wonder where the guy went to college. At no time was I allowed or about to express a personal opinion about something an architect signed off on, nor would anyone have paid any attention to me had I done so. One of the last things I built was a damn downright dangrous work station with a sort of overhead cubbyhole box held onto an Ikea-style particle board desk by two too-small screws. The box is positioned exactly where it needs to be for some shmo who had an unusually bad commute to rest one arm against it and talk to his coworker.
    , @songbird
    Back in 2006 a concrete ceiling panel fell in one the Boston Big Dig tunnels. By design, it was held up by exactly one bolt. It killed an illegal immigrant.
    , @Jack D
    At first I though, no, you couldn't be right - it couldn't be that stupid of a mistake, but you are right.

    The bridge was supposed to be a cable stayed bridge. There was supposed to be a big tower in the middle and diagonal cables from the top of the tower to various points on the bridge. Normally you would build the tower 1st but for some reason here they didn't.
    , @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.
    , @Anonymous
    Another relevant picture

    https://sharing.abc15.com/sharescnn/photo/2018/03/15/FIUbridgecollapseCNN_1521139921949_81129890_ver1.0_640_480.jpg
    , @JSM
    I think that we are entering the dawn of the age of Idiocracy.

    So much for Age of Aquarius.
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  3. J.Ross says: • Website

    Second paragraph “lightning store” for presumably “storm”
    feel free to delete this

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  4. J.Ross says: • Website

    Apparently these are real.

    Read More
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  5. J.Ross says: • Website
    @Daniel H
    I don't understand how even the lowest laborer on that bridge job could not have been uneasy about laying a veryyy long concrete slab supported only by two piers at either end, notwithstanding internal reinforcing. I have never even worked with concrete but, based on my basic understanding of the material - it's poor ability to hold up to tensile forces - , that's not what you do, again notwithstanding cable and steel internal reinforcement. The platform was supposed to be tied up to towers with steel cabling. Leave aside engineering, supervisors on the job were lacking basic construction common sense. I think that we are entering the dawn of the age of Idiocracy.

    I was a lowest-level laborer assembling designs wrought by degreed white collar people. Some were stunning and some made me wonder where the guy went to college. At no time was I allowed or about to express a personal opinion about something an architect signed off on, nor would anyone have paid any attention to me had I done so. One of the last things I built was a damn downright dangrous work station with a sort of overhead cubbyhole box held onto an Ikea-style particle board desk by two too-small screws. The box is positioned exactly where it needs to be for some shmo who had an unusually bad commute to rest one arm against it and talk to his coworker.

    Read More
    • Replies: @Charles Erwin Wilson II

    The box is positioned exactly where it needs to be for some shmo who had an unusually bad commute to rest one arm against it and talk to his coworker.
     
    Perhaps that was considered a feature, and not a flaw?
    , @Lot
    Sounds like a bad place to work. My experience with construction was everyone appreciates a suggestion that improves quality or safety at minimal cost.
    , @Twodees Partain
    On a DoD job in a glass plant in the early '90s, I caught an error on the electrical print which had assigned 24 circuits in a clean room directly to a 200 amp. breaker in a distribution panel. Those circuits would have been properly fed from a 200 amp. sub-panel, but the sub-panel was left out of the schematic page AND the blueprint.

    The way I found the error was seeing a wire pulling crew bundling 8, 10 and 12 gauge wire to be pulled into the distribution panel in a single conduit. It seemed that the crew that roughed in the clean room's circuits noticed that there was no sub-panel, but they somehow failed to give a shit and just listed all the branch circuit wiring to be pulled into the DP via a 2" conduit that arrived at the outside of the clean room.

    The engineers have a saying: "A mistake can be fixed with an eraser. A fuckup requires a jackhammer". That particular fuckup needed a little more finesse than a jackhammer would have provided, but the principle still holds.
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  7. vinny says:

    Looking forward to the trillion dollar infrastructure push that’ll put these projects all over the country.

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  8. @Achmed E. Newman
    I'm not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O'Rourke, though, sometimes.

    BTW, on the main point, the subcontractors: This sounds a lot like the deals in which "interns" are blamed for all the screw-ups. It works because, hell, you can say you fired them, but they weren't getting paid anyway, so who cares?

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that "landed" short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It's interns all the way down.

    (yes, pun intended, abso-freakin-lutely)
    ...

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that “landed” short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It’s interns all the way down.

    Read More
    • Replies: @Achmed E. Newman
    Thank you Stan - I was about to put this vid up this very minute! Also, though, I wanted to correct myself - it was Asiana Airlines.
    , @Luke Lea
    You don't expect us to believe it do you?
    , @SteveRogers42
    Simply the best EVER!
    , @danand
    My asian friends couldn’t contained their amusement over that broadcast. We routinely refer to it to this day with amusement. It was indeed blamed on an intern, but several people were held accountable, and lost their positions. The local anchors, Ms. Campbell’s, reputation never really recovered; she retired a year later.

    http://www.dailymail.co.uk/news/article-2377570/KTVU-staff-members-fired-Asiana-racist-gaffe-including-producer-tweeted-moments-later-oh-s-.html

    “Wi tu lo” was my favorite, but others were most taken with “Sum Ting Wong”.
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  9. anonymous • Disclaimer says:

    Was this catastrophe an example of “raggedy work”?

    As the Chicago Tribune reported May 6, 2017:

    Obama said his foundation would not hire firms [to construct his library] just because they are run by African-Americans, Latinos or women.

    “If we have to choose between somebody who is not a woman- or minority-owned vendor and who does really great work and is going to make this whole thing terrific, and somebody who’s raggedy, we will choose the folks who do the work,” Obama said to a loud roar of laughs.

    …That remark drew a joke from [Mayor] Emanuel. … when the president made his statement about raggedy businesses, the mayor said, ‘… do you really think I could say that at the City Council?’

    Read More
    • Replies: @rogue-one
    And yet, Mr. Obama during his tenure did everything to create racial spoils systems including in his favored constituency of tech firms. The school discipline wasn't about "doing the work", it was about "equity" and "diversity", as was everything else.

    Obama 2017: Competence for me, diversity for thee.
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  10. @J.Ross
    I was a lowest-level laborer assembling designs wrought by degreed white collar people. Some were stunning and some made me wonder where the guy went to college. At no time was I allowed or about to express a personal opinion about something an architect signed off on, nor would anyone have paid any attention to me had I done so. One of the last things I built was a damn downright dangrous work station with a sort of overhead cubbyhole box held onto an Ikea-style particle board desk by two too-small screws. The box is positioned exactly where it needs to be for some shmo who had an unusually bad commute to rest one arm against it and talk to his coworker.

    The box is positioned exactly where it needs to be for some shmo who had an unusually bad commute to rest one arm against it and talk to his coworker.

    Perhaps that was considered a feature, and not a flaw?

    Read More
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  11. songbird says:
    @Daniel H
    I don't understand how even the lowest laborer on that bridge job could not have been uneasy about laying a veryyy long concrete slab supported only by two piers at either end, notwithstanding internal reinforcing. I have never even worked with concrete but, based on my basic understanding of the material - it's poor ability to hold up to tensile forces - , that's not what you do, again notwithstanding cable and steel internal reinforcement. The platform was supposed to be tied up to towers with steel cabling. Leave aside engineering, supervisors on the job were lacking basic construction common sense. I think that we are entering the dawn of the age of Idiocracy.

    Back in 2006 a concrete ceiling panel fell in one the Boston Big Dig tunnels. By design, it was held up by exactly one bolt. It killed an illegal immigrant.

    Read More
    • Replies: @snorlax
    The ceiling panels (including the one that fell) were, by design, suspended in place using glue. Note for non-Bostonians: This is in an underwater tunnel.
    , @Charles Pewitt
    A giant bolt made of the finest steel screwed into a steel bracket embedded in a massively heavy cement ceiling tile in a tunnel?

    No way! Just epoxy that bastard in there and let God and gravity sort it out!

    Good enough for government work! Print up the cash and watch the construction scams crash.

    https://twitter.com/ArtHennessey/status/974462908557090816

    , @Pericles
    Mission accomplished.
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  12. @Stan Adams

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that “landed” short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It’s interns all the way down.
     
    https://www.youtube.com/watch?v=CaOkTKfxu44

    Thank you Stan – I was about to put this vid up this very minute! Also, though, I wanted to correct myself – it was Asiana Airlines.

    Read More
    • Replies: @Stan Adams
    You're welcome.

    Fake news before fake news was cool.
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  13. anon • Disclaimer says:

    “One of these was for a six-story downtown parking garage that wound up costing, what with one thing and another, just under four times the original contract figure. Each price increase was approved with virtually no discussion by key political leaders, ”

    The price increases in a standard bid contract are called “change orders,” at least here in New York, and someone (contract letting authority) has to approve them. The change order is the low low bidder’s way of racheting the contract $ back up to profitable level.

    Compliant state/municipal generally approve these, in return for campaign $. It is the Circle of Life, except with money, instead of lion cubs.

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    • Agree: Hibernian
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  14. MCM Construction Management, the company building the bridge (not responsible for the design).

    BOARD OF DIRECTORS

    From left to right: Raul Munilla, Juan Munilla, Jorge Munilla, Lou Munilla, Fernando Munilla and Pedro Munilla.

    http://www.mcm-us.com/about-us/executive-board

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    • Replies: @Lugash

    From left to right: Raul Munilla, Juan Munilla, Jorge Munilla, Lou Munilla, Fernando Munilla and Pedro Munilla.
     
    Board member Lou Munilla looks a lot like Texas ops manager Luis Munilla. Not that this clown company has any functioning controls. Concrete shouldn't be pulverized into powder falling from those distances.
    , @Rod1963
    Being a minority owned and run company means they are at the top of the list for contract awards(hence them getting a lot of government work).

    BTW here's one of their female engineers

    https://gab.ai/Ricky_Vaughn99/posts/21822758

    A real AA hire and probably socially promoted all through college.

    The design wasn't the problem it was the implementation by the clown posse and it's gang of illegal alien workers. Once the bridge was moved into place they should have kept one of the bridge movers under the mid point where the central pylon would go to minimize the load. But they didn't(either the city didn't want them or they promised the city it wasn't needed).

    Now all their f-up are coming to light and with it a ton load of lawsuits.

    The city having the deepest pockets is target #1.
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  15. Anon • Disclaimer says:

    Demographics of Haiti, pancaked concrete like Haiti. Haiti here we come!

    Read More
    • Replies: @Stan Adams
    Leftists used to moan about the fact that Cubans were automatically granted entry, while Haitians were automatically sent back. (Susan Sarandon and Tim Robbins once used the Oscars as a platform to whine about this policy.) This practice began under Bush the Father and was continued under Clinton the Horndog.

    The Cuban "exiles" in Miami never forgave Clinton for a) ending automatic entry for Cubans picked up at sea and b) sending Elián back, among other things.

    And Al Gore never forgave Alex Penelas, the Democratic mayor of Miami-Dade County, for the latter's failure to render aid and assistance during the 2000 election fiasco. (Penelas, who had been touted as one of the Democrats' rising stars and a potential Gore running mate, ditched his own party in the wake of the Elián brouhaha. In so doing, he secured his re-election as county mayor but destroyed his larger political career.) Gore later called Penelas "the single most treacherous and dishonest person" he dealt with during his presidential run.
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  16. snorlax says:
    @songbird
    Back in 2006 a concrete ceiling panel fell in one the Boston Big Dig tunnels. By design, it was held up by exactly one bolt. It killed an illegal immigrant.

    The ceiling panels (including the one that fell) were, by design, suspended in place using glue. Note for non-Bostonians: This is in an underwater tunnel.

    Read More
    • Replies: @REALBIGSE
    No, it was held up by anchor bolts held in place by epoxy mortar like millions upon millions of anchor bolts currently are in this world. The difference was that the anchor bolts were under constant direct tension, which is an unusual condition for an epoxied anchor bolt, and they found out that the epoxy doesn't respond well to constant tension and failed. They changed the codes after that. (act like you know)
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  17. @Achmed E. Newman
    Thank you Stan - I was about to put this vid up this very minute! Also, though, I wanted to correct myself - it was Asiana Airlines.

    You’re welcome.

    Fake news before fake news was cool.

    Read More
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  18. That Asiana airplane sitting by the runway half burned was something to see. It was hustled off so as too keep us faithfully using airlines. One more reason for the aisle seat; the seat bank support is furthest from the spine of the occupant of the aisle seat. The City and County of San Francisco is claiming that the young woman run over by the fire truck was already dead. Lying in the fire foam with her carry on bag. Everyone seems to have gotten off with their carry-on. Do the 4 wheelers work better than the two? And coming from Asia, at least there weren’t any …. in the overheard compartments.

    No wonder Kate Stienle’s killer got off scott free. I hope I did not misspell Kate’s name.

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  19. Luke Lea says:
    @Stan Adams

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that “landed” short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It’s interns all the way down.
     
    https://www.youtube.com/watch?v=CaOkTKfxu44

    You don’t expect us to believe it do you?

    Read More
    • Replies: @TTSSYF
    I saw it when it aired. It's absolutely true.
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  20. Mr. Blank says:

    “Penultimate” is a hilarious name. You can just see the hive of marketing people coming up with that, along with a slogan and a logo and mocked-up ads, before some unpaid intern bothers to look up the definition.

    Read More
    • Replies: @David
    There was an ad campaign in the nineties that went, "Introducing Ralph Lauren Purple Label, the penultimate collection from this master of distinctive style." It was cancelled within a day or two.
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  21. jlee says: • Website

    dave barry was “the onion” before writers for the “the onion” got their thumbs out of their mouths!

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  22. Mr. Anon says:
    @Achmed E. Newman
    I'm not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O'Rourke, though, sometimes.

    BTW, on the main point, the subcontractors: This sounds a lot like the deals in which "interns" are blamed for all the screw-ups. It works because, hell, you can say you fired them, but they weren't getting paid anyway, so who cares?

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that "landed" short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It's interns all the way down.

    (yes, pun intended, abso-freakin-lutely)
    ...

    I’m not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O’Rourke, though, sometimes.

    Dave Barry might be the funniest guy who has ever lived. I don’t think I have ever laughed harder than I have reading his books. He’s not as funny as he used to be, but he had a good run (20 years or more) and he’s still – even today – funnier than most people who are ostensibly humorists.

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    • Agree: Lot
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  23. Anonymous • Disclaimer says:

    Some of you may recall the Philadelphia building collapse a few years ago that killed several people, some of them in an “adjacent” Salvation Army store. Before this happened, I was routinely walking down the street (well it is Market St, one of the two main cross streets in Philly…). It was obvious to me a month or two in advance that something was seriously askew, and made a point of walking on the alternate side of the street (the north side, where Trader Joes’s is…) These people were just hacking away with hammers, and there seemed to be no support for the walls of the adjacent buildings. For some period of time I was walking by there every day, and every day I was wondering what in hell was going on. I got my answer…

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  24. If I scroll down to block quotes they are too narrow, but if I scroll up to them the width is right.

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  25. Lugash says:
    @ThreeCranes
    MCM Construction Management, the company building the bridge (not responsible for the design).

    BOARD OF DIRECTORS

    From left to right: Raul Munilla, Juan Munilla, Jorge Munilla, Lou Munilla, Fernando Munilla and Pedro Munilla.

    http://www.mcm-us.com/about-us/executive-board

    From left to right: Raul Munilla, Juan Munilla, Jorge Munilla, Lou Munilla, Fernando Munilla and Pedro Munilla.

    Board member Lou Munilla looks a lot like Texas ops manager Luis Munilla. Not that this clown company has any functioning controls. Concrete shouldn’t be pulverized into powder falling from those distances.

    Read More
    • Replies: @ThreeCranes
    The design was an I beam, which is not near as stable as a box section. Most bridges utilize a box somewhere in their design. In the case of a steel truss bridge, you drive right through the middle of it. In a suspension bridge, you're generally driving on a box.

    I CAD drafted (copied only) the United States Department of Transportation approved concrete bridge section plan that is used on most of the secondary roads at the county and city level in America. There's a lot of rebar in that structure, both longitudinally and transversally, vertically holding the top and bottom together. The rebar is so thick that there is no place where, if the bridge were broken open, you would see chunks of unreinforced concrete, as you see in the pictures of the fallen pedestrian bridge in Miami. All that unreinforced concrete is just dead weight.

    And as you point out--correctly--there's just no way that properly cured concrete would pulverize in the way the Miami bridge did. Just look at pictures of collapsed Cypress St. Viaduct in Oakland from the 1989 La Prieta earthquake.

    https://upload.wikimedia.org/wikipedia/commons/9/91/Cypress_collapsed.jpg

    Lotsa rebar there too.

    But as I've pointed out before, living here in Florida I see contractors pour concrete all the time and just walk away. No attempt to keep it wet for a minimum of 7 days. Concrete cures by hydration, not by drying out. Drying out stops the curing process which is a hyperbola type curve, with nearly full strength in 28 days and most of the gains achieved in 7, a practical compromise. It may well be too that the ambient temperature was too hot for a proper cure.

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  26. Jack D says:
    @Daniel H
    I don't understand how even the lowest laborer on that bridge job could not have been uneasy about laying a veryyy long concrete slab supported only by two piers at either end, notwithstanding internal reinforcing. I have never even worked with concrete but, based on my basic understanding of the material - it's poor ability to hold up to tensile forces - , that's not what you do, again notwithstanding cable and steel internal reinforcement. The platform was supposed to be tied up to towers with steel cabling. Leave aside engineering, supervisors on the job were lacking basic construction common sense. I think that we are entering the dawn of the age of Idiocracy.

    At first I though, no, you couldn’t be right – it couldn’t be that stupid of a mistake, but you are right.

    The bridge was supposed to be a cable stayed bridge. There was supposed to be a big tower in the middle and diagonal cables from the top of the tower to various points on the bridge. Normally you would build the tower 1st but for some reason here they didn’t.

    Read More
    • Replies: @Lars Porsena
    Supposedly the center tower is or was there but can only be seen in some pics. Supposedly they did not have the tension cables meant to support the bridge from it hooked up though, probably because the other half of the bridge wasn't in place yet to counterbalance it. Which would make it look like the contractors fault, they should have had temporary supports under the span until they could get the other half on and the cables tightened. We'll see when we find out more.
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  27. @Jack D
    At first I though, no, you couldn't be right - it couldn't be that stupid of a mistake, but you are right.

    The bridge was supposed to be a cable stayed bridge. There was supposed to be a big tower in the middle and diagonal cables from the top of the tower to various points on the bridge. Normally you would build the tower 1st but for some reason here they didn't.

    Supposedly the center tower is or was there but can only be seen in some pics. Supposedly they did not have the tension cables meant to support the bridge from it hooked up though, probably because the other half of the bridge wasn’t in place yet to counterbalance it. Which would make it look like the contractors fault, they should have had temporary supports under the span until they could get the other half on and the cables tightened. We’ll see when we find out more.

    Read More
    • Replies: @Mr. Anon

    Supposedly the center tower is or was there but can only be seen in some pics.
     
    Those pictures appear to be artistic renderings of what the project would have looked like when completed, probably taken from the proposal or promotional materials.

    https://www.bizjournals.com/southflorida/news/2018/03/15/fiu-s-14m-pedestrian-bridge-collapses-fatalities.html

    It looks like there was to be an additional span too; the one that collapsed was only half the final proposed bridge. I think.
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  28. Rod1963 says:
    @ThreeCranes
    MCM Construction Management, the company building the bridge (not responsible for the design).

    BOARD OF DIRECTORS

    From left to right: Raul Munilla, Juan Munilla, Jorge Munilla, Lou Munilla, Fernando Munilla and Pedro Munilla.

    http://www.mcm-us.com/about-us/executive-board

    Being a minority owned and run company means they are at the top of the list for contract awards(hence them getting a lot of government work).

    BTW here’s one of their female engineers

    https://gab.ai/Ricky_Vaughn99/posts/21822758

    A real AA hire and probably socially promoted all through college.

    The design wasn’t the problem it was the implementation by the clown posse and it’s gang of illegal alien workers. Once the bridge was moved into place they should have kept one of the bridge movers under the mid point where the central pylon would go to minimize the load. But they didn’t(either the city didn’t want them or they promised the city it wasn’t needed).

    Now all their f-up are coming to light and with it a ton load of lawsuits.

    The city having the deepest pockets is target #1.

    Read More
    • Replies: @Eustace Tilley (not)
    A culture disparaging merit
    Come Murphy's Day, learns it can't bear it.
    Equaloidist excess
    Makes societal stress.
    When they break the glass ceiling, repair it.
    , @Anonymous

    The city having the deepest pockets is target #1.
     
    Oh yeah. Everyone else declares BK, hides assets, and/or returns to their own countries.

    Downside: Taxpayers pay. Upside: We finally found a way to get them to go home.
    , @Mr. Anon
    Christ - that picture - there are a couple of people in that car, and what looks either like motor oil or blood leaking out of it; I think it's the latter.
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  29. Assynt says:
    @Achmed E. Newman
    I'm not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O'Rourke, though, sometimes.

    BTW, on the main point, the subcontractors: This sounds a lot like the deals in which "interns" are blamed for all the screw-ups. It works because, hell, you can say you fired them, but they weren't getting paid anyway, so who cares?

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that "landed" short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It's interns all the way down.

    (yes, pun intended, abso-freakin-lutely)
    ...

    That’s like Dave cutback Davis. Spicolli says, ” those guys are fags” on to his surfing title in the open

    Read More
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  30. @Anon
    Demographics of Haiti, pancaked concrete like Haiti. Haiti here we come!

    Leftists used to moan about the fact that Cubans were automatically granted entry, while Haitians were automatically sent back. (Susan Sarandon and Tim Robbins once used the Oscars as a platform to whine about this policy.) This practice began under Bush the Father and was continued under Clinton the Horndog.

    The Cuban “exiles” in Miami never forgave Clinton for a) ending automatic entry for Cubans picked up at sea and b) sending Elián back, among other things.

    And Al Gore never forgave Alex Penelas, the Democratic mayor of Miami-Dade County, for the latter’s failure to render aid and assistance during the 2000 election fiasco. (Penelas, who had been touted as one of the Democrats’ rising stars and a potential Gore running mate, ditched his own party in the wake of the Elián brouhaha. In so doing, he secured his re-election as county mayor but destroyed his larger political career.) Gore later called Penelas “the single most treacherous and dishonest person” he dealt with during his presidential run.

    Read More
    • LOL: AndrewR
    • Replies: @Hibernian
    "Gore later called Penelas 'the single most treacherous and dishonest person' he dealt with during his presidential run."

    Takes one to know one.

    It appears that Penelas was one of the few politicians who ever stood on principle in their lives.
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  31. @Stan Adams

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that “landed” short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It’s interns all the way down.
     
    https://www.youtube.com/watch?v=CaOkTKfxu44

    Simply the best EVER!

    Read More
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  32. danand says:
    @Stan Adams

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that “landed” short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It’s interns all the way down.
     
    https://www.youtube.com/watch?v=CaOkTKfxu44

    My asian friends couldn’t contained their amusement over that broadcast. We routinely refer to it to this day with amusement. It was indeed blamed on an intern, but several people were held accountable, and lost their positions. The local anchors, Ms. Campbell’s, reputation never really recovered; she retired a year later.

    http://www.dailymail.co.uk/news/article-2377570/KTVU-staff-members-fired-Asiana-racist-gaffe-including-producer-tweeted-moments-later-oh-s-.html

    “Wi tu lo” was my favorite, but others were most taken with “Sum Ting Wong”.

    Read More
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  33. REALBIGSE says:
    @Daniel H
    I don't understand how even the lowest laborer on that bridge job could not have been uneasy about laying a veryyy long concrete slab supported only by two piers at either end, notwithstanding internal reinforcing. I have never even worked with concrete but, based on my basic understanding of the material - it's poor ability to hold up to tensile forces - , that's not what you do, again notwithstanding cable and steel internal reinforcement. The platform was supposed to be tied up to towers with steel cabling. Leave aside engineering, supervisors on the job were lacking basic construction common sense. I think that we are entering the dawn of the age of Idiocracy.

    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16″ dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I’ve seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn’t support even its own weight without any stays – well, this one could (for a few days) because it wasn’t a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don’t know because I don’t have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    Read More
    • Replies: @Steve Sailer
    "The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly."

    Is that a good design?

    , @Anonymous
    u mad bro?
    , @CCZ
    I concur with your perspective. Additionally, all of the “controversy” about a female project employee is really totally irrelevant dust in the wind and distraction.

    Below are links to the documents that are available describing and documenting the design and build process. To the credit of FIU, there is a lot of documentation here!! Male licensed Professional Engineers are listed as the project engineer and bridge designer.

    The bridge was to have a “signature design” that brought attention (not the kind that the collapse is bringing) to the FIU campus and its Accelerated Bridge Design program.

    As a “design build” project, FIU and an engineering firm established the design criteria and sought proposals from qualified engineering and construction companies or partnerships.

    https://facilities.fiu.edu/projects/BT_904/FIU-Pedestrian-Bridge-Design-Criteria-2015-05-06_REV.pdf

    The complete public record of the design build process is below and includes the complete MCM proposal and preliminary plans.

    The main (collapsed) span was designed as a truss capable of supporting itself (“dead or static load”) and the pylon and cable stays were designed to give the bridge the added capacity to support the pedestrian traffic and the “harmonic vibrations” or “live load” of walking pedestrians.

    Excerpted from the MCM / Figg technical proposal design document (found as item 1 in the below link to FIU Project BT-904):

    The superstructure shape for the new signature pedestrian bridge is innovative and one-of-a-kind. We have re-invented the traditional I-beam in a magnificent scale with a special transformation of an open truss down the middle, improving both its functionality and form for a 30’ wide path.

    The concrete deck is both transversely and longitudinally post-tensioned with straight tendons. The concrete truss members and canopy will also be compressed with high strength steel cable and bars.

    The magnificent singular structural concrete shape of I-beam features this one of a kind open all elements with both structural purpose and aesthetic form. The central open truss provides bridge stiffness and also serves as unique space [for public activities].

    The stays and pylon provide the required structural design to meet the pedestrian loads for harmonic conditions of natural frequencies and create dramatic signature aesthetics that tie directly to the rhythm of the [truss] strut pattern. The tapering pylon reaches a height of approximately 109’ with 81’ above the bridge deck creating spectacular views for the users of the bridge and those driving beneath.

     

    https://facilities.fiu.edu/projects/BT-904.htm
    , @PhysicistDave
    REALBIGSE,

    It sounds as if you actually do know about this stuff.

    The news reports claimed that there was going to be a central support but that it had not yet been installed. That sounds utterly bizarre to me. A freshman physics back-of-the-envelope calculation says the stress will be four times as large if the central support is missing (twice the lever arm, twice the mass). I know it is actually more complicated (i.e., you need to worry about how the bridge flexes), but, still, this does not sound good.

    Can you give more details? Do you know if the central support was actually missing? Do you agree that it would be very strange if they put the span down without a planned central support in place?

    Again, these are honest questions: you seem to be a structural engineer or related professional, in which case I acknowledge that you are more familiar with this stuff than we physicists.

    Dave
    , @Daniel H
    >> Everybody here pretending to be a structural engineer needs to just shut the hell up.

    Just talking about Shaft.
    , @MikeW
    The way I was raised, it's very rude to tell anyone to shut up. I don't mind reading ignorant speculation, the truth eventually comes out in most cases.

    But thanks for the interesting technical explanation. I never knew there was such a thing as fake cable stays, and I'm amazed no articles I've read about this bridge mentioned that aspect of the design.

    If like many others you don't know what you're talking about, and are just trolling: well done, sir!
    , @Jack D
    I didn't know about the fake cable stays. That sounds like a big waste of money. What ever happened to form follows function?

    Was the center pier supposed to be fake too or would it have carried part of the load in the finished bridge? Even if the bridge was built to be supposedly strong enough to stand (temporarily) on its own without the pier it certainly didn't help that the tower hadn't been built yet. If nothing else, only 1 span would have failed and maybe the other span would have just tilted to the ground on one end rather than pancaking. And as Dave points out, having even 1 support cuts the stresses down tremendously because they go up exponentially with span so maybe it wouldn't have failed at all. Even if you could build the center pier later, wouldn't it have been better to build it first? I don't think that would have changed the costs at all. I've never seen a bridge where they put up the span before the piers.

    So they had the money in the budget to build a fake tower and fake cable stays but they didn't have the money to build any redundancy into the design, so that the loss of a single strut brought the whole thing down. Sounds like a metaphor for our society.
    , @The Anti-Gnostic
    There are quotes out there from the female principal of this company bragging about its supposed uniquely female aesthetic sense. So instead of designing and building to the literally pedestrian function of a footbridge they designed and built to the aesthetic of a pseudo-suspension bridge that failed under a simple stress. And nobody thought to block traffic before applying stress to this 950-ton structure.

    I'm not an architect much less a forensic engineer. Can I get paid for this?
    , @Anonymous
    REALBIGSE is 100% correct.

    The tower and cable-stays are cosmetic. This is obvious because the two spans had to support themselves without the cables, so the bridge did not need the cables to stand up.

    At first, I thought the stays were redundant rather than cosmetic, but I think REALBIGSE is correct that they are cosmetic. The "stays" are much bigger in diameter than true cables would be.

    REALBIGSE: take a look at the post with the word "shear" in it. Could that connection have been the first failure point? If not, why did the connection from the lower deck to the column shear off? How was all that load supposed to get from the PT tendons in the lower deck to the first diagonal strut?
    , @Anonymous
    Or, perhaps the failure started in the first vertical strut and caused the lower-deck-to-column connection to fail.

    Perhaps the PT tendons in the first vertical strut began to elongate, but did not fail. Then this elongation caused rotation in the column at the end, which induced torque in the deck-to-column connection causing the deck-to-column connection to fail catastrophically.

    This has some credence, I think, because I don't see any sort of special reinforcing at the base of the column to take the shear stress from the lower deck to the column/first diagonal strut, so it looks like they were relying purely on shearing strength to carry that load. That a LOT of load on that connection.
    , @Anonymous
    See the second video at this link at 0:47 to see the huge amount of PT at the lower-deck-to-column connection.

    https://www.cbsnews.com/news/florida-international-university-pedestrian-bridge-collapses-miami-florida-live-updates-2018-03-15/
    , @Anonymous
    A better picture of the PT tendons in the lower deck

    https://cbsnews2.cbsistatic.com/hub/i/r/2018/03/15/1e0f09a9-6e4b-41e7-8b4e-71993e50328d/resize/620x/59a2db4a20b38cf3ff9dc84e2be05814/180315-fiu-deleted-tweet.jpg
    , @CK
    In searching the internet, I do not find anything about Fake Cable Stay bridges. I find stuff about fan cable stay, harp cable stay and semi fan cable stay. Could I impose on you to link to information on fake cable stay bridge construction?
    , @Mr. Anon

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web.The struts transfer the shear forces (as axial forces) to the supports.
     
    Ordinarily the web of an I-beam is.........you know.............a web - a continuous band of metal or reinforced concrete, not just a few scrawny struts. Perhaps there is a reason for that. Like that it greatly increases the shear strength of the structure, and with margin.

    The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.
     
    Or in other words, it's a really crappy design.

    By the way, just because we aren't CivEs, doesn't mean we know nothing. There is a lot of expertise on this board - engineering, physics, math, etc. If you wish to not have your opinion on anything outside of your narrow field shouted down in future, you might be a little less prickly.
    , @El Dato

    The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

     

    QUALITY design shit.

    But will traumatized students march on Washington demanding better Bridge Control?

    (And, while there, can they please demand that the use of JavaScript be made illegal, because you wouldn't want to know about the crap that is being done currently to keep IT systems, uh, you know, "THE SAFETY OF YOUR DATA COMES FIRST")
    , @Hibernian
    My degree (baccalaureate) was in chemical engineering. We and the electrical engineers and some others had a watered down statics/dynamics/strength of materials course. I think others here have somewhat similar backgrounds. You remind me of the condo board president who told us owners that licensed plumbers were welcome to opine on plumbing issues in the building, implying others were not. There are multiple red flags here: fake cable staying, lack of attention to structural stability during construction, etc. Take a chill pill. Are you a structural engineer looking at this from a "there but for the grace of God go I" standpoint? You seem to be overly sympathetic to the perpetrators of this disater.
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  34. REALBIGSE says:
    @snorlax
    The ceiling panels (including the one that fell) were, by design, suspended in place using glue. Note for non-Bostonians: This is in an underwater tunnel.

    No, it was held up by anchor bolts held in place by epoxy mortar like millions upon millions of anchor bolts currently are in this world. The difference was that the anchor bolts were under constant direct tension, which is an unusual condition for an epoxied anchor bolt, and they found out that the epoxy doesn’t respond well to constant tension and failed. They changed the codes after that. (act like you know)

    Read More
    • Replies: @Mr. Anon

    No, it was held up by anchor bolts held in place by epoxy mortar like millions upon millions of anchor bolts currently are in this world. The difference was that the anchor bolts were under constant direct tension, which is an unusual condition for an epoxied anchor bolt, and they found out that the epoxy doesn’t respond well to constant tension and failed. They changed the codes after that. (act like you know)
     
    If you'r goal is to BTFO everyone here who is not a civil engineer, I guess you are succeeding. If your goal is to engender trust in civil engineers and their works - highlighting, as you are, many of their design choices that sound patently bad, even to laymen - then you might reconsider your tack.
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  35. @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    “The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.”

    Is that a good design?

    Read More
    • Replies: @Lot
    "Is that a good design?"

    No. It was such an ugly design it provoked the wrath of God. Architecture must either be humble or if grandiose should honor Him the way Notre Dame Cathedral does.

    This was an ugly post modern attempt to make a simple pedestrian bridge look like a suspension bridge marooned on land. Looked like some crap Frank Gehry would design if you made him stick to a tight budget.

    https://pbs.twimg.com/media/C_EeytwXcAA0tRH.jpg

    Pride goeth before destruction, and an haughty spirit before a fall.
    , @Momus
    He did say it was problematic.
    , @bomag

    Is that a good design?
     
    It has some simplicity of construction. The plan is to oversize it so much that failure is remote.
    , @REALBIGSE
    Many owners ban new non-redundant designs outright (they're referred to as "fracture critical" bridges, however FIU doesn't fall into this category for technical reasons), others will allow them with caveats. Depends on what your tolerance of risk is. Realize lots of older truss, suspension and tied-arch bridges are fracture critical (e.g. I-35W in Minneapolis before it went down.)
    , @bored identity
    bored identity strongly believes that the only secure path to Trump's reelection is to build mas los bridges instead of the walls:



    “It’s very important for me as a woman and an engineer to be able to promote that to my daughter, because I think women have a different perspective.

    We’re able to put in an artistic touch and we’re able to build, too.”



    Certified Bridge Artist & Builder Leonor Flores
    (MCM's Project Executive )



    (UPDATE, March 16, 2018, 11 a.m.: To clarify, Leonor Flores did not work on the FIU-Sweetwater UniversityCity Bridge project in any capacity.)

    https://i.imgur.com/jFMbhiz.jpg

    https://news.fiu.edu/2018/03/community-gathers-to-watch-950-ton-bridge-move-across-southwest-8th-street/120395

     

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  36. Anonymous • Disclaimer says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    u mad bro?

    Read More
    • LOL: TTSSYF
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  37. @Rod1963
    Being a minority owned and run company means they are at the top of the list for contract awards(hence them getting a lot of government work).

    BTW here's one of their female engineers

    https://gab.ai/Ricky_Vaughn99/posts/21822758

    A real AA hire and probably socially promoted all through college.

    The design wasn't the problem it was the implementation by the clown posse and it's gang of illegal alien workers. Once the bridge was moved into place they should have kept one of the bridge movers under the mid point where the central pylon would go to minimize the load. But they didn't(either the city didn't want them or they promised the city it wasn't needed).

    Now all their f-up are coming to light and with it a ton load of lawsuits.

    The city having the deepest pockets is target #1.

    A culture disparaging merit
    Come Murphy’s Day, learns it can’t bear it.
    Equaloidist excess
    Makes societal stress.
    When they break the glass ceiling, repair it.

    Read More
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  38. Lot says:
    @J.Ross
    I was a lowest-level laborer assembling designs wrought by degreed white collar people. Some were stunning and some made me wonder where the guy went to college. At no time was I allowed or about to express a personal opinion about something an architect signed off on, nor would anyone have paid any attention to me had I done so. One of the last things I built was a damn downright dangrous work station with a sort of overhead cubbyhole box held onto an Ikea-style particle board desk by two too-small screws. The box is positioned exactly where it needs to be for some shmo who had an unusually bad commute to rest one arm against it and talk to his coworker.

    Sounds like a bad place to work. My experience with construction was everyone appreciates a suggestion that improves quality or safety at minimal cost.

    Read More
    • Replies: @Anonymous
    Oh please. Peons don't get a hearing no matter who, when, or where.
    , @J.Ross
    You proposed designs changes on-site? Exactly how did that work? Why do I suspect you weren't using an awful lot of hand tools at the time?
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  39. Anonymous • Disclaimer says:
    @Rod1963
    Being a minority owned and run company means they are at the top of the list for contract awards(hence them getting a lot of government work).

    BTW here's one of their female engineers

    https://gab.ai/Ricky_Vaughn99/posts/21822758

    A real AA hire and probably socially promoted all through college.

    The design wasn't the problem it was the implementation by the clown posse and it's gang of illegal alien workers. Once the bridge was moved into place they should have kept one of the bridge movers under the mid point where the central pylon would go to minimize the load. But they didn't(either the city didn't want them or they promised the city it wasn't needed).

    Now all their f-up are coming to light and with it a ton load of lawsuits.

    The city having the deepest pockets is target #1.

    The city having the deepest pockets is target #1.

    Oh yeah. Everyone else declares BK, hides assets, and/or returns to their own countries.

    Downside: Taxpayers pay. Upside: We finally found a way to get them to go home.

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    • Replies: @prusmc
    We're any vibrant minority members among the injured? BRING Attorney Benjamin Crump.
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  40. Anonymous • Disclaimer says:
    @Lot
    Sounds like a bad place to work. My experience with construction was everyone appreciates a suggestion that improves quality or safety at minimal cost.

    Oh please. Peons don’t get a hearing no matter who, when, or where.

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  41. Lot says:
    @Steve Sailer
    "The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly."

    Is that a good design?

    “Is that a good design?”

    No. It was such an ugly design it provoked the wrath of God. Architecture must either be humble or if grandiose should honor Him the way Notre Dame Cathedral does.

    This was an ugly post modern attempt to make a simple pedestrian bridge look like a suspension bridge marooned on land. Looked like some crap Frank Gehry would design if you made him stick to a tight budget.

    Pride goeth before destruction, and an haughty spirit before a fall.

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    • Replies: @ThreeCranes
    "Designed as a cable-supported bridge, the project was a collaboration between MCM Construction, a prominent Miami-based contractor, and FIGG Bridge Design, based in Tallahassee. FIGG is responsible for the iconic Sunshine Skyway Bridge across Tampa Bay."

    Here's a picture of the Sunshine Skyway Bridge (in which, as someone above said, part of the load IS carried by the cables and towers).

    https://i.pinimg.com/736x/3b/97/27/3b972790329bb303156cd704fd382a11.jpg

    http://images.fineartamerica.com/images/artworkimages/mediumlarge/1/sunshine-skyway-bridge-jonathan-sabin.jpg

    As you can see, a beautiful bridge and one which the pedestrian bridge was obviously trying to echo, aesthetically anyways.

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  42. Momus says:
    @Steve Sailer
    "The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly."

    Is that a good design?

    He did say it was problematic.

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  43. Anon • Disclaimer says:
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  44. CCZ says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    I concur with your perspective. Additionally, all of the “controversy” about a female project employee is really totally irrelevant dust in the wind and distraction.

    Below are links to the documents that are available describing and documenting the design and build process. To the credit of FIU, there is a lot of documentation here!! Male licensed Professional Engineers are listed as the project engineer and bridge designer.

    The bridge was to have a “signature design” that brought attention (not the kind that the collapse is bringing) to the FIU campus and its Accelerated Bridge Design program.

    As a “design build” project, FIU and an engineering firm established the design criteria and sought proposals from qualified engineering and construction companies or partnerships.

    https://facilities.fiu.edu/projects/BT_904/FIU-Pedestrian-Bridge-Design-Criteria-2015-05-06_REV.pdf

    The complete public record of the design build process is below and includes the complete MCM proposal and preliminary plans.

    The main (collapsed) span was designed as a truss capable of supporting itself (“dead or static load”) and the pylon and cable stays were designed to give the bridge the added capacity to support the pedestrian traffic and the “harmonic vibrations” or “live load” of walking pedestrians.

    Excerpted from the MCM / Figg technical proposal design document (found as item 1 in the below link to FIU Project BT-904):

    The superstructure shape for the new signature pedestrian bridge is innovative and one-of-a-kind. We have re-invented the traditional I-beam in a magnificent scale with a special transformation of an open truss down the middle, improving both its functionality and form for a 30’ wide path.

    The concrete deck is both transversely and longitudinally post-tensioned with straight tendons. The concrete truss members and canopy will also be compressed with high strength steel cable and bars.

    The magnificent singular structural concrete shape of I-beam features this one of a kind open all elements with both structural purpose and aesthetic form. The central open truss provides bridge stiffness and also serves as unique space [for public activities].

    The stays and pylon provide the required structural design to meet the pedestrian loads for harmonic conditions of natural frequencies and create dramatic signature aesthetics that tie directly to the rhythm of the [truss] strut pattern. The tapering pylon reaches a height of approximately 109’ with 81’ above the bridge deck creating spectacular views for the users of the bridge and those driving beneath.

    https://facilities.fiu.edu/projects/BT-904.htm

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  45. @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    REALBIGSE,

    It sounds as if you actually do know about this stuff.

    The news reports claimed that there was going to be a central support but that it had not yet been installed. That sounds utterly bizarre to me. A freshman physics back-of-the-envelope calculation says the stress will be four times as large if the central support is missing (twice the lever arm, twice the mass). I know it is actually more complicated (i.e., you need to worry about how the bridge flexes), but, still, this does not sound good.

    Can you give more details? Do you know if the central support was actually missing? Do you agree that it would be very strange if they put the span down without a planned central support in place?

    Again, these are honest questions: you seem to be a structural engineer or related professional, in which case I acknowledge that you are more familiar with this stuff than we physicists.

    Dave

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    • Replies: @REALBIGSE
    Realize the MSM knows least of anyone about anything. However I believe by "central support" they meant the pylon and stays. The pylon would sit in the middle of two spans. The MSM looked at the final rendering of the bridge, got confused and didn't realize the second span hadn't been installed yet.

    If someone suggested there was going to be a pier, temporary or permanent, in the middle of undivided Tamiami Trail, they're a retard, ignore. Yes it would reduce the bending stress to 1/4 of the original (assuming two simple spans) but good luck getting a roadway engineer to sign off on that.
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  46. David says:
    @Mr. Blank
    “Penultimate” is a hilarious name. You can just see the hive of marketing people coming up with that, along with a slogan and a logo and mocked-up ads, before some unpaid intern bothers to look up the definition.

    There was an ad campaign in the nineties that went, “Introducing Ralph Lauren Purple Label, the penultimate collection from this master of distinctive style.” It was cancelled within a day or two.

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  47. Daniel H says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    >> Everybody here pretending to be a structural engineer needs to just shut the hell up.

    Just talking about Shaft.

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  48. jim jones says:

    There is a dashcam video of the bridge collapse:

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  49. “Penultimate” sounds like real-life J.H. Macklin Enterprises.

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  50. An engineer posted his analysis on the collapse, basically it seems they fucked up the tensioning of the cables that go in the concrete of the bottom of the bridge and other stuff contributed like moving supports.

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    • Replies: @RebelWriter
    Even though the guy is irritating (to me) to listen to, the second vid seems to be onto something. The bridge collapse began exactly where the lift was located, where they were working. From the drawings he has, they were required to pre-tension the rods. This very well could be what led to the collapse. If the rods failed, they were probably under-sized for installation, if not for service. I've seen things like this happen.
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  51. Every highway in America has cloverleafs that involve a simple bridge across the highway. I’ve always assumed the bridges were supported by steel beams. Surely a pedestrian walkway could’ve been built the same way at much lower cost since the load would be much less. Looks like a much too fancy design.

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  52. MikeW says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    The way I was raised, it’s very rude to tell anyone to shut up. I don’t mind reading ignorant speculation, the truth eventually comes out in most cases.

    But thanks for the interesting technical explanation. I never knew there was such a thing as fake cable stays, and I’m amazed no articles I’ve read about this bridge mentioned that aspect of the design.

    If like many others you don’t know what you’re talking about, and are just trolling: well done, sir!

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  53. drive-by says:

    I liked Dave Barry’s novels even more than his columns. I always wondered why he didn’t do more, but I also assume he knows his business better than I do. So perhaps it’s quality control, or perhaps they’re simply a lot of work and he has enough money already.

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    • Replies: @Steve Sailer
    Barry probably would have invested more work in novels if "Big Trouble" hadn't been so unlucky in its film adaptation. It was all set to open on 9/14/2001 with a terrific ensemble cast down to the smallest roles (e.g., the maid is played by a then unknown Sophia Vergara). But then 9/11 happened and a comic movie about a nuclear bomb on an airliner was inappropriate. So it got delayed going into release for six months, but the marketing budget had all been spent already in 2001, so it was rolled out in 2002 almost like "Idiocracy" and of course made no money.

    My guess is that "Big Trouble" was written to be a smaller-scale Miami version of "Bonfire of the Vanities:" a sort of "Backyard Barbecue of the Vanities." The movie is definitely better than the Bonfire movie.

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  54. Neoconned says:

    A friend of mine grew up in Miami in the 60s & told me how the Cubans turned it into paradiso fuckholio uno.

    I dunno if that’s the whole explanation but when I last visited in like 2006 the condo towers took away all the good views & the gas station we stopped at to fill up….the Arab owner had floor to ceiling bulletproof glass he hid behind….yes that was all I needed to know or see
    .
    .

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  55. I’ve been in engineering/construction for almost 40 years. I’m mechanical, not structural, but I spent 20 years as a stress analyst, and we used structural beam formulas. REALBIGSE sounds like the real deal. I can at least affirm what he wrote about anchor bolts. What he wrote about the walkway design sounds right; it was designed as a wide flange (I beam to most of you).
    I watched the video of the collapse. It was HIGHLY overstressed, that was evident. A puff of wind, or a big rig passing underneath, could have been the straw that broke the camel’s back.
    The investigation should be interesting, and will tell us what kind of country we have devolved into. The parallel incident that came to my mind was the Hyatt Regency walkway collapse in Kansas City, MO, in 1981 that killed 114 people. A very thorough investigation followed that was closely watched and reported on by the news. Because of the diversity enriched firms and contractors that I’ve read were involved with this project, I doubt the same will happen here.
    I work for a company that has regularly been among the top dozen largest engineering and construction firms in the world for the length of my career. Today it feels like we’ve forgotten what we do. We don’t generally even focus on what we do, except in the course of our work day. All the company focusses on is Diversity and Inclusion. It’s as if we sell diversity. If a woman or POC does it, it’s better because they did it, not because of any tangible evidence it’s better, but just because it wasn’t done by a white man. That’s the state of things everywhere. My company is just practicing current year corporate culture.
    Because of this, I believe we’ll see more failures like this one, and worse, too. It’s not that women and POC can’t into engineering and design, but rather because of the obsession with promoting them and their work to the point of hailing mediocrity as superior. The performance of Women and POC in engineering parallels with blacks in law schools. They’re often competent, but based purely on merit, they rarely rise above the lower levels. Merit is now based on victim status, however, and accomplishment is having a vagina or dark skin.

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  56. TTSSYF says:
    @Luke Lea
    You don't expect us to believe it do you?

    I saw it when it aired. It’s absolutely true.

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  57. Anon • Disclaimer says:

    Do like the Romans and have the designers stand under the bridge when the supports are removed, that would focus the mind.

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  58. Jack D says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    I didn’t know about the fake cable stays. That sounds like a big waste of money. What ever happened to form follows function?

    Was the center pier supposed to be fake too or would it have carried part of the load in the finished bridge? Even if the bridge was built to be supposedly strong enough to stand (temporarily) on its own without the pier it certainly didn’t help that the tower hadn’t been built yet. If nothing else, only 1 span would have failed and maybe the other span would have just tilted to the ground on one end rather than pancaking. And as Dave points out, having even 1 support cuts the stresses down tremendously because they go up exponentially with span so maybe it wouldn’t have failed at all. Even if you could build the center pier later, wouldn’t it have been better to build it first? I don’t think that would have changed the costs at all. I’ve never seen a bridge where they put up the span before the piers.

    So they had the money in the budget to build a fake tower and fake cable stays but they didn’t have the money to build any redundancy into the design, so that the loss of a single strut brought the whole thing down. Sounds like a metaphor for our society.

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  59. bomag says:
    @Steve Sailer
    "The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly."

    Is that a good design?

    Is that a good design?

    It has some simplicity of construction. The plan is to oversize it so much that failure is remote.

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  60. Anonymous • Disclaimer says:

    The bridge collapsed because the lower deck sheared off where it meets the lower end of the column shown in this photograph here

    Why? The connection between the deck and the column is carrying an enormous amount of load at that point and it does not look like there is any special connection between the two to carry that load.

    You heard it here first.

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  61. @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    There are quotes out there from the female principal of this company bragging about its supposed uniquely female aesthetic sense. So instead of designing and building to the literally pedestrian function of a footbridge they designed and built to the aesthetic of a pseudo-suspension bridge that failed under a simple stress. And nobody thought to block traffic before applying stress to this 950-ton structure.

    I’m not an architect much less a forensic engineer. Can I get paid for this?

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  62. Anonymous • Disclaimer says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    REALBIGSE is 100% correct.

    The tower and cable-stays are cosmetic. This is obvious because the two spans had to support themselves without the cables, so the bridge did not need the cables to stand up.

    At first, I thought the stays were redundant rather than cosmetic, but I think REALBIGSE is correct that they are cosmetic. The “stays” are much bigger in diameter than true cables would be.

    REALBIGSE: take a look at the post with the word “shear” in it. Could that connection have been the first failure point? If not, why did the connection from the lower deck to the column shear off? How was all that load supposed to get from the PT tendons in the lower deck to the first diagonal strut?

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  63. REALBIGSE says:
    @Steve Sailer
    "The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly."

    Is that a good design?

    Many owners ban new non-redundant designs outright (they’re referred to as “fracture critical” bridges, however FIU doesn’t fall into this category for technical reasons), others will allow them with caveats. Depends on what your tolerance of risk is. Realize lots of older truss, suspension and tied-arch bridges are fracture critical (e.g. I-35W in Minneapolis before it went down.)

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  64. @Lugash

    From left to right: Raul Munilla, Juan Munilla, Jorge Munilla, Lou Munilla, Fernando Munilla and Pedro Munilla.
     
    Board member Lou Munilla looks a lot like Texas ops manager Luis Munilla. Not that this clown company has any functioning controls. Concrete shouldn't be pulverized into powder falling from those distances.

    The design was an I beam, which is not near as stable as a box section. Most bridges utilize a box somewhere in their design. In the case of a steel truss bridge, you drive right through the middle of it. In a suspension bridge, you’re generally driving on a box.

    I CAD drafted (copied only) the United States Department of Transportation approved concrete bridge section plan that is used on most of the secondary roads at the county and city level in America. There’s a lot of rebar in that structure, both longitudinally and transversally, vertically holding the top and bottom together. The rebar is so thick that there is no place where, if the bridge were broken open, you would see chunks of unreinforced concrete, as you see in the pictures of the fallen pedestrian bridge in Miami. All that unreinforced concrete is just dead weight.

    And as you point out–correctly–there’s just no way that properly cured concrete would pulverize in the way the Miami bridge did. Just look at pictures of collapsed Cypress St. Viaduct in Oakland from the 1989 La Prieta earthquake.

    Lotsa rebar there too.

    But as I’ve pointed out before, living here in Florida I see contractors pour concrete all the time and just walk away. No attempt to keep it wet for a minimum of 7 days. Concrete cures by hydration, not by drying out. Drying out stops the curing process which is a hyperbola type curve, with nearly full strength in 28 days and most of the gains achieved in 7, a practical compromise. It may well be too that the ambient temperature was too hot for a proper cure.

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    • Replies: @Lugash
    That's makes sense about driving in/on the box when you're on a bridge, I hadn't noticed that before.

    I'm not an engineer or in construction, but I see way less rebar in that bridge than I do on construction sites before the concrete is poured. And the pieces look shorter.

    IIRC from watching a documentary years ago on skyscrapers, horizontal(?) steel I-beams provide the greatest strength to weight ratio. Not that you'd want to scale up a structural member to a giant concrete I-beam as it's own weight would create tensile forces along the bottom.

    Thanks to you(and RealBigSE) for commenting.

    From the CNN article:

    According to a fact sheet about the bridge on FIU's website, it cost $14.2 million to build and was funded as part of a $19.4 million grant from the US Department of Transportation. It was designed to withstand the strength of a Category 5 hurricane, the fact sheet said, and was supposed to last for more than 100 years.
     
    I'd assume the grant had other items, environmental studies etc. Still makes you wonder.
    , @ThreeCranes
    "the rebar is so thick"

    bad choice of words on my part. I don't mean the rebar is large in cross section. I mean it's thick like a patch of brambles are (though not randomly spaced like brambles, of course).

    , @Hibernian
    "All that unreinforced concrete is just dead weight."

    Unreninforced or lightly reinforced concrete above the neutral axis provides compressive strength where it is needed.

    I agree with your last paragraph. Contractors are very negligent about pouring concrete and ensuring that it cures properly.

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  65. Anonymous • Disclaimer says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    Or, perhaps the failure started in the first vertical strut and caused the lower-deck-to-column connection to fail.

    Perhaps the PT tendons in the first vertical strut began to elongate, but did not fail. Then this elongation caused rotation in the column at the end, which induced torque in the deck-to-column connection causing the deck-to-column connection to fail catastrophically.

    This has some credence, I think, because I don’t see any sort of special reinforcing at the base of the column to take the shear stress from the lower deck to the column/first diagonal strut, so it looks like they were relying purely on shearing strength to carry that load. That a LOT of load on that connection.

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  66. Anonymous • Disclaimer says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    See the second video at this link at 0:47 to see the huge amount of PT at the lower-deck-to-column connection.

    https://www.cbsnews.com/news/florida-international-university-pedestrian-bridge-collapses-miami-florida-live-updates-2018-03-15/

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  67. Dwright says:

    “And nobody thought to block traffic before applying stress to this 950-ton structure.”

    Hell, even Sam’s club blocks the aisle while the forklift does it’s business.

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  68. Anonymous • Disclaimer says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    A better picture of the PT tendons in the lower deck

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  69. Anonymous • Disclaimer says:
    @Daniel H
    I don't understand how even the lowest laborer on that bridge job could not have been uneasy about laying a veryyy long concrete slab supported only by two piers at either end, notwithstanding internal reinforcing. I have never even worked with concrete but, based on my basic understanding of the material - it's poor ability to hold up to tensile forces - , that's not what you do, again notwithstanding cable and steel internal reinforcement. The platform was supposed to be tied up to towers with steel cabling. Leave aside engineering, supervisors on the job were lacking basic construction common sense. I think that we are entering the dawn of the age of Idiocracy.

    Another relevant picture

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  70. REALBIGSE says:
    @PhysicistDave
    REALBIGSE,

    It sounds as if you actually do know about this stuff.

    The news reports claimed that there was going to be a central support but that it had not yet been installed. That sounds utterly bizarre to me. A freshman physics back-of-the-envelope calculation says the stress will be four times as large if the central support is missing (twice the lever arm, twice the mass). I know it is actually more complicated (i.e., you need to worry about how the bridge flexes), but, still, this does not sound good.

    Can you give more details? Do you know if the central support was actually missing? Do you agree that it would be very strange if they put the span down without a planned central support in place?

    Again, these are honest questions: you seem to be a structural engineer or related professional, in which case I acknowledge that you are more familiar with this stuff than we physicists.

    Dave

    Realize the MSM knows least of anyone about anything. However I believe by “central support” they meant the pylon and stays. The pylon would sit in the middle of two spans. The MSM looked at the final rendering of the bridge, got confused and didn’t realize the second span hadn’t been installed yet.

    If someone suggested there was going to be a pier, temporary or permanent, in the middle of undivided Tamiami Trail, they’re a retard, ignore. Yes it would reduce the bending stress to 1/4 of the original (assuming two simple spans) but good luck getting a roadway engineer to sign off on that.

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  71. JSM says:
    @Daniel H
    I don't understand how even the lowest laborer on that bridge job could not have been uneasy about laying a veryyy long concrete slab supported only by two piers at either end, notwithstanding internal reinforcing. I have never even worked with concrete but, based on my basic understanding of the material - it's poor ability to hold up to tensile forces - , that's not what you do, again notwithstanding cable and steel internal reinforcement. The platform was supposed to be tied up to towers with steel cabling. Leave aside engineering, supervisors on the job were lacking basic construction common sense. I think that we are entering the dawn of the age of Idiocracy.

    I think that we are entering the dawn of the age of Idiocracy.

    So much for Age of Aquarius.

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  72. FPD72 says:

    I’ve had some experience with Miami contractors. From 2001-2004, Florida was part of the region I managed for Construction Risk Control for a major insurance company. We had a wrap (in which insurance is provided for all of the contractors on a project) for a huge project in downtown Miami. One of my Florida staff made monthly visits to the job site. I was also responsible for hiring a full-time, on-site safety supervisor.

    Anyway, to make a long story short, I was on-site with my Florida guy when we observed a crane making picks and flying loads over Biscayne Blvd. WHILE TRAFFIC WAS PASSING UNDERNEATH, in violation of every construction related standard of care known to man. It was like pulling teeth to get on-sight management to agree to prohibit this practice going forward. The guy I hired for full time on-site safety supervision later quit in frustration over the site superintendent’s lack of concern for safety.

    We also observed several practices and design elements concerning the building envelope that we thought would come back to bite us for construction defect claims due to water penetration. We were not wrong.

    Read A Man in Full by Tom Wolfe and substitute “Cuban” for “Black” in The Atlanta Way and you get a pretty good idea about The Miami Way when it comes to public sector design and construction.

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  73. @Achmed E. Newman
    I'm not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O'Rourke, though, sometimes.

    BTW, on the main point, the subcontractors: This sounds a lot like the deals in which "interns" are blamed for all the screw-ups. It works because, hell, you can say you fired them, but they weren't getting paid anyway, so who cares?

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that "landed" short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It's interns all the way down.

    (yes, pun intended, abso-freakin-lutely)
    ...

    Even funnier is the angry, SJWy station director who couldn’t take having been pranked. That video is even funnier than the original.

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  74. @songbird
    Back in 2006 a concrete ceiling panel fell in one the Boston Big Dig tunnels. By design, it was held up by exactly one bolt. It killed an illegal immigrant.

    A giant bolt made of the finest steel screwed into a steel bracket embedded in a massively heavy cement ceiling tile in a tunnel?

    No way! Just epoxy that bastard in there and let God and gravity sort it out!

    Good enough for government work! Print up the cash and watch the construction scams crash.

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    • Replies: @J.Ross
    A good theme to follow if you haven't noticed it already: leftists depend on denying the reality of evil. The idea that a person would indulge in ultimately murderous venality is not a danger to be guarded against with morality and ethics, it's not a historically evidenced event to look into, it's "too horrible to contemplate." All the other brilliant leftoid proposals for society make sense if you simply forget how horrible humans can be.
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  75. CK says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    In searching the internet, I do not find anything about Fake Cable Stay bridges. I find stuff about fan cable stay, harp cable stay and semi fan cable stay. Could I impose on you to link to information on fake cable stay bridge construction?

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  76. Mr. Anon says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web.The struts transfer the shear forces (as axial forces) to the supports.

    Ordinarily the web of an I-beam is………you know………….a web – a continuous band of metal or reinforced concrete, not just a few scrawny struts. Perhaps there is a reason for that. Like that it greatly increases the shear strength of the structure, and with margin.

    The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    Or in other words, it’s a really crappy design.

    By the way, just because we aren’t CivEs, doesn’t mean we know nothing. There is a lot of expertise on this board – engineering, physics, math, etc. If you wish to not have your opinion on anything outside of your narrow field shouted down in future, you might be a little less prickly.

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  77. El Dato says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    QUALITY design shit.

    But will traumatized students march on Washington demanding better Bridge Control?

    (And, while there, can they please demand that the use of JavaScript be made illegal, because you wouldn’t want to know about the crap that is being done currently to keep IT systems, uh, you know, “THE SAFETY OF YOUR DATA COMES FIRST”)

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  78. Mr. Anon says:
    @REALBIGSE
    No, it was held up by anchor bolts held in place by epoxy mortar like millions upon millions of anchor bolts currently are in this world. The difference was that the anchor bolts were under constant direct tension, which is an unusual condition for an epoxied anchor bolt, and they found out that the epoxy doesn't respond well to constant tension and failed. They changed the codes after that. (act like you know)

    No, it was held up by anchor bolts held in place by epoxy mortar like millions upon millions of anchor bolts currently are in this world. The difference was that the anchor bolts were under constant direct tension, which is an unusual condition for an epoxied anchor bolt, and they found out that the epoxy doesn’t respond well to constant tension and failed. They changed the codes after that. (act like you know)

    If you’r goal is to BTFO everyone here who is not a civil engineer, I guess you are succeeding. If your goal is to engender trust in civil engineers and their works – highlighting, as you are, many of their design choices that sound patently bad, even to laymen – then you might reconsider your tack.

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  79. Mr. Anon says:
    @Rod1963
    Being a minority owned and run company means they are at the top of the list for contract awards(hence them getting a lot of government work).

    BTW here's one of their female engineers

    https://gab.ai/Ricky_Vaughn99/posts/21822758

    A real AA hire and probably socially promoted all through college.

    The design wasn't the problem it was the implementation by the clown posse and it's gang of illegal alien workers. Once the bridge was moved into place they should have kept one of the bridge movers under the mid point where the central pylon would go to minimize the load. But they didn't(either the city didn't want them or they promised the city it wasn't needed).

    Now all their f-up are coming to light and with it a ton load of lawsuits.

    The city having the deepest pockets is target #1.

    Christ – that picture – there are a couple of people in that car, and what looks either like motor oil or blood leaking out of it; I think it’s the latter.

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  80. Mr. Anon says:
    @Lars Porsena
    Supposedly the center tower is or was there but can only be seen in some pics. Supposedly they did not have the tension cables meant to support the bridge from it hooked up though, probably because the other half of the bridge wasn't in place yet to counterbalance it. Which would make it look like the contractors fault, they should have had temporary supports under the span until they could get the other half on and the cables tightened. We'll see when we find out more.

    Supposedly the center tower is or was there but can only be seen in some pics.

    Those pictures appear to be artistic renderings of what the project would have looked like when completed, probably taken from the proposal or promotional materials.

    https://www.bizjournals.com/southflorida/news/2018/03/15/fiu-s-14m-pedestrian-bridge-collapses-fatalities.html

    It looks like there was to be an additional span too; the one that collapsed was only half the final proposed bridge. I think.

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  81. How difficult is it to build a pedestrian bridge over a highway that does not fall down? Even third world countries can get the job done.

    Here is one in Santo Domingo at Km. 9 of Route 1. The local authorities were threatening to evict Haitian street vendors from the bridge.

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    • Replies: @RebelWriter
    The most obvious difference is that this one is steel. From the photo I also know that there is a foundation support in the middle of the span. Otherwise the design is similar.

    I have never before seen a truss made of pre-fab concrete, as the one is Florida was. I wouldn't be at all surprised if they don't find some fault with the fabricator (though I believe from what I've seen that the fault lay with the design). The concrete didn't have the look of properly cured concrete. I once worked on a project we called "the parking garage," because the structure was pre-fabbed concrete, and did resemble a parking garage made of the same. It was a polymer plant, however, with some very large, and very hot equipment. Hot steel expands and generates forces which must be controlled, and are therefore transferred to the structure. It's still standing and working fine, as are God knows how many actual parking garages. I've never seen one fail and crumble the way this one did.

    The Florida walkway is/was more of a truss than a suspension bridge.
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  82. Mr. Anon says:

    One should bear in mind that this kind of thing is not unprecedented:

    https://en.wikipedia.org/wiki/Hyatt_Regency_walkway_collapse

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  83. Hibernian says:
    @Stan Adams
    Leftists used to moan about the fact that Cubans were automatically granted entry, while Haitians were automatically sent back. (Susan Sarandon and Tim Robbins once used the Oscars as a platform to whine about this policy.) This practice began under Bush the Father and was continued under Clinton the Horndog.

    The Cuban "exiles" in Miami never forgave Clinton for a) ending automatic entry for Cubans picked up at sea and b) sending Elián back, among other things.

    And Al Gore never forgave Alex Penelas, the Democratic mayor of Miami-Dade County, for the latter's failure to render aid and assistance during the 2000 election fiasco. (Penelas, who had been touted as one of the Democrats' rising stars and a potential Gore running mate, ditched his own party in the wake of the Elián brouhaha. In so doing, he secured his re-election as county mayor but destroyed his larger political career.) Gore later called Penelas "the single most treacherous and dishonest person" he dealt with during his presidential run.

    “Gore later called Penelas ‘the single most treacherous and dishonest person’ he dealt with during his presidential run.”

    Takes one to know one.

    It appears that Penelas was one of the few politicians who ever stood on principle in their lives.

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    • Replies: @Stan Adams
    http://www.miaminewtimes.com/news/the-dead-end-kid-6354322

    A few years ago, the notion of Penelas distancing himself from Gore and the Democrats was unthinkable. Through the first seven years of the Clinton-Gore administration, Penelas never missed an opportunity to be seen with the president and vice president. When Gore began his campaign for the presidency, Penelas hung so tightly to the vice president's coattails he could have been arrested for stalking.

    In 1998, at the height of the impeachment scandal surrounding Clinton, Penelas unexpectedly met with Gore in Washington, leading some to speculate that Gore was preparing to tap Penelas for a cabinet post in the event Clinton was forced to resign. The mayor relished such rumors. "I've heard it on Spanish radio, from people in the street," he told the Miami Herald at the time. "I'm very flattered by it."

    A year later he was no less flattered when Newsweek claimed he was included on a list of possible running mates being considered by the Gore campaign, a rumor Penelas's own minions had been eagerly spreading for weeks before the magazine's article appeared. In response to the story, Penelas proudly declared he was ready to serve "in any capacity." At the very least it seemed certain that if Gore were elected president, Penelas would be in line for a cabinet position. Conjecture leaned toward a post as secretary of housing and urban development.

    [...]

    Penelas's political future began unraveling with the arrival of little Elian Gonzalez. Even before the April 22 raid on the home of the boy's Miami relatives, Penelas believed the administration's handling of the Elian affair had hindered him. The mayor's now-infamous statement in front of the federal courthouse was a measure of his personal frustration with a Washington bureaucracy that didn't seem appropriately sensitive to his local political needs.

    After Penelas personally attacked Clinton and threatened to hold the president and Attorney General Janet Reno responsible for any violent civil unrest in Miami, the president responded in kind: He froze out the mayor. According to one source close to Penelas, in the weeks following that defiant statement, Clinton refused to meet or talk with Penelas, despite repeated requests by the mayor.

    Politically speaking, the president essentially sent Penelas to bed without supper. He didn't publicly humiliate the mayor or retaliate by trying to hold up federal funds intended for Miami-Dade. He simply spanked him.

    [...]

    In the weeks following the raid that removed Elian, Penelas's own mayoral re-election campaign began moving into high gear. Perhaps not surprisingly he figured it was best for him to steer clear of Gore, and so he refused to attend any functions with the vice president. Although members of the Gore campaign had hoped Penelas would have shown more loyalty to the vice president, they understood he was in a tough election battle of his own.

    But there was an expectation among Democrats that after Penelas won his election, he would be free to help the vice president.

    [...]

    Martinez recalls that he and Penelas were supposed to host a joint press conference in support of Gore on October 18. Both the date and the time had been selected to accommodate Penelas's schedule. Yet Penelas failed to show. Later that day he boarded a plane for his vacation in Spain. "When the going gets tough, he just hides," Martinez says derisively. "Alex is weak; he doesn't have a backbone. He is just a wimp. He only cares for Alex Penelas and doesn't care for anyone else."

    Penelas campaign advisor Ric Katz claims the mayor never committed to attending that press conference. Martinez disagrees. Lobbyist Korge floats this comical excuse: Penelas was unable to attend the October 18 event because he had to get home and pack for his vacation. Katz, however, did promise that when Penelas returned from Spain at the end of October he would actively barnstorm for the vice president and be "visible" in the crucial closing days. Despite that promise Penelas remained virtually invisible. Even during last week's star-studded midnight rally on the sands of Miami Beach -- the very last day of the campaign -- Penelas was a no-show. "It was just very late at night," sputters Penelas spokesman Juan Mendieta.

    According to pollster Schroth, Gore ended up receiving only 22 percent of the Cuban-American vote, about half of what Clinton garnered in 1996.
     

    Incidentally, Jim DeFede, the author of this piece, was fired from the Miami Herald in 2005 for illegally recording a phone conversation with the disgraced Arthur Teele, at one time the most powerful black in Miami. Teele was calling from a payphone in the Herald lobby.

    (This conversation took place the day before the Miami New Times - the "alternative" weekly where DeFede got his start - was set to publish a lengthy piece about Teele's corruption, drug use, and fondness for callboys.)

    After hanging up the phone, Teele took a gun out of his pocket and blew his brains out. The next morning, Herald readers were treated to a huge front-page picture of his blood-soaked corpse.

    DeFede, who weighs at least 400 pounds, now works for a local television station. Here he is seen looking positively svelte while interviewing Marco the Rube:
    https://www.youtube.com/watch?v=C-rQ1Adk5lo

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  84. prusmc says: • Website
    @Anonymous

    The city having the deepest pockets is target #1.
     
    Oh yeah. Everyone else declares BK, hides assets, and/or returns to their own countries.

    Downside: Taxpayers pay. Upside: We finally found a way to get them to go home.

    We’re any vibrant minority members among the injured? BRING Attorney Benjamin Crump.

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  85. @Jonathan Mason
    How difficult is it to build a pedestrian bridge over a highway that does not fall down? Even third world countries can get the job done.

    Here is one in Santo Domingo at Km. 9 of Route 1. The local authorities were threatening to evict Haitian street vendors from the bridge.


    https://i0.wp.com/www.idominicanas.com/wp-content/uploads/2016/07/PuentepeatonalKM9AutopistaDuarte.jpg?w=640

    The most obvious difference is that this one is steel. From the photo I also know that there is a foundation support in the middle of the span. Otherwise the design is similar.

    I have never before seen a truss made of pre-fab concrete, as the one is Florida was. I wouldn’t be at all surprised if they don’t find some fault with the fabricator (though I believe from what I’ve seen that the fault lay with the design). The concrete didn’t have the look of properly cured concrete. I once worked on a project we called “the parking garage,” because the structure was pre-fabbed concrete, and did resemble a parking garage made of the same. It was a polymer plant, however, with some very large, and very hot equipment. Hot steel expands and generates forces which must be controlled, and are therefore transferred to the structure. It’s still standing and working fine, as are God knows how many actual parking garages. I’ve never seen one fail and crumble the way this one did.

    The Florida walkway is/was more of a truss than a suspension bridge.

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  86. Hibernian says:
    @REALBIGSE
    Everybody here pretending to be a structural engineer needs to just shut the hell up. You sound like liberals talking about guns, you know NOTHING.

    The bridge was a fake cable stay. The stays they would have put on later would have been empty 16" dia. steel pipes that did nothing structurally. A lot of pedestrian bridges are make to look like fake cable stay, arch or suspension bridges, but this is by far the most elaborate I've seen. It explains the big question of why they used span-by-span construction. Normally a cable-stay bridge couldn't support even its own weight without any stays - well, this one could (for a few days) because it wasn't a cable stay bridge and designed as a simple beam.

    The bridge was one giant I beam with the canopy as the top flange, the walking surface as the bottom flange, and the struts as the web. The struts transfer the shear forces (as axial forces) to the supports. The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly.

    The struts in axial tension were reinforced with PT bars (PT = post-tensioning, i.e. using bars or cables to apply a compressive force to concrete after its been cast) (yes genius, we have ways to deal with tension in concrete). Apparently, some of the PT bars in the second strut from the pylon pier had detensioned and this caused cracking, so they sent some workers to restress them. It shortly collapsed with the failure starting right at the top of the strut they were tensioning.

    So, the failure happened because a strut failed. What caused it to fail? I don't know because I don't have any good information and neither do you so kindly stop speculating especially about technical things you know jack about.

    My degree (baccalaureate) was in chemical engineering. We and the electrical engineers and some others had a watered down statics/dynamics/strength of materials course. I think others here have somewhat similar backgrounds. You remind me of the condo board president who told us owners that licensed plumbers were welcome to opine on plumbing issues in the building, implying others were not. There are multiple red flags here: fake cable staying, lack of attention to structural stability during construction, etc. Take a chill pill. Are you a structural engineer looking at this from a “there but for the grace of God go I” standpoint? You seem to be overly sympathetic to the perpetrators of this disater.

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  87. Jack D says:

    Any early 19th century American bridge builder (not even someone with an engineering degree – just a skilled craftsman) could have done a wooden truss bridge at 1/100th the cost with enough redundancy so that the loss of a single strut would not have caused the entire structure to fail (at a minimum it would have had two sets of struts, one on either side of the deck). He probably would have done criss-crossing scissor trusses so it would have even more redundancy.

    If they told him they wanted to shade the pedestrians from the sun and rain, he would have done it as a covered bridge. But only a modern lady genius could build a bridge with a single set of struts and fake cable stays so that the loss of a single strut would send the whole thing crashing to the ground. What a genius idea to put the struts right in the middle of the deck instead of at the sides. A real aid to the blind. But it looked fashionable.

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  88. @J.Ross
    I was a lowest-level laborer assembling designs wrought by degreed white collar people. Some were stunning and some made me wonder where the guy went to college. At no time was I allowed or about to express a personal opinion about something an architect signed off on, nor would anyone have paid any attention to me had I done so. One of the last things I built was a damn downright dangrous work station with a sort of overhead cubbyhole box held onto an Ikea-style particle board desk by two too-small screws. The box is positioned exactly where it needs to be for some shmo who had an unusually bad commute to rest one arm against it and talk to his coworker.

    On a DoD job in a glass plant in the early ’90s, I caught an error on the electrical print which had assigned 24 circuits in a clean room directly to a 200 amp. breaker in a distribution panel. Those circuits would have been properly fed from a 200 amp. sub-panel, but the sub-panel was left out of the schematic page AND the blueprint.

    The way I found the error was seeing a wire pulling crew bundling 8, 10 and 12 gauge wire to be pulled into the distribution panel in a single conduit. It seemed that the crew that roughed in the clean room’s circuits noticed that there was no sub-panel, but they somehow failed to give a shit and just listed all the branch circuit wiring to be pulled into the DP via a 2″ conduit that arrived at the outside of the clean room.

    The engineers have a saying: “A mistake can be fixed with an eraser. A fuckup requires a jackhammer”. That particular fuckup needed a little more finesse than a jackhammer would have provided, but the principle still holds.

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    • Replies: @J.Ross
    Those are electricians, though. I want to believe that an electrician or a plumber would get attention. You ignore an electrician, you'll get attention from the fire department.
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  89. @Steve Sailer
    "The problem with this design is that its not very redundant, in particular if one of the struts fails then the whole bridge will go down instantly."

    Is that a good design?

    bored identity strongly believes that the only secure path to Trump’s reelection is to build mas los bridges instead of the walls:

    “It’s very important for me as a woman and an engineer to be able to promote that to my daughter, because I think women have a different perspective.

    We’re able to put in an artistic touch and we’re able to build, too.”

    Certified Bridge Artist & Builder Leonor Flores
    (MCM’s Project Executive )

    (UPDATE, March 16, 2018, 11 a.m.: To clarify, Leonor Flores did not work on the FIU-Sweetwater UniversityCity Bridge project in any capacity.)

    https://news.fiu.edu/2018/03/community-gathers-to-watch-950-ton-bridge-move-across-southwest-8th-street/120395

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  90. @drive-by
    I liked Dave Barry's novels even more than his columns. I always wondered why he didn't do more, but I also assume he knows his business better than I do. So perhaps it's quality control, or perhaps they're simply a lot of work and he has enough money already.

    Barry probably would have invested more work in novels if “Big Trouble” hadn’t been so unlucky in its film adaptation. It was all set to open on 9/14/2001 with a terrific ensemble cast down to the smallest roles (e.g., the maid is played by a then unknown Sophia Vergara). But then 9/11 happened and a comic movie about a nuclear bomb on an airliner was inappropriate. So it got delayed going into release for six months, but the marketing budget had all been spent already in 2001, so it was rolled out in 2002 almost like “Idiocracy” and of course made no money.

    My guess is that “Big Trouble” was written to be a smaller-scale Miami version of “Bonfire of the Vanities:” a sort of “Backyard Barbecue of the Vanities.” The movie is definitely better than the Bonfire movie.

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  91. Lugash says:
    @ThreeCranes
    The design was an I beam, which is not near as stable as a box section. Most bridges utilize a box somewhere in their design. In the case of a steel truss bridge, you drive right through the middle of it. In a suspension bridge, you're generally driving on a box.

    I CAD drafted (copied only) the United States Department of Transportation approved concrete bridge section plan that is used on most of the secondary roads at the county and city level in America. There's a lot of rebar in that structure, both longitudinally and transversally, vertically holding the top and bottom together. The rebar is so thick that there is no place where, if the bridge were broken open, you would see chunks of unreinforced concrete, as you see in the pictures of the fallen pedestrian bridge in Miami. All that unreinforced concrete is just dead weight.

    And as you point out--correctly--there's just no way that properly cured concrete would pulverize in the way the Miami bridge did. Just look at pictures of collapsed Cypress St. Viaduct in Oakland from the 1989 La Prieta earthquake.

    https://upload.wikimedia.org/wikipedia/commons/9/91/Cypress_collapsed.jpg

    Lotsa rebar there too.

    But as I've pointed out before, living here in Florida I see contractors pour concrete all the time and just walk away. No attempt to keep it wet for a minimum of 7 days. Concrete cures by hydration, not by drying out. Drying out stops the curing process which is a hyperbola type curve, with nearly full strength in 28 days and most of the gains achieved in 7, a practical compromise. It may well be too that the ambient temperature was too hot for a proper cure.

    That’s makes sense about driving in/on the box when you’re on a bridge, I hadn’t noticed that before.

    I’m not an engineer or in construction, but I see way less rebar in that bridge than I do on construction sites before the concrete is poured. And the pieces look shorter.

    IIRC from watching a documentary years ago on skyscrapers, horizontal(?) steel I-beams provide the greatest strength to weight ratio. Not that you’d want to scale up a structural member to a giant concrete I-beam as it’s own weight would create tensile forces along the bottom.

    Thanks to you(and RealBigSE) for commenting.

    From the CNN article:

    According to a fact sheet about the bridge on FIU’s website, it cost $14.2 million to build and was funded as part of a $19.4 million grant from the US Department of Transportation. It was designed to withstand the strength of a Category 5 hurricane, the fact sheet said, and was supposed to last for more than 100 years.

    I’d assume the grant had other items, environmental studies etc. Still makes you wonder.

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    • Replies: @ThreeCranes
    It's not an exaggeration to say that most structures built by human hands are boxes.

    A unibody automobile is a box. A ship is a long shoebox and the stresses in the hull are analyzed as such. Of course, your house, furniture (including the four-legged chair at your dining room table) are boxes. A chimney or skyscraper is just an upright box. A cylinder, like an airplane fuselage, can be thought of as a circular box. The walls of your house are thin-section boxes.

    If you want to improve your home project instantly, put a lid on it. Close it up. Add an access hatch. Many problems with amateur construction come from not boxing something in. I see this mistake all the time. Here's an example: a 2x4 framed wall with 3/4" ply sheathing on one face is much weaker than the same faced on both sides with 3/8" ply, even though they weigh the same. Grab one side of a rigid suitcase that is lying open and you can easily twist it with your hands, closed it's got integrity.

    Many amateurs believe that by substituting weight for integral form that they can make something stronger. This has to be carefully engineered. Anything cantilevered--that is, projecting out into space from one end--must be very carefully designed. A convertible automobile must have special bracing because the roof, the top of the box, is not there to provide integral rigidity. Coupes require thickened pillars front and rear, to resist racking. And so on.
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  92. CCZ says:

    Not sure why this primary source information is being ignored, so I have slightly revised and will post again and see what happens.

    Below are links to the documents that are available describing and documenting the design and build process. To the credit of FIU, there is a lot of documentation here!! [Male] Licensed Professional Engineers are listed as the project engineer and bridge designer.

    The bridge was to have a “signature design” that brought attention (not the kind that the collapse is bringing) to the FIU campus and its Accelerated Bridge Design program.

    As a “design build” project, FIU and an engineering firm established the design criteria and sought proposals from qualified engineering and construction companies or partnerships.

    https://facilities.fiu.edu/projects/BT_904/FIU-Pedestrian-Bridge-Design-Criteria-2015-05-06_REV.pdf

    The complete public record of the design build process is below and includes the complete MCM proposal and preliminary plans.

    The main (collapsed) span was designed as an I beam with a truss web capable of supporting itself and the pylon and stays were designed to give the bridge the structural capacity to “meet the pedestrian loads for harmonic conditions of natural frequencies” arising from walking pedestrians.

    Excerpted from the MCM / Figg technical proposal design document (found as item 1 in the below link to FIU Project BT-904):

    The superstructure shape for the new signature pedestrian bridge is innovative and one-of-a-kind. We have re-invented the traditional I-beam in a magnificent scale with a special transformation of an open truss down the middle, improving both its functionality and form for a 30’ wide path.

    The concrete deck is both transversely and longitudinally post-tensioned with straight tendons. The concrete truss members and canopy will also be compressed with high strength steel cable and bars.

    The magnificent singular structural concrete shape of I-beam features this one of a kind open all elements with both structural purpose and aesthetic form. The central open truss provides bridge stiffness and also serves as unique space [for public activities].

    The stays and pylon provide the required structural design to meet the pedestrian loads for harmonic conditions of natural frequencies and create dramatic signature aesthetics that tie directly to the rhythm of the [truss] strut pattern. The tapering pylon reaches a height of approximately 109’ with 81’ above the bridge deck creating spectacular views for the users of the bridge and those driving beneath.

    https://facilities.fiu.edu/projects/BT-904.htm

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  93. Pericles says:
    @Achmed E. Newman
    I'm not sure of his political views as of late, but Dave Barry has always been an extremely funny guy. I get him confused a lot with P.J. O'Rourke, though, sometimes.

    BTW, on the main point, the subcontractors: This sounds a lot like the deals in which "interns" are blamed for all the screw-ups. It works because, hell, you can say you fired them, but they weren't getting paid anyway, so who cares?

    Do you remember the hilarious San Francisco newscast on the Oceana 777 that "landed" short at SFO with the fake fun Oriental names? That screw-up was blamed on an intern at the TV station. The intern, in-turn, stated that he had gotten wrong information from an intern at the FAA or NTSB. It's interns all the way down.

    (yes, pun intended, abso-freakin-lutely)
    ...

    I thought P.J. O’Rourke’s Parliament of Whores was extremely funny, but it clearly belongs to a very different era. So does O’Rourke, come to think of it.

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    • Replies: @Achmed E. Newman
    Believe it or not, back when I read his stuff, I thought that title, Parliament of Whores, was a bit harsh. Now, I think it wouldn't be going far enough as a good description of the US Congress.
    , @Jim Don Bob

    So does O’Rourke, come to think of it.
     
    He said he voted for HRC, so f**k him.
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  94. Fourteen point two million was a unbelievable amount of money to pay for a pedestrian bridge for students to walk across eight lanes of traffic from the City of “Sweetwater” to the F.I.U. campus.

    “School Crossing Guards” get paid seventeen dollars an hour for part-time work in our neck of the woods.

    If college age students do not have the motor or cognition skills to cross on a red light without outside help, then I submit it would have been a Hell of a lot cheaper and less destructive to hire “Crossing Guards” rather than the elevated collapsed boondoggle that cost lives and will result in a decade of lawsuits owned by the taxpayers.

    Fourteen point two million could have covered a lot of “Crossing Guard” payroll.

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  95. Pericles says:
    @songbird
    Back in 2006 a concrete ceiling panel fell in one the Boston Big Dig tunnels. By design, it was held up by exactly one bolt. It killed an illegal immigrant.

    Mission accomplished.

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  96. @ThreeCranes
    The design was an I beam, which is not near as stable as a box section. Most bridges utilize a box somewhere in their design. In the case of a steel truss bridge, you drive right through the middle of it. In a suspension bridge, you're generally driving on a box.

    I CAD drafted (copied only) the United States Department of Transportation approved concrete bridge section plan that is used on most of the secondary roads at the county and city level in America. There's a lot of rebar in that structure, both longitudinally and transversally, vertically holding the top and bottom together. The rebar is so thick that there is no place where, if the bridge were broken open, you would see chunks of unreinforced concrete, as you see in the pictures of the fallen pedestrian bridge in Miami. All that unreinforced concrete is just dead weight.

    And as you point out--correctly--there's just no way that properly cured concrete would pulverize in the way the Miami bridge did. Just look at pictures of collapsed Cypress St. Viaduct in Oakland from the 1989 La Prieta earthquake.

    https://upload.wikimedia.org/wikipedia/commons/9/91/Cypress_collapsed.jpg

    Lotsa rebar there too.

    But as I've pointed out before, living here in Florida I see contractors pour concrete all the time and just walk away. No attempt to keep it wet for a minimum of 7 days. Concrete cures by hydration, not by drying out. Drying out stops the curing process which is a hyperbola type curve, with nearly full strength in 28 days and most of the gains achieved in 7, a practical compromise. It may well be too that the ambient temperature was too hot for a proper cure.

    “the rebar is so thick”

    bad choice of words on my part. I don’t mean the rebar is large in cross section. I mean it’s thick like a patch of brambles are (though not randomly spaced like brambles, of course).

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  97. @Lugash
    That's makes sense about driving in/on the box when you're on a bridge, I hadn't noticed that before.

    I'm not an engineer or in construction, but I see way less rebar in that bridge than I do on construction sites before the concrete is poured. And the pieces look shorter.

    IIRC from watching a documentary years ago on skyscrapers, horizontal(?) steel I-beams provide the greatest strength to weight ratio. Not that you'd want to scale up a structural member to a giant concrete I-beam as it's own weight would create tensile forces along the bottom.

    Thanks to you(and RealBigSE) for commenting.

    From the CNN article:

    According to a fact sheet about the bridge on FIU's website, it cost $14.2 million to build and was funded as part of a $19.4 million grant from the US Department of Transportation. It was designed to withstand the strength of a Category 5 hurricane, the fact sheet said, and was supposed to last for more than 100 years.
     
    I'd assume the grant had other items, environmental studies etc. Still makes you wonder.

    It’s not an exaggeration to say that most structures built by human hands are boxes.

    A unibody automobile is a box. A ship is a long shoebox and the stresses in the hull are analyzed as such. Of course, your house, furniture (including the four-legged chair at your dining room table) are boxes. A chimney or skyscraper is just an upright box. A cylinder, like an airplane fuselage, can be thought of as a circular box. The walls of your house are thin-section boxes.

    If you want to improve your home project instantly, put a lid on it. Close it up. Add an access hatch. Many problems with amateur construction come from not boxing something in. I see this mistake all the time. Here’s an example: a 2×4 framed wall with 3/4″ ply sheathing on one face is much weaker than the same faced on both sides with 3/8″ ply, even though they weigh the same. Grab one side of a rigid suitcase that is lying open and you can easily twist it with your hands, closed it’s got integrity.

    Many amateurs believe that by substituting weight for integral form that they can make something stronger. This has to be carefully engineered. Anything cantilevered–that is, projecting out into space from one end–must be very carefully designed. A convertible automobile must have special bracing because the roof, the top of the box, is not there to provide integral rigidity. Coupes require thickened pillars front and rear, to resist racking. And so on.

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    • Replies: @RebelWriter
    Everything is a series of beams, in theory. All stress analysis (except finite element analysis) is based on structural beam formulas. A box is simply a way of distributing forces.

    The basic formula for stress is P=S/A, where P is resultant stress, S is force, and A is area. A small force on a small area results in an acceptable stress. A small force on a large area results in little stress. A large stress on a small area results in a high stress. "Area" is cross-sectional area, typically steel. The properties of the steel (or concrete, or wood, etc.) are part of the long equation. So your statement about using "weight", by which you mean "more steel" or whatever, is absolutely wrong, because "weight" is a key factor in stress, and you most certainly can reduce stress by adding more of it.

    This is true, I'm sure, for ships and cars, as they are basically steel structures. It's most definitely the case for actual structures, like buildings and bridges (and pipe lines).

    Now, what you can say is that by properly distributing those forces you can use smaller components, which is true. The building frames we design today are much, much lighter than those we designed 30 years ago.

    A cantilevered beam in practical use is a rare thing. This is simply because all the forces are multiplied by the length of the cantilever; the "fat man standing on it" analogy. A 200 lb. man standing on the end of a 10 ft. cantilever creates 2000 ft. lbs of moment (bending stress) on the beam support at the other end. A 300 lb. man will put 3000 ft. lbs of stress on the support. And we're not even accounting for the shear stresses. 2000 lbs. on a W12 x 32 isn't much, but on a 3 x 3 x 1/4 angle, it's probably going to fail. That's why there is framing, cross-bracing, etc., in order to distribute loads. Of course, this is cartoon level engineering, and the structural/civil guys will probably pick at me about this.

    The place one most often sees cantilevers are building fronts, weather protection over entrances, and those are designed by architects, and no self-respecting structural engineer would do that, but architects are all about form, not function. They are the only people on a project with an opinion as to what color the bathrooms should be finished in.
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  98. @With the thoughts you'd be thinkin
    An engineer posted his analysis on the collapse, basically it seems they fucked up the tensioning of the cables that go in the concrete of the bottom of the bridge and other stuff contributed like moving supports.
    https://youtu.be/ioC61QW7SHQ
    https://youtu.be/KtiTm2dKLgU

    Even though the guy is irritating (to me) to listen to, the second vid seems to be onto something. The bridge collapse began exactly where the lift was located, where they were working. From the drawings he has, they were required to pre-tension the rods. This very well could be what led to the collapse. If the rods failed, they were probably under-sized for installation, if not for service. I’ve seen things like this happen.

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  99. J.Ross says: • Website
    @Lot
    Sounds like a bad place to work. My experience with construction was everyone appreciates a suggestion that improves quality or safety at minimal cost.

    You proposed designs changes on-site? Exactly how did that work? Why do I suspect you weren’t using an awful lot of hand tools at the time?

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  100. J.Ross says: • Website
    @Twodees Partain
    On a DoD job in a glass plant in the early '90s, I caught an error on the electrical print which had assigned 24 circuits in a clean room directly to a 200 amp. breaker in a distribution panel. Those circuits would have been properly fed from a 200 amp. sub-panel, but the sub-panel was left out of the schematic page AND the blueprint.

    The way I found the error was seeing a wire pulling crew bundling 8, 10 and 12 gauge wire to be pulled into the distribution panel in a single conduit. It seemed that the crew that roughed in the clean room's circuits noticed that there was no sub-panel, but they somehow failed to give a shit and just listed all the branch circuit wiring to be pulled into the DP via a 2" conduit that arrived at the outside of the clean room.

    The engineers have a saying: "A mistake can be fixed with an eraser. A fuckup requires a jackhammer". That particular fuckup needed a little more finesse than a jackhammer would have provided, but the principle still holds.

    Those are electricians, though. I want to believe that an electrician or a plumber would get attention. You ignore an electrician, you’ll get attention from the fire department.

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    • Replies: @Twodees Partain
    The engineers involved in the process, the E/M designer, their supervision/oversight engineers, the inspecting engineers on the architect's team, and everyone else who was involved in getting the design approved and put into production allowed the mistake to pass and it took a journeyman electrician (me) to start the process of getting a design change on-site started to correct the mistake.

    About plumbers and electricians, it has always been a wonder to me how DIY homeowners are more willing to attempt electrical repairs than plumbing repairs. If they make a mistake in their plumbing, they'll get water damage and/or a mess to clean up. If they make a mistake with their electrical system, they could get a house fire (as you mentioned) or someone may be killed by electrocution.
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  101. J.Ross says: • Website
    @Charles Pewitt
    A giant bolt made of the finest steel screwed into a steel bracket embedded in a massively heavy cement ceiling tile in a tunnel?

    No way! Just epoxy that bastard in there and let God and gravity sort it out!

    Good enough for government work! Print up the cash and watch the construction scams crash.

    https://twitter.com/ArtHennessey/status/974462908557090816

    A good theme to follow if you haven’t noticed it already: leftists depend on denying the reality of evil. The idea that a person would indulge in ultimately murderous venality is not a danger to be guarded against with morality and ethics, it’s not a historically evidenced event to look into, it’s “too horrible to contemplate.” All the other brilliant leftoid proposals for society make sense if you simply forget how horrible humans can be.

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  102. 1. realbigse may be knowledgeable, but he is also a dick… this is NOT a review board by PEs, it is a bunch of knuckleheads standing around a water cooler speculating on stuff, 99% of which we don’t have expertise in… its called being a human bean, try it sometime, realbigah…
    .
    2. another poster mentioned about lax construction practices, particularly concerning concrete… it is NOT uncommon for contractors to ‘water down’ their concrete to make it ‘flow’ easily when ‘poured’… as my old concrete design teacher said, ‘concrete is to be PLACED, not poured’… water not only weakens the concrete itself, but can easily lead to the aggregate segregating, which makes it weaker, vicious cycle ensues…
    .
    3. again, as pointed out by other posters and is very important, concrete does not ‘cure’ by drying out, it is a chemical process called hydration which -theoretically- continues forever in the presence of water…
    .
    4. lastly, THE BEST (whatever that is) design in the world for whatever purpose, can be totally fubar’ed in the construction process if specs are not followed, cheaper materials are substituted, bad construction techniques are used, etc…
    .
    really and truly, probably just because we generally over-design stuff with large factors of safety that a LOT more shit doesn’t fall down go boom…

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    • Replies: @ThreeCranes
    True what you say. Having worked on many civil engineering projects I can say that the on-site inspector is one of the key players in the game. He must be honest, he must have integrity and be strong-willed enough to speak up to the contractor/builder if he sees something being done that does not conform to the plans.

    His is one of those in-between, go-between positions that the European trade-school colleges produce but which aren't cultivated in America's educational system. An inspector must be intelligent enough to read blueprints and understand basic sound engineering, experienced enough in the field to recognize good from bad practice and affable enough with blue collar, working-class, construction guys to get along with them on a daily/hourly basis.

    A crooked or lax inspector can doom a project. However, contractors who want repeat contracts (and that's most of them) are generally--but not always--conscientious.

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  103. @ThreeCranes
    It's not an exaggeration to say that most structures built by human hands are boxes.

    A unibody automobile is a box. A ship is a long shoebox and the stresses in the hull are analyzed as such. Of course, your house, furniture (including the four-legged chair at your dining room table) are boxes. A chimney or skyscraper is just an upright box. A cylinder, like an airplane fuselage, can be thought of as a circular box. The walls of your house are thin-section boxes.

    If you want to improve your home project instantly, put a lid on it. Close it up. Add an access hatch. Many problems with amateur construction come from not boxing something in. I see this mistake all the time. Here's an example: a 2x4 framed wall with 3/4" ply sheathing on one face is much weaker than the same faced on both sides with 3/8" ply, even though they weigh the same. Grab one side of a rigid suitcase that is lying open and you can easily twist it with your hands, closed it's got integrity.

    Many amateurs believe that by substituting weight for integral form that they can make something stronger. This has to be carefully engineered. Anything cantilevered--that is, projecting out into space from one end--must be very carefully designed. A convertible automobile must have special bracing because the roof, the top of the box, is not there to provide integral rigidity. Coupes require thickened pillars front and rear, to resist racking. And so on.

    Everything is a series of beams, in theory. All stress analysis (except finite element analysis) is based on structural beam formulas. A box is simply a way of distributing forces.

    The basic formula for stress is P=S/A, where P is resultant stress, S is force, and A is area. A small force on a small area results in an acceptable stress. A small force on a large area results in little stress. A large stress on a small area results in a high stress. “Area” is cross-sectional area, typically steel. The properties of the steel (or concrete, or wood, etc.) are part of the long equation. So your statement about using “weight”, by which you mean “more steel” or whatever, is absolutely wrong, because “weight” is a key factor in stress, and you most certainly can reduce stress by adding more of it.

    This is true, I’m sure, for ships and cars, as they are basically steel structures. It’s most definitely the case for actual structures, like buildings and bridges (and pipe lines).

    Now, what you can say is that by properly distributing those forces you can use smaller components, which is true. The building frames we design today are much, much lighter than those we designed 30 years ago.

    A cantilevered beam in practical use is a rare thing. This is simply because all the forces are multiplied by the length of the cantilever; the “fat man standing on it” analogy. A 200 lb. man standing on the end of a 10 ft. cantilever creates 2000 ft. lbs of moment (bending stress) on the beam support at the other end. A 300 lb. man will put 3000 ft. lbs of stress on the support. And we’re not even accounting for the shear stresses. 2000 lbs. on a W12 x 32 isn’t much, but on a 3 x 3 x 1/4 angle, it’s probably going to fail. That’s why there is framing, cross-bracing, etc., in order to distribute loads. Of course, this is cartoon level engineering, and the structural/civil guys will probably pick at me about this.

    The place one most often sees cantilevers are building fronts, weather protection over entrances, and those are designed by architects, and no self-respecting structural engineer would do that, but architects are all about form, not function. They are the only people on a project with an opinion as to what color the bathrooms should be finished in.

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    • Replies: @Achmed E. Newman
    If you are talking stress, Rebel. there are 3 main types of loading. Axial (σ=F/A), that is, simple tension or compression (ignoring failure due to buckling for the moment) is the simplest to analyze. Then there are bending and torsion. I'm leaving out contact stress, which is, BTW, the only type I know for which stresses are not linear with loading, but it's probably very familiar to civil engineers who build roads.

    So your statement about using “weight”, by which you mean “more steel” or whatever, is absolutely wrong, because “weight” is a key factor in stress, and you most certainly can reduce stress by adding more of it.
     
    What 3-cranes was saying about this, in his example about a wall, is correct - you can have plenty of material in the wrong place, lowering the stresses in those location to way under acceptable values (taking into account cyclic loading, thermal effects, and safety factors, of course). It's a waste then, and if you're just counting amount of material, it could have been placed elsewhere to strengthen the structure.

    A structure or machine should be designed against failure with the optimum amount and type of material to resist the stress field throughout. This is subject to cost constraints and other engineering factors like unacceptable deformations (bending, twisting, even axial) and even thermo/heat transfer stuff some projects,

    I'll give 2 bending examples now. Take one 2x6 used to support a roof. Which way will you lay it against the vertical load, 6" (OK, 5.5" now) side vertically , or horizontally? This one is obvious, right?

    Here's a cooler one - you want to reinforce a 4 x 4 with another 2 x 4 under the same vertical loading. Would you put the 2x4 alongside the 4x4, or on top of it, room permitting? The stronger beam would be with the 2x4 on top or bottom, as the area moment of inertia goes as the cube of height (load direction) and linearly with width. Here's the cool part - Let's assume you take this to heart and put the 2x4 on top (or bottom) of the 4x4. Would you glue the pieces together before putting the load on, or after or does it matter?

    I don't give numbers here, so I'd like to read what the engineers on here have to say. I got all night ....
    , @Achmed E. Newman

    Of course, this is cartoon level engineering, and the structural/civil guys will probably pick at me about this.
     
    Not cartoon level, but just the stuff can't be learned via blog comments back and forth. There's a whole lot to it, and you must get to the math and do problems to understand.
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  104. rogue-one says:
    @anonymous
    Was this catastrophe an example of "raggedy work"?

    As the Chicago Tribune reported May 6, 2017:

    Obama said his foundation would not hire firms [to construct his library] just because they are run by African-Americans, Latinos or women.

    "If we have to choose between somebody who is not a woman- or minority-owned vendor and who does really great work and is going to make this whole thing terrific, and somebody who's raggedy, we will choose the folks who do the work," Obama said to a loud roar of laughs.

    ...That remark drew a joke from [Mayor] Emanuel. ... when the president made his statement about raggedy businesses, the mayor said, '... do you really think I could say that at the City Council?'

    And yet, Mr. Obama during his tenure did everything to create racial spoils systems including in his favored constituency of tech firms. The school discipline wasn’t about “doing the work”, it was about “equity” and “diversity”, as was everything else.

    Obama 2017: Competence for me, diversity for thee.

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  105. Stop blaming the AA-hire’s testosterone-deficient state for the bad design. Having support on two far away ends and nothing in the middle wouldn’t work for sewing or a layer cake either.

    Stupid has no gender.

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  106. @RebelWriter
    Everything is a series of beams, in theory. All stress analysis (except finite element analysis) is based on structural beam formulas. A box is simply a way of distributing forces.

    The basic formula for stress is P=S/A, where P is resultant stress, S is force, and A is area. A small force on a small area results in an acceptable stress. A small force on a large area results in little stress. A large stress on a small area results in a high stress. "Area" is cross-sectional area, typically steel. The properties of the steel (or concrete, or wood, etc.) are part of the long equation. So your statement about using "weight", by which you mean "more steel" or whatever, is absolutely wrong, because "weight" is a key factor in stress, and you most certainly can reduce stress by adding more of it.

    This is true, I'm sure, for ships and cars, as they are basically steel structures. It's most definitely the case for actual structures, like buildings and bridges (and pipe lines).

    Now, what you can say is that by properly distributing those forces you can use smaller components, which is true. The building frames we design today are much, much lighter than those we designed 30 years ago.

    A cantilevered beam in practical use is a rare thing. This is simply because all the forces are multiplied by the length of the cantilever; the "fat man standing on it" analogy. A 200 lb. man standing on the end of a 10 ft. cantilever creates 2000 ft. lbs of moment (bending stress) on the beam support at the other end. A 300 lb. man will put 3000 ft. lbs of stress on the support. And we're not even accounting for the shear stresses. 2000 lbs. on a W12 x 32 isn't much, but on a 3 x 3 x 1/4 angle, it's probably going to fail. That's why there is framing, cross-bracing, etc., in order to distribute loads. Of course, this is cartoon level engineering, and the structural/civil guys will probably pick at me about this.

    The place one most often sees cantilevers are building fronts, weather protection over entrances, and those are designed by architects, and no self-respecting structural engineer would do that, but architects are all about form, not function. They are the only people on a project with an opinion as to what color the bathrooms should be finished in.

    If you are talking stress, Rebel. there are 3 main types of loading. Axial (σ=F/A), that is, simple tension or compression (ignoring failure due to buckling for the moment) is the simplest to analyze. Then there are bending and torsion. I’m leaving out contact stress, which is, BTW, the only type I know for which stresses are not linear with loading, but it’s probably very familiar to civil engineers who build roads.

    So your statement about using “weight”, by which you mean “more steel” or whatever, is absolutely wrong, because “weight” is a key factor in stress, and you most certainly can reduce stress by adding more of it.

    What 3-cranes was saying about this, in his example about a wall, is correct – you can have plenty of material in the wrong place, lowering the stresses in those location to way under acceptable values (taking into account cyclic loading, thermal effects, and safety factors, of course). It’s a waste then, and if you’re just counting amount of material, it could have been placed elsewhere to strengthen the structure.

    A structure or machine should be designed against failure with the optimum amount and type of material to resist the stress field throughout. This is subject to cost constraints and other engineering factors like unacceptable deformations (bending, twisting, even axial) and even thermo/heat transfer stuff some projects,

    I’ll give 2 bending examples now. Take one 2×6 used to support a roof. Which way will you lay it against the vertical load, 6″ (OK, 5.5″ now) side vertically , or horizontally? This one is obvious, right?

    Here’s a cooler one – you want to reinforce a 4 x 4 with another 2 x 4 under the same vertical loading. Would you put the 2×4 alongside the 4×4, or on top of it, room permitting? The stronger beam would be with the 2×4 on top or bottom, as the area moment of inertia goes as the cube of height (load direction) and linearly with width. Here’s the cool part – Let’s assume you take this to heart and put the 2×4 on top (or bottom) of the 4×4. Would you glue the pieces together before putting the load on, or after or does it matter?

    I don’t give numbers here, so I’d like to read what the engineers on here have to say. I got all night ….

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    • Replies: @RebelWriter
    You typed this just to hear the sound of your fingers on the keys, I suspect. No worries, I do the same thing sometimes. A lot of times, in fact.

    I was a stress analyst for 20 years. I used simple beam formulas by hand for what we refer to as visual review, but most of the work I did was on stress analysis software. When I started we ran it on an IBM remote terminal, and the analysis ran on an IBM mainframe. The software was called Pipeline. I believe it was written by Westinghouse. Things got better very quickly as computers became more advanced. I preferred Caesar II (and still would), but also used Triflex and AutoPipe.

    I was trained by a very interesting fellow who did simultaneous equations for fun, the way some people do crossword puzzles. He started in pipe stress at Fluor in Irvine in 1968. He's a very highly regarded stress engineer. He was, in fact, the man who pointed out a major flaw in Caesar that the engineers and developers missed. As briefly as I can describe it, a line could grow in the vertical and lift off a support, but this wouldn't be taken into account in the constant (dead weight) analysis. The ASME requires piping acceptable stresses in constant and thermal. The constant analysis was wrong, because the support would be holding up the pipe in that run when, in fact, it would grow off in the thermal. He came up with a fix, which was to remove the support in the constant analysis if it grew off in the thermal, whether it was left in the design or not. I've had to prove this to many experienced stress analysts.

    I cut my teeth on continuous polymerization plants, mostly for DuPont. These were jacketed piping systems operating at around 600 degrees F (it varied at different points in the process) and from 50 to 2500 psi. Most of the equipment was likewise jacketed, except the high pressure pumps, which had heating pads on them.

    Jacketed pipe is a pipe within a pipe. The core piping is where the product flows, and the annulus of the jacket was filled with vaporized hot oil at 630 F and 50 psi. The 50 psi is why they used hot oil rather than steam. The jacketed piping was too stiff to bend, and too hot not to expand a lot. The solution was to design the system so that it could be heated up, with break flanges at certain points, and grow into place. It's pretty cool to watch two 24" 2500 lb flanges grow toward each other, and watch the crews slip the gasket into place, then bolt them up.

    I've also done analysis for power plants, which is B31.1, as opposed to B31.3, which I used for process piping design. I've never done analysis on the main steam, hot reheat, or cold reheat piping systems, though. That's highly specialized work, and only a few companies do it. Most of my work was on auxiliary steam and condensate systems.

    I have been the lead stress analyst on several projects, the "parking garage" project was the largest. On that project I had a team of 8 engineers working 60 hours a week. It was a new design, and by intent grew up from the bottom floor. It had 7 floors of an average of 20 ft. in height. By the time we got to the top, the hot oil vapor lines were growing up more than 7" from their cold position. We had equipment operating at different temperatures hard bolted together, and had to have many nozzles analyed using FEA from a specialty firm. It was a very challenging project.

    I've also done analysis for piping systems built in seismic zones, including in San Francisco, and was trained in dynamic analysis, though I never used it. What we, and most firms, do is use a factored seismic load in a separate run that's based on several variables to imitate the imposed load resultant from an earthquake. Dynamic analysis is still the only way to analyze harmonic analysis for (possible) natural frequencies. I've always found that especially interesting. The Tacoma Narrows bridge collapse is an example of what natural frequency distortion can do.

    As to your 2x4 analogy, I'm sorry to tell you that to a structural engineer or stress analyst, either way is exactly the same. I've never heard of a residential home being analyzed, but if it were, there would be no difference; except there may be an exception to consider in how they are joined. Structural analysis and piping stress analysis use the same structural beam formulas (though we use different software). I wrote out the formula for stress already. Look at it again. Force divided by Area. Either method of joining the two piece of wood would double the cross-sectional area. The two pieces of wood are nothing until they're joined to the structure. Two side by side would be more easily connected without designing a special connection top and bottom. And they would provide exactly the same amount of resistance to forces.

    I know you want to argue with me, and you'll very likely post a longer argument. Go ahead. Feel free. I'm comfy.

    , @ThreeCranes
    I would glue them together before the load is applied, otherwise, what's the point? As you say, the key dimension is depth and if the load is applied first, the two don't behave as one unit.

    But before I put them together, I'd be sure to place them so the apex of whatever crown they have is up, arch-like. Concrete bridge sections and semi-trailers are pre-arched in this way which is obvious when you pass an empty, unloaded trailer on the interstate.

    On the other hand, leaf springs aren't held together rigidly, but that's so any shock load is taken up progressively.

    And on the third hand, large, deep section, glue-lam beams used to span churches, arenas and the like certainly are glued together before any force is applied.
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  107. @RebelWriter
    Everything is a series of beams, in theory. All stress analysis (except finite element analysis) is based on structural beam formulas. A box is simply a way of distributing forces.

    The basic formula for stress is P=S/A, where P is resultant stress, S is force, and A is area. A small force on a small area results in an acceptable stress. A small force on a large area results in little stress. A large stress on a small area results in a high stress. "Area" is cross-sectional area, typically steel. The properties of the steel (or concrete, or wood, etc.) are part of the long equation. So your statement about using "weight", by which you mean "more steel" or whatever, is absolutely wrong, because "weight" is a key factor in stress, and you most certainly can reduce stress by adding more of it.

    This is true, I'm sure, for ships and cars, as they are basically steel structures. It's most definitely the case for actual structures, like buildings and bridges (and pipe lines).

    Now, what you can say is that by properly distributing those forces you can use smaller components, which is true. The building frames we design today are much, much lighter than those we designed 30 years ago.

    A cantilevered beam in practical use is a rare thing. This is simply because all the forces are multiplied by the length of the cantilever; the "fat man standing on it" analogy. A 200 lb. man standing on the end of a 10 ft. cantilever creates 2000 ft. lbs of moment (bending stress) on the beam support at the other end. A 300 lb. man will put 3000 ft. lbs of stress on the support. And we're not even accounting for the shear stresses. 2000 lbs. on a W12 x 32 isn't much, but on a 3 x 3 x 1/4 angle, it's probably going to fail. That's why there is framing, cross-bracing, etc., in order to distribute loads. Of course, this is cartoon level engineering, and the structural/civil guys will probably pick at me about this.

    The place one most often sees cantilevers are building fronts, weather protection over entrances, and those are designed by architects, and no self-respecting structural engineer would do that, but architects are all about form, not function. They are the only people on a project with an opinion as to what color the bathrooms should be finished in.

    Of course, this is cartoon level engineering, and the structural/civil guys will probably pick at me about this.

    Not cartoon level, but just the stuff can’t be learned via blog comments back and forth. There’s a whole lot to it, and you must get to the math and do problems to understand.

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  108. @art guerrilla
    1. realbigse may be knowledgeable, but he is also a dick... this is NOT a review board by PEs, it is a bunch of knuckleheads standing around a water cooler speculating on stuff, 99% of which we don't have expertise in... its called being a human bean, try it sometime, realbigah...
    .
    2. another poster mentioned about lax construction practices, particularly concerning concrete... it is NOT uncommon for contractors to 'water down' their concrete to make it 'flow' easily when 'poured'... as my old concrete design teacher said, 'concrete is to be PLACED, not poured'... water not only weakens the concrete itself, but can easily lead to the aggregate segregating, which makes it weaker, vicious cycle ensues...
    .
    3. again, as pointed out by other posters and is very important, concrete does not 'cure' by drying out, it is a chemical process called hydration which -theoretically- continues forever in the presence of water...
    .
    4. lastly, THE BEST (whatever that is) design in the world for whatever purpose, can be totally fubar'ed in the construction process if specs are not followed, cheaper materials are substituted, bad construction techniques are used, etc...
    .
    really and truly, probably just because we generally over-design stuff with large factors of safety that a LOT more shit doesn't fall down go boom...

    True what you say. Having worked on many civil engineering projects I can say that the on-site inspector is one of the key players in the game. He must be honest, he must have integrity and be strong-willed enough to speak up to the contractor/builder if he sees something being done that does not conform to the plans.

    His is one of those in-between, go-between positions that the European trade-school colleges produce but which aren’t cultivated in America’s educational system. An inspector must be intelligent enough to read blueprints and understand basic sound engineering, experienced enough in the field to recognize good from bad practice and affable enough with blue collar, working-class, construction guys to get along with them on a daily/hourly basis.

    A crooked or lax inspector can doom a project. However, contractors who want repeat contracts (and that’s most of them) are generally–but not always–conscientious.

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  109. @Hibernian
    "Gore later called Penelas 'the single most treacherous and dishonest person' he dealt with during his presidential run."

    Takes one to know one.

    It appears that Penelas was one of the few politicians who ever stood on principle in their lives.

    http://www.miaminewtimes.com/news/the-dead-end-kid-6354322

    A few years ago, the notion of Penelas distancing himself from Gore and the Democrats was unthinkable. Through the first seven years of the Clinton-Gore administration, Penelas never missed an opportunity to be seen with the president and vice president. When Gore began his campaign for the presidency, Penelas hung so tightly to the vice president’s coattails he could have been arrested for stalking.

    In 1998, at the height of the impeachment scandal surrounding Clinton, Penelas unexpectedly met with Gore in Washington, leading some to speculate that Gore was preparing to tap Penelas for a cabinet post in the event Clinton was forced to resign. The mayor relished such rumors. “I’ve heard it on Spanish radio, from people in the street,” he told the Miami Herald at the time. “I’m very flattered by it.”

    A year later he was no less flattered when Newsweek claimed he was included on a list of possible running mates being considered by the Gore campaign, a rumor Penelas’s own minions had been eagerly spreading for weeks before the magazine’s article appeared. In response to the story, Penelas proudly declared he was ready to serve “in any capacity.” At the very least it seemed certain that if Gore were elected president, Penelas would be in line for a cabinet position. Conjecture leaned toward a post as secretary of housing and urban development.

    [...]

    Penelas’s political future began unraveling with the arrival of little Elian Gonzalez. Even before the April 22 raid on the home of the boy’s Miami relatives, Penelas believed the administration’s handling of the Elian affair had hindered him. The mayor’s now-infamous statement in front of the federal courthouse was a measure of his personal frustration with a Washington bureaucracy that didn’t seem appropriately sensitive to his local political needs.

    After Penelas personally attacked Clinton and threatened to hold the president and Attorney General Janet Reno responsible for any violent civil unrest in Miami, the president responded in kind: He froze out the mayor. According to one source close to Penelas, in the weeks following that defiant statement, Clinton refused to meet or talk with Penelas, despite repeated requests by the mayor.

    Politically speaking, the president essentially sent Penelas to bed without supper. He didn’t publicly humiliate the mayor or retaliate by trying to hold up federal funds intended for Miami-Dade. He simply spanked him.

    [...]

    In the weeks following the raid that removed Elian, Penelas’s own mayoral re-election campaign began moving into high gear. Perhaps not surprisingly he figured it was best for him to steer clear of Gore, and so he refused to attend any functions with the vice president. Although members of the Gore campaign had hoped Penelas would have shown more loyalty to the vice president, they understood he was in a tough election battle of his own.

    But there was an expectation among Democrats that after Penelas won his election, he would be free to help the vice president.

    [...]

    Martinez recalls that he and Penelas were supposed to host a joint press conference in support of Gore on October 18. Both the date and the time had been selected to accommodate Penelas’s schedule. Yet Penelas failed to show. Later that day he boarded a plane for his vacation in Spain. “When the going gets tough, he just hides,” Martinez says derisively. “Alex is weak; he doesn’t have a backbone. He is just a wimp. He only cares for Alex Penelas and doesn’t care for anyone else.”

    Penelas campaign advisor Ric Katz claims the mayor never committed to attending that press conference. Martinez disagrees. Lobbyist Korge floats this comical excuse: Penelas was unable to attend the October 18 event because he had to get home and pack for his vacation. Katz, however, did promise that when Penelas returned from Spain at the end of October he would actively barnstorm for the vice president and be “visible” in the crucial closing days. Despite that promise Penelas remained virtually invisible. Even during last week’s star-studded midnight rally on the sands of Miami Beach — the very last day of the campaign — Penelas was a no-show. “It was just very late at night,” sputters Penelas spokesman Juan Mendieta.

    According to pollster Schroth, Gore ended up receiving only 22 percent of the Cuban-American vote, about half of what Clinton garnered in 1996.

    Incidentally, Jim DeFede, the author of this piece, was fired from the Miami Herald in 2005 for illegally recording a phone conversation with the disgraced Arthur Teele, at one time the most powerful black in Miami. Teele was calling from a payphone in the Herald lobby.

    (This conversation took place the day before the Miami New Times – the “alternative” weekly where DeFede got his start – was set to publish a lengthy piece about Teele’s corruption, drug use, and fondness for callboys.)

    After hanging up the phone, Teele took a gun out of his pocket and blew his brains out. The next morning, Herald readers were treated to a huge front-page picture of his blood-soaked corpse.

    DeFede, who weighs at least 400 pounds, now works for a local television station. Here he is seen looking positively svelte while interviewing Marco the Rube:

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  110. @Lot
    "Is that a good design?"

    No. It was such an ugly design it provoked the wrath of God. Architecture must either be humble or if grandiose should honor Him the way Notre Dame Cathedral does.

    This was an ugly post modern attempt to make a simple pedestrian bridge look like a suspension bridge marooned on land. Looked like some crap Frank Gehry would design if you made him stick to a tight budget.

    https://pbs.twimg.com/media/C_EeytwXcAA0tRH.jpg

    Pride goeth before destruction, and an haughty spirit before a fall.

    “Designed as a cable-supported bridge, the project was a collaboration between MCM Construction, a prominent Miami-based contractor, and FIGG Bridge Design, based in Tallahassee. FIGG is responsible for the iconic Sunshine Skyway Bridge across Tampa Bay.”

    Here’s a picture of the Sunshine Skyway Bridge (in which, as someone above said, part of the load IS carried by the cables and towers).

    As you can see, a beautiful bridge and one which the pedestrian bridge was obviously trying to echo, aesthetically anyways.

    Read More
    • Replies: @CCZ
    The MCM-Figg FIU Pedestrian Bridge Design Submission and Preliminary Plans:

    http://facilities.fiu.edu/projects/BT_904/MCM_FIGG_Proposal_for_FIU_Pedestrian_Bridge_9-30-2015.pdf

    , @Rosamond Vincy
    And that's the problem. The FIU engineers were looking at form, not function.
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  111. @Pericles
    I thought P.J. O'Rourke's Parliament of Whores was extremely funny, but it clearly belongs to a very different era. So does O'Rourke, come to think of it.

    Believe it or not, back when I read his stuff, I thought that title, Parliament of Whores, was a bit harsh. Now, I think it wouldn’t be going far enough as a good description of the US Congress.

    Read More
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  112. CCZ says:
    @ThreeCranes
    "Designed as a cable-supported bridge, the project was a collaboration between MCM Construction, a prominent Miami-based contractor, and FIGG Bridge Design, based in Tallahassee. FIGG is responsible for the iconic Sunshine Skyway Bridge across Tampa Bay."

    Here's a picture of the Sunshine Skyway Bridge (in which, as someone above said, part of the load IS carried by the cables and towers).

    https://i.pinimg.com/736x/3b/97/27/3b972790329bb303156cd704fd382a11.jpg

    http://images.fineartamerica.com/images/artworkimages/mediumlarge/1/sunshine-skyway-bridge-jonathan-sabin.jpg

    As you can see, a beautiful bridge and one which the pedestrian bridge was obviously trying to echo, aesthetically anyways.

    The MCM-Figg FIU Pedestrian Bridge Design Submission and Preliminary Plans:

    http://facilities.fiu.edu/projects/BT_904/MCM_FIGG_Proposal_for_FIU_Pedestrian_Bridge_9-30-2015.pdf

    Read More
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  113. @ThreeCranes
    "Designed as a cable-supported bridge, the project was a collaboration between MCM Construction, a prominent Miami-based contractor, and FIGG Bridge Design, based in Tallahassee. FIGG is responsible for the iconic Sunshine Skyway Bridge across Tampa Bay."

    Here's a picture of the Sunshine Skyway Bridge (in which, as someone above said, part of the load IS carried by the cables and towers).

    https://i.pinimg.com/736x/3b/97/27/3b972790329bb303156cd704fd382a11.jpg

    http://images.fineartamerica.com/images/artworkimages/mediumlarge/1/sunshine-skyway-bridge-jonathan-sabin.jpg

    As you can see, a beautiful bridge and one which the pedestrian bridge was obviously trying to echo, aesthetically anyways.

    And that’s the problem. The FIU engineers were looking at form, not function.

    Read More
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  114. @Achmed E. Newman
    If you are talking stress, Rebel. there are 3 main types of loading. Axial (σ=F/A), that is, simple tension or compression (ignoring failure due to buckling for the moment) is the simplest to analyze. Then there are bending and torsion. I'm leaving out contact stress, which is, BTW, the only type I know for which stresses are not linear with loading, but it's probably very familiar to civil engineers who build roads.

    So your statement about using “weight”, by which you mean “more steel” or whatever, is absolutely wrong, because “weight” is a key factor in stress, and you most certainly can reduce stress by adding more of it.
     
    What 3-cranes was saying about this, in his example about a wall, is correct - you can have plenty of material in the wrong place, lowering the stresses in those location to way under acceptable values (taking into account cyclic loading, thermal effects, and safety factors, of course). It's a waste then, and if you're just counting amount of material, it could have been placed elsewhere to strengthen the structure.

    A structure or machine should be designed against failure with the optimum amount and type of material to resist the stress field throughout. This is subject to cost constraints and other engineering factors like unacceptable deformations (bending, twisting, even axial) and even thermo/heat transfer stuff some projects,

    I'll give 2 bending examples now. Take one 2x6 used to support a roof. Which way will you lay it against the vertical load, 6" (OK, 5.5" now) side vertically , or horizontally? This one is obvious, right?

    Here's a cooler one - you want to reinforce a 4 x 4 with another 2 x 4 under the same vertical loading. Would you put the 2x4 alongside the 4x4, or on top of it, room permitting? The stronger beam would be with the 2x4 on top or bottom, as the area moment of inertia goes as the cube of height (load direction) and linearly with width. Here's the cool part - Let's assume you take this to heart and put the 2x4 on top (or bottom) of the 4x4. Would you glue the pieces together before putting the load on, or after or does it matter?

    I don't give numbers here, so I'd like to read what the engineers on here have to say. I got all night ....

    You typed this just to hear the sound of your fingers on the keys, I suspect. No worries, I do the same thing sometimes. A lot of times, in fact.

    I was a stress analyst for 20 years. I used simple beam formulas by hand for what we refer to as visual review, but most of the work I did was on stress analysis software. When I started we ran it on an IBM remote terminal, and the analysis ran on an IBM mainframe. The software was called Pipeline. I believe it was written by Westinghouse. Things got better very quickly as computers became more advanced. I preferred Caesar II (and still would), but also used Triflex and AutoPipe.

    I was trained by a very interesting fellow who did simultaneous equations for fun, the way some people do crossword puzzles. He started in pipe stress at Fluor in Irvine in 1968. He’s a very highly regarded stress engineer. He was, in fact, the man who pointed out a major flaw in Caesar that the engineers and developers missed. As briefly as I can describe it, a line could grow in the vertical and lift off a support, but this wouldn’t be taken into account in the constant (dead weight) analysis. The ASME requires piping acceptable stresses in constant and thermal. The constant analysis was wrong, because the support would be holding up the pipe in that run when, in fact, it would grow off in the thermal. He came up with a fix, which was to remove the support in the constant analysis if it grew off in the thermal, whether it was left in the design or not. I’ve had to prove this to many experienced stress analysts.

    I cut my teeth on continuous polymerization plants, mostly for DuPont. These were jacketed piping systems operating at around 600 degrees F (it varied at different points in the process) and from 50 to 2500 psi. Most of the equipment was likewise jacketed, except the high pressure pumps, which had heating pads on them.

    Jacketed pipe is a pipe within a pipe. The core piping is where the product flows, and the annulus of the jacket was filled with vaporized hot oil at 630 F and 50 psi. The 50 psi is why they used hot oil rather than steam. The jacketed piping was too stiff to bend, and too hot not to expand a lot. The solution was to design the system so that it could be heated up, with break flanges at certain points, and grow into place. It’s pretty cool to watch two 24″ 2500 lb flanges grow toward each other, and watch the crews slip the gasket into place, then bolt them up.

    I’ve also done analysis for power plants, which is B31.1, as opposed to B31.3, which I used for process piping design. I’ve never done analysis on the main steam, hot reheat, or cold reheat piping systems, though. That’s highly specialized work, and only a few companies do it. Most of my work was on auxiliary steam and condensate systems.

    I have been the lead stress analyst on several projects, the “parking garage” project was the largest. On that project I had a team of 8 engineers working 60 hours a week. It was a new design, and by intent grew up from the bottom floor. It had 7 floors of an average of 20 ft. in height. By the time we got to the top, the hot oil vapor lines were growing up more than 7″ from their cold position. We had equipment operating at different temperatures hard bolted together, and had to have many nozzles analyed using FEA from a specialty firm. It was a very challenging project.

    I’ve also done analysis for piping systems built in seismic zones, including in San Francisco, and was trained in dynamic analysis, though I never used it. What we, and most firms, do is use a factored seismic load in a separate run that’s based on several variables to imitate the imposed load resultant from an earthquake. Dynamic analysis is still the only way to analyze harmonic analysis for (possible) natural frequencies. I’ve always found that especially interesting. The Tacoma Narrows bridge collapse is an example of what natural frequency distortion can do.

    As to your 2×4 analogy, I’m sorry to tell you that to a structural engineer or stress analyst, either way is exactly the same. I’ve never heard of a residential home being analyzed, but if it were, there would be no difference; except there may be an exception to consider in how they are joined. Structural analysis and piping stress analysis use the same structural beam formulas (though we use different software). I wrote out the formula for stress already. Look at it again. Force divided by Area. Either method of joining the two piece of wood would double the cross-sectional area. The two pieces of wood are nothing until they’re joined to the structure. Two side by side would be more easily connected without designing a special connection top and bottom. And they would provide exactly the same amount of resistance to forces.

    I know you want to argue with me, and you’ll very likely post a longer argument. Go ahead. Feel free. I’m comfy.

    Read More
    • Replies: @RebelWriter
    There is one caveat; the 4x4 would be equally strong in both directions, while the 2x8 would be weaker in one direction, and stronger in the other. This would be comparable to a tube or W section vs. a channel, all having the same cross-sectional area. I never considered this in piping analysis, but I also designed supports. I checked those by hand using simple beam formulas.
    , @Achmed E. Newman

    You typed this just to hear the sound of your fingers on the keys, I suspect.
     
    Nope, I typed it because you didn't seem like you knew quite what you were talking about. I have no doubt you're an engineer from what you just now wrote, but whether you did your bending calculations 20 years ago or not, you can't keep maintaining that stress just simply equals force/area. That is the DEFINITION of stress, not the relation for normal stress in bending (which may or may not be the larger stress over bending shear stresses). That relation is sigma = My/I, if you recall. "I", area moment of inertia is the key as far as the construction of the cross-section of the beam is concerned.

    I did mention that this was bending loading I was talking about, but maybe you missed that, so in that case, no argument here. Any yes, plenty of engineers do analysis of residential - modifications, say gutting of part of a house, can require new calculations, not solely reference to codes.
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  115. @Achmed E. Newman
    If you are talking stress, Rebel. there are 3 main types of loading. Axial (σ=F/A), that is, simple tension or compression (ignoring failure due to buckling for the moment) is the simplest to analyze. Then there are bending and torsion. I'm leaving out contact stress, which is, BTW, the only type I know for which stresses are not linear with loading, but it's probably very familiar to civil engineers who build roads.

    So your statement about using “weight”, by which you mean “more steel” or whatever, is absolutely wrong, because “weight” is a key factor in stress, and you most certainly can reduce stress by adding more of it.
     
    What 3-cranes was saying about this, in his example about a wall, is correct - you can have plenty of material in the wrong place, lowering the stresses in those location to way under acceptable values (taking into account cyclic loading, thermal effects, and safety factors, of course). It's a waste then, and if you're just counting amount of material, it could have been placed elsewhere to strengthen the structure.

    A structure or machine should be designed against failure with the optimum amount and type of material to resist the stress field throughout. This is subject to cost constraints and other engineering factors like unacceptable deformations (bending, twisting, even axial) and even thermo/heat transfer stuff some projects,

    I'll give 2 bending examples now. Take one 2x6 used to support a roof. Which way will you lay it against the vertical load, 6" (OK, 5.5" now) side vertically , or horizontally? This one is obvious, right?

    Here's a cooler one - you want to reinforce a 4 x 4 with another 2 x 4 under the same vertical loading. Would you put the 2x4 alongside the 4x4, or on top of it, room permitting? The stronger beam would be with the 2x4 on top or bottom, as the area moment of inertia goes as the cube of height (load direction) and linearly with width. Here's the cool part - Let's assume you take this to heart and put the 2x4 on top (or bottom) of the 4x4. Would you glue the pieces together before putting the load on, or after or does it matter?

    I don't give numbers here, so I'd like to read what the engineers on here have to say. I got all night ....

    I would glue them together before the load is applied, otherwise, what’s the point? As you say, the key dimension is depth and if the load is applied first, the two don’t behave as one unit.

    But before I put them together, I’d be sure to place them so the apex of whatever crown they have is up, arch-like. Concrete bridge sections and semi-trailers are pre-arched in this way which is obvious when you pass an empty, unloaded trailer on the interstate.

    On the other hand, leaf springs aren’t held together rigidly, but that’s so any shock load is taken up progressively.

    And on the third hand, large, deep section, glue-lam beams used to span churches, arenas and the like certainly are glued together before any force is applied.

    Read More
    • Replies: @ThreeCranes
    And of course, the best solution is to rip the 4x4 in half and attach one above and one below the 2x so as to create an I beam. That way you create a cross section with the greatest moment of Inertia i.e. most material distributed furthest from the neutral axis; this assumes that you want to handle some side loading as well as vertical loading. If you only need to handle vertical (as you're using it in your example) loading, then rip it in half and glue all three together edgeways.

    The carpenter trade publishes a table for roof rafter or floor joist dimensions. As you say, deeper goes up exponentially. A 2x12 is much more than 2x stiffer than a 2x6 (edgeways of course). I'm not going to take the trouble to look up just how much. As you know, this stiffness translates into how long a rafter or joist will span.

    , @Achmed E. Newman
    In my case, I was worried about additional loading, which I didn't state, so it was decision for me (this was just a very small project of my own). For illustration for non-engineers, I really should have just brought up whether the pieces should have been glued or not. The fact that they are made as one unit changes the situation from 3 beams basically acting as though they were next to each other, to one bigger one with a much greater I.

    You are right about the flat-bed trailers, and I think the convex arch moves the neutral axis toward the top, if I'm not mistaken. It may lower the shear stresses, but I'm not pulling the books out at this hour.

    Yes, the leaf-springs on trucks are an amazingly clever way to get varying stiffnesses.

    As far as your other comment (below this one), my 4x4's were not coming off at that point. Mine ended up a bit like an I-beam with a really thick web, because the outside (flange) pieces were 5/4" x 6's, which you probably know, are 1" thick by 5.5"

    Lastly, I didn't use the term "exponentially", because it's not - it's just simply I = bh**3 /12 for a rectangular shape. If you remember the parallel-axis theorem, this can take you a long way (you can work out I for any combination of rectangles in the X-section).

    Have a good night, all.
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  116. @RebelWriter
    You typed this just to hear the sound of your fingers on the keys, I suspect. No worries, I do the same thing sometimes. A lot of times, in fact.

    I was a stress analyst for 20 years. I used simple beam formulas by hand for what we refer to as visual review, but most of the work I did was on stress analysis software. When I started we ran it on an IBM remote terminal, and the analysis ran on an IBM mainframe. The software was called Pipeline. I believe it was written by Westinghouse. Things got better very quickly as computers became more advanced. I preferred Caesar II (and still would), but also used Triflex and AutoPipe.

    I was trained by a very interesting fellow who did simultaneous equations for fun, the way some people do crossword puzzles. He started in pipe stress at Fluor in Irvine in 1968. He's a very highly regarded stress engineer. He was, in fact, the man who pointed out a major flaw in Caesar that the engineers and developers missed. As briefly as I can describe it, a line could grow in the vertical and lift off a support, but this wouldn't be taken into account in the constant (dead weight) analysis. The ASME requires piping acceptable stresses in constant and thermal. The constant analysis was wrong, because the support would be holding up the pipe in that run when, in fact, it would grow off in the thermal. He came up with a fix, which was to remove the support in the constant analysis if it grew off in the thermal, whether it was left in the design or not. I've had to prove this to many experienced stress analysts.

    I cut my teeth on continuous polymerization plants, mostly for DuPont. These were jacketed piping systems operating at around 600 degrees F (it varied at different points in the process) and from 50 to 2500 psi. Most of the equipment was likewise jacketed, except the high pressure pumps, which had heating pads on them.

    Jacketed pipe is a pipe within a pipe. The core piping is where the product flows, and the annulus of the jacket was filled with vaporized hot oil at 630 F and 50 psi. The 50 psi is why they used hot oil rather than steam. The jacketed piping was too stiff to bend, and too hot not to expand a lot. The solution was to design the system so that it could be heated up, with break flanges at certain points, and grow into place. It's pretty cool to watch two 24" 2500 lb flanges grow toward each other, and watch the crews slip the gasket into place, then bolt them up.

    I've also done analysis for power plants, which is B31.1, as opposed to B31.3, which I used for process piping design. I've never done analysis on the main steam, hot reheat, or cold reheat piping systems, though. That's highly specialized work, and only a few companies do it. Most of my work was on auxiliary steam and condensate systems.

    I have been the lead stress analyst on several projects, the "parking garage" project was the largest. On that project I had a team of 8 engineers working 60 hours a week. It was a new design, and by intent grew up from the bottom floor. It had 7 floors of an average of 20 ft. in height. By the time we got to the top, the hot oil vapor lines were growing up more than 7" from their cold position. We had equipment operating at different temperatures hard bolted together, and had to have many nozzles analyed using FEA from a specialty firm. It was a very challenging project.

    I've also done analysis for piping systems built in seismic zones, including in San Francisco, and was trained in dynamic analysis, though I never used it. What we, and most firms, do is use a factored seismic load in a separate run that's based on several variables to imitate the imposed load resultant from an earthquake. Dynamic analysis is still the only way to analyze harmonic analysis for (possible) natural frequencies. I've always found that especially interesting. The Tacoma Narrows bridge collapse is an example of what natural frequency distortion can do.

    As to your 2x4 analogy, I'm sorry to tell you that to a structural engineer or stress analyst, either way is exactly the same. I've never heard of a residential home being analyzed, but if it were, there would be no difference; except there may be an exception to consider in how they are joined. Structural analysis and piping stress analysis use the same structural beam formulas (though we use different software). I wrote out the formula for stress already. Look at it again. Force divided by Area. Either method of joining the two piece of wood would double the cross-sectional area. The two pieces of wood are nothing until they're joined to the structure. Two side by side would be more easily connected without designing a special connection top and bottom. And they would provide exactly the same amount of resistance to forces.

    I know you want to argue with me, and you'll very likely post a longer argument. Go ahead. Feel free. I'm comfy.

    There is one caveat; the 4×4 would be equally strong in both directions, while the 2×8 would be weaker in one direction, and stronger in the other. This would be comparable to a tube or W section vs. a channel, all having the same cross-sectional area. I never considered this in piping analysis, but I also designed supports. I checked those by hand using simple beam formulas.

    Read More
    • Replies: @Achmed E. Newman

    ... the 4×4 would be equally strong in both directions, while the 2×8 would be weaker in one direction, and stronger in the other.
     
    These pieces of wood have a greater strength along the grain direction, sure, but that's not a factor in what we're talking about. Of course, the grain direction is the long dimension. Therefore, for any cross-section we're talking about, the strong direction strength (or max allowable stress, if you put it that way) will be the one considered for all normal stresses from the bending, while the weak 2 directions would be considered for strength for the shear stresses. Sound right?

    I don't see, therefore, that it'd matter much, as far as directional strength goes, but it's all about the Moment of Inertia about the axis of bending.

    Yes, wood is anisotropic, as compared to the pipes, W-sections, and all the metal stuff you've been working with.
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  117. @ThreeCranes
    I would glue them together before the load is applied, otherwise, what's the point? As you say, the key dimension is depth and if the load is applied first, the two don't behave as one unit.

    But before I put them together, I'd be sure to place them so the apex of whatever crown they have is up, arch-like. Concrete bridge sections and semi-trailers are pre-arched in this way which is obvious when you pass an empty, unloaded trailer on the interstate.

    On the other hand, leaf springs aren't held together rigidly, but that's so any shock load is taken up progressively.

    And on the third hand, large, deep section, glue-lam beams used to span churches, arenas and the like certainly are glued together before any force is applied.

    And of course, the best solution is to rip the 4×4 in half and attach one above and one below the 2x so as to create an I beam. That way you create a cross section with the greatest moment of Inertia i.e. most material distributed furthest from the neutral axis; this assumes that you want to handle some side loading as well as vertical loading. If you only need to handle vertical (as you’re using it in your example) loading, then rip it in half and glue all three together edgeways.

    The carpenter trade publishes a table for roof rafter or floor joist dimensions. As you say, deeper goes up exponentially. A 2×12 is much more than 2x stiffer than a 2×6 (edgeways of course). I’m not going to take the trouble to look up just how much. As you know, this stiffness translates into how long a rafter or joist will span.

    Read More
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  118. @RebelWriter
    You typed this just to hear the sound of your fingers on the keys, I suspect. No worries, I do the same thing sometimes. A lot of times, in fact.

    I was a stress analyst for 20 years. I used simple beam formulas by hand for what we refer to as visual review, but most of the work I did was on stress analysis software. When I started we ran it on an IBM remote terminal, and the analysis ran on an IBM mainframe. The software was called Pipeline. I believe it was written by Westinghouse. Things got better very quickly as computers became more advanced. I preferred Caesar II (and still would), but also used Triflex and AutoPipe.

    I was trained by a very interesting fellow who did simultaneous equations for fun, the way some people do crossword puzzles. He started in pipe stress at Fluor in Irvine in 1968. He's a very highly regarded stress engineer. He was, in fact, the man who pointed out a major flaw in Caesar that the engineers and developers missed. As briefly as I can describe it, a line could grow in the vertical and lift off a support, but this wouldn't be taken into account in the constant (dead weight) analysis. The ASME requires piping acceptable stresses in constant and thermal. The constant analysis was wrong, because the support would be holding up the pipe in that run when, in fact, it would grow off in the thermal. He came up with a fix, which was to remove the support in the constant analysis if it grew off in the thermal, whether it was left in the design or not. I've had to prove this to many experienced stress analysts.

    I cut my teeth on continuous polymerization plants, mostly for DuPont. These were jacketed piping systems operating at around 600 degrees F (it varied at different points in the process) and from 50 to 2500 psi. Most of the equipment was likewise jacketed, except the high pressure pumps, which had heating pads on them.

    Jacketed pipe is a pipe within a pipe. The core piping is where the product flows, and the annulus of the jacket was filled with vaporized hot oil at 630 F and 50 psi. The 50 psi is why they used hot oil rather than steam. The jacketed piping was too stiff to bend, and too hot not to expand a lot. The solution was to design the system so that it could be heated up, with break flanges at certain points, and grow into place. It's pretty cool to watch two 24" 2500 lb flanges grow toward each other, and watch the crews slip the gasket into place, then bolt them up.

    I've also done analysis for power plants, which is B31.1, as opposed to B31.3, which I used for process piping design. I've never done analysis on the main steam, hot reheat, or cold reheat piping systems, though. That's highly specialized work, and only a few companies do it. Most of my work was on auxiliary steam and condensate systems.

    I have been the lead stress analyst on several projects, the "parking garage" project was the largest. On that project I had a team of 8 engineers working 60 hours a week. It was a new design, and by intent grew up from the bottom floor. It had 7 floors of an average of 20 ft. in height. By the time we got to the top, the hot oil vapor lines were growing up more than 7" from their cold position. We had equipment operating at different temperatures hard bolted together, and had to have many nozzles analyed using FEA from a specialty firm. It was a very challenging project.

    I've also done analysis for piping systems built in seismic zones, including in San Francisco, and was trained in dynamic analysis, though I never used it. What we, and most firms, do is use a factored seismic load in a separate run that's based on several variables to imitate the imposed load resultant from an earthquake. Dynamic analysis is still the only way to analyze harmonic analysis for (possible) natural frequencies. I've always found that especially interesting. The Tacoma Narrows bridge collapse is an example of what natural frequency distortion can do.

    As to your 2x4 analogy, I'm sorry to tell you that to a structural engineer or stress analyst, either way is exactly the same. I've never heard of a residential home being analyzed, but if it were, there would be no difference; except there may be an exception to consider in how they are joined. Structural analysis and piping stress analysis use the same structural beam formulas (though we use different software). I wrote out the formula for stress already. Look at it again. Force divided by Area. Either method of joining the two piece of wood would double the cross-sectional area. The two pieces of wood are nothing until they're joined to the structure. Two side by side would be more easily connected without designing a special connection top and bottom. And they would provide exactly the same amount of resistance to forces.

    I know you want to argue with me, and you'll very likely post a longer argument. Go ahead. Feel free. I'm comfy.

    You typed this just to hear the sound of your fingers on the keys, I suspect.

    Nope, I typed it because you didn’t seem like you knew quite what you were talking about. I have no doubt you’re an engineer from what you just now wrote, but whether you did your bending calculations 20 years ago or not, you can’t keep maintaining that stress just simply equals force/area. That is the DEFINITION of stress, not the relation for normal stress in bending (which may or may not be the larger stress over bending shear stresses). That relation is sigma = My/I, if you recall. “I”, area moment of inertia is the key as far as the construction of the cross-section of the beam is concerned.

    I did mention that this was bending loading I was talking about, but maybe you missed that, so in that case, no argument here. Any yes, plenty of engineers do analysis of residential – modifications, say gutting of part of a house, can require new calculations, not solely reference to codes.

    Read More
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  119. @RebelWriter
    There is one caveat; the 4x4 would be equally strong in both directions, while the 2x8 would be weaker in one direction, and stronger in the other. This would be comparable to a tube or W section vs. a channel, all having the same cross-sectional area. I never considered this in piping analysis, but I also designed supports. I checked those by hand using simple beam formulas.

    … the 4×4 would be equally strong in both directions, while the 2×8 would be weaker in one direction, and stronger in the other.

    These pieces of wood have a greater strength along the grain direction, sure, but that’s not a factor in what we’re talking about. Of course, the grain direction is the long dimension. Therefore, for any cross-section we’re talking about, the strong direction strength (or max allowable stress, if you put it that way) will be the one considered for all normal stresses from the bending, while the weak 2 directions would be considered for strength for the shear stresses. Sound right?

    I don’t see, therefore, that it’d matter much, as far as directional strength goes, but it’s all about the Moment of Inertia about the axis of bending.

    Yes, wood is anisotropic, as compared to the pipes, W-sections, and all the metal stuff you’ve been working with.

    Read More
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  120. @ThreeCranes
    I would glue them together before the load is applied, otherwise, what's the point? As you say, the key dimension is depth and if the load is applied first, the two don't behave as one unit.

    But before I put them together, I'd be sure to place them so the apex of whatever crown they have is up, arch-like. Concrete bridge sections and semi-trailers are pre-arched in this way which is obvious when you pass an empty, unloaded trailer on the interstate.

    On the other hand, leaf springs aren't held together rigidly, but that's so any shock load is taken up progressively.

    And on the third hand, large, deep section, glue-lam beams used to span churches, arenas and the like certainly are glued together before any force is applied.

    In my case, I was worried about additional loading, which I didn’t state, so it was decision for me (this was just a very small project of my own). For illustration for non-engineers, I really should have just brought up whether the pieces should have been glued or not. The fact that they are made as one unit changes the situation from 3 beams basically acting as though they were next to each other, to one bigger one with a much greater I.

    You are right about the flat-bed trailers, and I think the convex arch moves the neutral axis toward the top, if I’m not mistaken. It may lower the shear stresses, but I’m not pulling the books out at this hour.

    Yes, the leaf-springs on trucks are an amazingly clever way to get varying stiffnesses.

    As far as your other comment (below this one), my 4×4′s were not coming off at that point. Mine ended up a bit like an I-beam with a really thick web, because the outside (flange) pieces were 5/4″ x 6′s, which you probably know, are 1″ thick by 5.5″

    Lastly, I didn’t use the term “exponentially”, because it’s not – it’s just simply I = bh**3 /12 for a rectangular shape. If you remember the parallel-axis theorem, this can take you a long way (you can work out I for any combination of rectangles in the X-section).

    Have a good night, all.

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  121. Last thing, here, back to Dave Barry:

    “Ain’t nobody masterminded shit,” the prisoner shouted back.

    I guess this quote was original, but Mr. Barry sure got this right, which makes it “funny cause it’s true” funny. That’s exactly the way it would have been said, and this alone cracked me up.

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  122. When this happened I thought that affirmative action was probably to blame. Turns out I was correct.

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  123. @Pericles
    I thought P.J. O'Rourke's Parliament of Whores was extremely funny, but it clearly belongs to a very different era. So does O'Rourke, come to think of it.

    So does O’Rourke, come to think of it.

    He said he voted for HRC, so f**k him.

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    • Replies: @Charles Erwin Wilson II

    He said he voted for HRC, so f**k him.
     
    Agree.
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  124. @J.Ross
    Those are electricians, though. I want to believe that an electrician or a plumber would get attention. You ignore an electrician, you'll get attention from the fire department.

    The engineers involved in the process, the E/M designer, their supervision/oversight engineers, the inspecting engineers on the architect’s team, and everyone else who was involved in getting the design approved and put into production allowed the mistake to pass and it took a journeyman electrician (me) to start the process of getting a design change on-site started to correct the mistake.

    About plumbers and electricians, it has always been a wonder to me how DIY homeowners are more willing to attempt electrical repairs than plumbing repairs. If they make a mistake in their plumbing, they’ll get water damage and/or a mess to clean up. If they make a mistake with their electrical system, they could get a house fire (as you mentioned) or someone may be killed by electrocution.

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    • Replies: @JMcG
    Blame the DYI books and YouTube. It is appalling what people will attempt to do with electricity in their homes. Having said that, I hate plumbing like I hate child abuse.
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  125. Hibernian says:
    @ThreeCranes
    The design was an I beam, which is not near as stable as a box section. Most bridges utilize a box somewhere in their design. In the case of a steel truss bridge, you drive right through the middle of it. In a suspension bridge, you're generally driving on a box.

    I CAD drafted (copied only) the United States Department of Transportation approved concrete bridge section plan that is used on most of the secondary roads at the county and city level in America. There's a lot of rebar in that structure, both longitudinally and transversally, vertically holding the top and bottom together. The rebar is so thick that there is no place where, if the bridge were broken open, you would see chunks of unreinforced concrete, as you see in the pictures of the fallen pedestrian bridge in Miami. All that unreinforced concrete is just dead weight.

    And as you point out--correctly--there's just no way that properly cured concrete would pulverize in the way the Miami bridge did. Just look at pictures of collapsed Cypress St. Viaduct in Oakland from the 1989 La Prieta earthquake.

    https://upload.wikimedia.org/wikipedia/commons/9/91/Cypress_collapsed.jpg

    Lotsa rebar there too.

    But as I've pointed out before, living here in Florida I see contractors pour concrete all the time and just walk away. No attempt to keep it wet for a minimum of 7 days. Concrete cures by hydration, not by drying out. Drying out stops the curing process which is a hyperbola type curve, with nearly full strength in 28 days and most of the gains achieved in 7, a practical compromise. It may well be too that the ambient temperature was too hot for a proper cure.

    “All that unreinforced concrete is just dead weight.”

    Unreninforced or lightly reinforced concrete above the neutral axis provides compressive strength where it is needed.

    I agree with your last paragraph. Contractors are very negligent about pouring concrete and ensuring that it cures properly.

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  126. JMcG says:
    @Twodees Partain
    The engineers involved in the process, the E/M designer, their supervision/oversight engineers, the inspecting engineers on the architect's team, and everyone else who was involved in getting the design approved and put into production allowed the mistake to pass and it took a journeyman electrician (me) to start the process of getting a design change on-site started to correct the mistake.

    About plumbers and electricians, it has always been a wonder to me how DIY homeowners are more willing to attempt electrical repairs than plumbing repairs. If they make a mistake in their plumbing, they'll get water damage and/or a mess to clean up. If they make a mistake with their electrical system, they could get a house fire (as you mentioned) or someone may be killed by electrocution.

    Blame the DYI books and YouTube. It is appalling what people will attempt to do with electricity in their homes. Having said that, I hate plumbing like I hate child abuse.

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    • Replies: @Twodees Partain
    Yes, that's true. That willingness to tamper with the home electrical system also predates youtube by generations.
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  127. @Jim Don Bob

    So does O’Rourke, come to think of it.
     
    He said he voted for HRC, so f**k him.

    He said he voted for HRC, so f**k him.

    Agree.

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    • Replies: @Bubba
    I second that "Agree."
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  128. Bubba says:
    @Charles Erwin Wilson II

    He said he voted for HRC, so f**k him.
     
    Agree.

    I second that “Agree.”

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  129. @JMcG
    Blame the DYI books and YouTube. It is appalling what people will attempt to do with electricity in their homes. Having said that, I hate plumbing like I hate child abuse.

    Yes, that’s true. That willingness to tamper with the home electrical system also predates youtube by generations.

    Read More
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