Posted on 03/15/2018 3:29:54 PM PDT by Kaslin
UPDATE: Thanks to our friends at Twitchy, there are some people who think this horrific bridge collapse is Trump’s fault—and that he should be impeached for it
Brand new unopened Pedestrian Bridge collapses in Miami. The era of Trump is turning America into a corrupt 3rd World country. Florida needs to be run by Democrats, the Republicans just make up their own versions of reality. #TheResistance pic.twitter.com/Cd0V0800cE— james johnson (@jimmyhawk9) March 15, 2018
Horrible tragedy in Florida. Bridge collapse. I don't know what regulations were followed or not followed. Way to early to say what happened here.
I can say that Trump has gone out of his way to loosen building regulations. He has openly bragged about it.— Carol Baker (@Carol_Baker73) March 15, 2018
Trump gets rid of regulations on building things and a bridge collapsed thanks Trump Impeach him now— Roger bomkamp (@bomkamp_roger) March 15, 2018
***
Several people are reported dead after a 950-ton pedestrian bridge at Florida International University in Miami. (via CBS Miami):
Florida International University’s (FIU) massive new pedestrian bridge collapsed Thursday afternoon killing several people.
The 950-ton bridge, located at 109th Ave and 8th Street, collapsed on a number of cars.
Florida Highway Patrol confirms several people are dead due to the collapse. They also said several cars have been crushed.
At least one person was taken as a trauma alert to the hospital, according to Miami-Dade Fire Rescue.
#FIUalert: The pedestrian bridge across Southwest Eighth Street has collapsed, please avoid the area.— FIU (@FIU) March 15, 2018
Police telling me there are “mass casualties” after bridge at FIU collapses to the ground. @MiamiHerald— Monique O. Madan (@MoniqueOMadan) March 15, 2018
In a statement, FIU said,“We are shocked and saddened about the tragic events unfolding at the FIU-Sweetwater pedestrian bridge. At this time we are still involved in the rescue efforts and gathering information. We are working closely with authorities and first responders on the scene. We will share updates as we have them.”
Gov. Rick Scott has been in contact with Miami-Dade County Police Chief Juan Perez. He is also en route to FIU to be briefed by law enforcement and university officials.
I’m on my way to Florida International University to be briefed by local law enforcement and university officials. pic.twitter.com/4RyoeELh9m— Rick Scott (@FLGovScott) March 15, 2018
Terrible news coming from Miami as a pedestrian bridge has collapsed at @FIU and multiple deaths are reported. We will pray for the victims and the entire Panther community.— Marco Rubio (@marcorubio) March 15, 2018
I have spoken with Miami-Dade County Police Chief Juan Perez about the pedestrian bridge collapse at FIU. I will be in constant communication with law enforcement throughout the day.— Rick Scott (@FLGovScott) March 15, 2018
FIU President Mark B. Rosenberg had praised the completion of the bridge in a now-deleted tweet on March 13 saying, “FIU is about building bridges and student safety. This project accomplishes our mission beautifully.” Structural monitoring was conducted on March 12.
Huh. Wonder why this Tweet just disappeared a minute ago. @wupton pic.twitter.com/8zH8omceGp— Gabriel S. Sanchez (@OpusPublicum) March 15, 2018
Wow. pic.twitter.com/M6ErMHJSxh— William J. Upton (@wupton) March 15, 2018
#BREAKING: The FIU pedestrian bridge recently put in place has collapsed on SW 8th St pic.twitter.com/BZfQu2c5bh— Joel Franco (@OfficialJoelF) March 15, 2018
We’ll keep you updated.
Ban pedestrian bridges! Have a school walkout!
I would assume the structural modeling of the deck and its truss was done assuming that the cables were in place. Without them the loading patterns would be completely different.
The whole thing seems crazy.
Nor do they shoot innocent people.
As a structural drafter for over 30 years, I have worked with a whole LOT of engineers and a bunch of architects too... of the two, as a group, it is NOT the engineers that are arrogant.
I saw a video of the collapse. It did not show anything preceding it.
I thought I could give some people some information most wont know, the long explanation of what post tension is, for anybody interested.
I read this and suspect somebody missed something in the communication process, I would think any stress test occurred the minute they raised the bridge... I think they meant re-stressing the cables.
Post tension is a design where they run cables though the form work instead of mild steel reinforcing people are used to in concrete construction, also known a rebar.
Post tension strands are a stainless steel cable. The ones we specified were 1/2” diameter. These cables are in a plastic sleeve so when concrete is poured they are not touching the concrete.
MANY post tension failures years after are because the concrete came into contact with the stainless steel and a reaction starts that eventually will degrade the cable enough it will break. There is an admixture used in normal concrete at times that is specifically excluded when doing post tension, been SO long I cant remember what that is now.
The bridges I have done post tensioned, have had groups of these cables all ran together, the one I remember had 6 cables together in each run.
After the concrete is poured, and cures to a certain strength which we know it reached, because we take test cylinders when concrete is poured and then a testing company breaks these cylinders at different points in time and and determines the strength and when cables can be stressed so at that point per design, the concrete should be strong enough to stress the cables. One home builder had it’s concrete guys spending a few extra bucks getting higher strength concrete so that it reached the strength they needed to stress it sooner. That got framing crews in ahead of schedule and was how they were cranking these out so fast back in the boom.
Stressing the cables, they take this pulling machine, made up with hydraulics and it clamps on to the cable and starts pulling. As it is pulling, there is a wedge in there so the cable cant relax. Its been a few years but it seemed like they were stressing these 1/2 inch cables to about 30,000 pounds of tension on them. As an inspector, I did not care the actual load, we had a chart and knew how long that cable would stretch when it was properly tensioned... I went and measured how much it had moved (they painted the end before stressing so you had a physical mark to measure too.
I could be wrong, I just dont see them “stress” testing it over lanes of moving traffic when they could have lifted it where they built it to test it... the lift itself should have been the test I would think.
I had heard the engineer noticed some cables were not tight enough and they were re-stressing them. I suppose the lift could have de-stressed them, but I am NOT an engineer and I don’t know how that could have happened.
I have drawn a few bridges, and a couple were post-tensioned, but Most of my post-tension experience was in residential construction, for houses or apartment buildings, we did a post tension foundation and the slabs had these same cables laid out about 3’ on center each way. It cost a little more, I heard at one time an extra $500 per house, to build but long term saved them money, builders did not have people coming back with little cracks in sheet rock because one area settled a little bit they wanted fixed a few years later.
For a house, they paid us to be present for 3 inspections plus cylinders. We had a pre-pour inspection, one while they were pouring to take samples and make cylinders for one of 4 of these sort of random to keep them honest, not knowing if we were coming or not... One after they stressed cables to check elongations and a final one after they cut the cables off and patched the little grout plug that sealed up the end where they stressed it.
“of the two, as a group, it is NOT the engineers that are arrogant.”
The engineers I have know were so damned smart that they couldn’t help looking arrogant to a certain type of person.
Some people call another arrogant when they really mean,”Standing next to you I can see how stupid I am.”
Point well made!
We just saw it, too. Nothing was dropped. It collapsed FAST!
What steel? Look at the remains the pieces of the span. No cohesion, no steel.
https://canadafreepress.com/article/father-of-collapsed-florida-bridge-was-obama-champion-of-change-in-2015
http://freerepublic.com/focus/f-news/3640266/posts
Or you can read it directly from his site
Wow, I was in Mexico once and they were building a 2-story building of concrete and they were using cardboard for reinforcement. Why no steel?
I fully understand the weaknesses in the inspection process, most of it is political and the weak links are the contractor building team attitudes concerning quality vs schedule and the due diligence/experience and talents of the Structural Engineers.
No, you didn’t come off as pretentious at all. You sounded like you have knowledge about the subject that most people do not have, and I was curious. And thank you for sharing your experience. I am so used to the medical research world that it is fascinating to run across someone whose expertise is in a completely different area.
That is an excellent observation. I’ve run across that phenomenon, usually when people who “studied” at Google university are involved.
Great points.
The bridge may have been well designed, but the construction implementation of that design might be as challenging and more complex than the design itself.
So many “which comes first? The chicken or the egg?” scenarios.
I was surprised to see the span being rotated into place prior to the center post being erected.
Additionally, if temporary supports were being installed beneath and mid-span, it really changes the structural calcs mid construction.
It’s very easy for mid level managers to issue edicts such as no cost escalation, no schedule creep, simply so they don’t face problems to manage. Underlings respond and frequently the engineering wherewithal is absent when the construction folk take charge. Even with IBC mandated structural inspections during construction, many construction foremen and QC managers aren’t even cognizant of code changes from 12 years ago.
Good news is the School of Architecture had their students watch the bridge placement, since it was state of the art, rapid construction. Lots of lessons to be learned.
Prayers out for the families of the injured and killed.
Have a school walkout over a newly-installed, faulty, inferior, experimental pedestrian bridge! /sarc
Thank you...very interesting. Only fraud and graft would have allowed this faulty structure to be swung into place, with utter disregard for human lives.
I understand how critical certain inspections are, but I have always used those regulations as an example of HOW the government actually creates jobs. I cant tell you how many hours I stood there and watched them pump grout in a block wall and make sure they vibrated every cell. Not complaining, Much preferable to sitting at my desk! Just saying that is how it IS DONE, when people tell you Government DOES NOT create jobs. I was inspecting schools, so in that case, yes, build it into the contract and put me there every time, I am just talking in general.
There is something to be said for keeping them honest and yes we are all human and can make mistakes too, but random inspections would suffice. Once the rebar is coming out of the ground, they usually don’t miss it up the wall and not really a need other than checking some lintels or embeds after that. If they don’t build it right, it will fail and they will be out of a job and possibly in legal trouble too. Code now says ALL masonry must be inspected... now that means even a trash enclosure wall if they go by letter of law.
To simplify, my house was built before 1970 and does not have a stick of reinforcing anywhere in the block walls, been standing for 60 years now, if built today it would have to have reinforcing (which yes I would prefer some anyway, at least corners and a bond beam at top) and ALSO be inspected while it was being grouted. My time was billed at $100/hr including travel time getting there and back and that was 10+ years ago.
Especially when the contract is construction costs plus 10%. I always thought that was the way to go, because it eliminated the benefit of cutting corners by using cheaper materials or leaving out some reinforcing or whatever. Similar to the government budget process, the more you spend the more you make (or in gov. case get to spend next year)
You are most correct from what I have seen, Scheduling dictates the need of cutting corners much of the time today if not to just make things easier for them, like the concrete guys wanting more water so it “flows” better, they know cant go too far or it wont finish right, but ANY over the mix design weakens it and will cause more cracking in the finished product.
I started drawing structural plans by hand, even still a couple bridges back then and the computer generation was a nightmare for our industry. We lost any time to do the jobs... Everybody thought we just pushed a button and it was magically done now. It was always a feast or famine industry and we lost all scheduling time, everything is fast tracked and that causes errors.
Interesting Intel Fab (IV or V cant remember) was one of the first thing I drew details for. Look up Fillmore center in San Francisco, it was biggest project I was ever involved in, about 5 years in, still young in my career, but taught me about concrete structures. We had 3 different national offices of our same A & E firm all working on different phases of it... a bunch of towers and other shorter buildings connected with a plaza level that was a whole block each way. Then the earthquake hit and the other two offices areas did not perform quite as well as what we had done... They transferred engineers from our office to go help tighten things up in the other two after we spent a few months doing repairs to fix cracks. I did my only set of wall elevations showing cracks and where to epoxy inject...
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