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Horrific pedestrian bridge collapse at Florida International U. kills 4

Horrific pedestrian bridge collapse at Florida International U. kills 4

Reports indicate bridge was undergoing “stress test” at time of accident.

https://www.youtube.com/watch?v=IPthP3MXcs8

Florida International University was the center of a horrific tragedy this Thursday as a pedestrian bridge under construction collapsed onto the road below, killing four and injuring many more.

Aerial footage showed first responders tending to victims at the scene, searching for people in the rubble and loading others on stretchers into ambulances.

Firefighters have pulled out at least four deceased people from the rubble, Miami-Dade Fire Chief Dave Downey said at a Thursday evening press conference.

The collapse occurred at about 1:30 p.m., Miami-Dade Fire Rescue Division Chief Paul Estopinan said in a press conference Thursday afternoon.

As of 5 p.m., a minimum of eight vehicles were trapped under the rubble, Estopinan said. Some workers were on the bridge when it collapsed, but officials did not detail whether any of them were among the dead.

In addition to the dead, a number of people were severely injured.

Dr. Mark McKenney says at a news conference Thursday that two of the people Kendall Regional Medical Center received were in “extremely critical” condition. He says the other eight were stable, with injuries such as “bruises and abrasions to broken bones.”

Of the two more serious cases, McKenney said one arrived at the hospital in cardiac arrest but was revived, and the other has a serious brain injury.

The National Transportation Safety Board is sending a team to investigate the collapse to determine the cause. While there is no known cause at the present time, some troubling information has been revealed in news reports.

For example, the bridge was undergoing a stress test at the same time the 7-lane road underneath was open to traffic.

…Any such test, experts told the Miami Herald, requires extreme care and precision to avoid overwhelming the structure. Too much weight on the bridge or over-tightened cables could cause problems.

The firms behind the project are Miami-based MCM and Figg Bridge Group, a well-known Tallahassee design company. Miami-Dade Mayor Carlos Gimenez said that crews were conducting a stress test on the bridge Thursday, and Miami-Dade Fire Rescue confirmed two workers were on the bridge when it collapsed.

Furthermore, the two of the firms involved in the bridge construction [Munilla Construction Management (MCM) and the FIGG Bridge Group] have had a recent history of significant safety complaints.

… 10 days ago, the company [MCM] was sued in South Florida by a TSA employee who was hurt at the Fort Lauderdale airport. The employee’s lawyer alleges that a makeshift bridge MCM built for workers to use while the company does construction at the airport broke under his weight.

As for FIGG, a 90-ton portion of a bridge the company was assembling in Virginia in June 2012 fell apart while under construction. The Virginian Pilot reports four workers were hurt and that state regulators fined FIGG $28,000 for safety violations saying it was “pure luck no one was killed.”

The project included a 174-foot, 950-ton section that was built adjacent to Southwest Eight Street using Accelerated Bridge Construction (ABC) methods. According to the university, the bridge was slated to open in 2019 to foot traffic and was touted to be historic in many ways:

  • It was designed to withstand a Category 5 hurricane.
  • Its durability was supposed to exceed 100 years.
  • It’s the first bridge in the world to be constructed entirely of self-cleaning concrete: It’s made of titanium dioxide which, when exposed to sunlight, captures pollutant particles from the air and cleans its own concrete surfaces.
  • It was installed in just a few hours just five days ago, although its construction wasn’t finished.
  • The main span was built nearby to avoid traffic interruption and moved using a state-of-the-art, computer-controlled system that carried and set the 950-ton section. It’s called Self-Propelled Modular Transportation and this was the largest pedestrian bridge in US history to be moved using this method.

Sadly, the FIU pedestrian bridge has made history. Hopefully, the root causes of the collapse can be clearly determined so this incident will not be repeated.

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Comments

Guessing it didn’t pass.

From the construction company’s web site you can see an artist’s conception of how the completed bridge will look like. The photos of the wreckage show that there is no tower and so no suspension cables helping support the long I-beam-type concrete construction. If the concrete was poured recently and not allowed to cure properly it could be substantially weaker than planned and this could have contributed to the early bridge failure.
http://www.mcm-us.com/projects/road-bridges/road-and-bridges-fiu-pedestrian-bridge

In addition the Washington Post has more information and pictures on the I-beam type construction planned to be supported by suspension cables running to an unbuilt tower: https://www.washingtonpost.com/news/grade-point/wp/2018/03/15/new-pedestrian-bridge-collapses-at-florida-international-university-injuring-several/?utm_term=.c9d1cb43abd7

If they were conducting stress tests, somebody needs to go to jail for criminal negligence.

Hubris or negligence? I would say both.

Stress testing with active traffic passing under bridge. Usually such blunders occur at night. This is reminiscent of Minnesota bridge disaster with overloaded bridge during renovation. With no apparent curve of bridge design the degree of compressive forces required for structural integrity must be very great. Just not great enough in this case.

G. de La Hoya | March 16, 2018 at 7:59 am

Reuters stated that the funding for this bridge was from the TIGER grants which were started in 2009, signed into law by Obama. Of course, ‘Obama didn’t build that’ 🙂

That bridge was supposed to be supported from above by cables like the Sunshine Skyway bridge in Tampa. Those weren’t in place yet, so I don’t see how the bridge could even support its own weight without them.

Perhaps something to remember as we’re told how great driverless cars will be.

    Paul in reply to geoih. | March 16, 2018 at 9:14 am

    I have no doubt that driverless cars will kill people. And I also have no doubt that they’ll kill FAR fewer people than human drivers do. Plus I’ll be able to drink a gin and tonic while riding in my car.

      Exiliado in reply to Paul. | March 16, 2018 at 9:32 am

      Don’t hope too much for that gin and tonic. That will most likely remain illegal to do, driverless cars or not.

    Petrushka in reply to geoih. | March 16, 2018 at 9:30 am

    Current cars with automatic braking have half the accidents of cars without. We will, of course, remember the ones caused by malfunction.

Unlike a lab experiment, a test of any kind of such a structure that is place should not determine its limit, but it should confirm that it meets the test criteria that is within non-destructive limits(many tests can cause invisible and permanent harm).

For this to occur, there has to be gross negligence, gross incompetence, or both. This includes the design, materials, and construction. My guess is there were marginal deficiencies on all three dimensions with the thinking that one could “get away” with a shortcut. If shortcuts overlap, things go wrong. People need to go to jail for this.

Snopercod is right. It looks to me like the builders removed the temporary bridge supports before adding the tower and supporting cables shown in the sketch in this link:

https://www.cbsnews.com/news/florida-international-university-pedestrian-bridge-collapse-sweetwater-construction-today-2018-03-15/

Or maybe that part of the design was eliminated.  Either way, it looks like an obvious and horrendous blunder.

All right, the armchair judges and juries can stand down. We will never be given enough information to guess at who and what screwed up.

We rely on reporting from media reporters and that is typically full of misinformation and speculation in the very short term. Issues to examine 1)was the design adequate 2)if so, was the fabrication done properly (proper curing of properly reinforced concrete of verified strength) 3) was the procedure to lift the walkway in place acceptable 4) why would anyone stress test an incomplete structure – the walkway was meant to have a center pillar and suspension tendons above the walkway roof 5) for that matter, if the walkway was safe as placed, what is the purpose of the center pillar and suspension tendons
I’ve frequently crossed the Sunshine Bridge near Tampa carrying I-275 to St Petes and and Tampa. Same type of suspension. I have also been on a similar bridge on I-93 through the center of Boston. Nice looking and durable (so far).
I’m not ready to hang anyone until these questions are answered (and probably a lot more). You can’t rely on “if it bleeds it leads” local reporting.
Also, for 25 years I have commuted over the Jamestown-Verrazzanno Bridge over Narragansett Bay. That bridge is made of precast box girders barged from a few miles away and hoisted into place between foundation piers with joints cast in place and post tensioned. It did need repairs about 10 years ago and is currently rated fair. It will need more work, like way too many infrastructure items nationwide.
Seems to me that the design concept (single pillar and tendon suspension) and the offsite fabrication both are nothing radical. Somebody did something wrong or risky and NTSB will find the cause or causes. They are thorough and will take some time, just as when they investigate plane crashes.

This bridge was a new design and as such should have been stress tested using a model and it should have been tested to failure. In aviation, all new designs are tested to a percentage above the design limits to be sure that if an unexpected event occurs the plane will survive. I do not know the details of this horrible accident but it looks like testing was being done before all elements were in place. Why and how this was done will probably end up in court.

Bottom line: something went wrong here. And, it probably going to require a significant period of investigation to determine exactly what went wrong. Then we will see the lawsuits filed. And, depending on what is ultimately discerned to be the cause of the failure, the appropriate entities will be named in the suits.

For the rest of us, this is an abject lesson in not driving under structures which are currently under construction.

“It was designed to withstand a Category 5 hurricane.
Its durability was supposed to exceed 100 years.
It’s the first bridge in the world to be constructed entirely of self-cleaning concrete: It’s made of titanium dioxide which, when exposed to sunlight, captures pollutant particles from the air and cleans its own concrete surfaces.
It was installed in just a few hours just five days ago, although its construction wasn’t finished.
The main span was built nearby to avoid traffic interruption and moved using a state-of-the-art, computer-controlled system that carried and set the 950-ton section. It’s called Self-Propelled Modular Transportation and this was the largest pedestrian bridge in US history to be moved using this method.”

These grandiose proclamations are eerily reminiscent of the Titanic. Hubris probably led to the idea that a new prototype bridge can certainly be stress tested while traffic is green because the bridge is indestructible.

    floridaman in reply to healthguyfsu. | March 16, 2018 at 2:07 pm

    Did that qualifier get past you? “this was the largest pedestrian bridge in US history to be moved using this method.” Railroad and highway bridges are built all over the world using this method. Nothing unusual at all.

A failure like this would be analyzed in a 2×3 matrix:
a) Negligence vs incompetence.
b) design, materials, or construction.

The root cause can be one or more of the six boxes. Gravity, forces, statics, dynamics, etc. are all well understood. I think the only question will be whether the root cause will be covered up or will be out in the open.

buckeyeminuteman | March 16, 2018 at 1:19 pm

Hastily created “shovel-ready jobs”

The other thing to remember- it was only half a bridge. The pillar by the river was the center pillar. I’m still wondering how the other section of bridge was going to be placed. The method used for the first section couldn’t be used.

In OKC, they are working on a section of I-235 where the railroad bridge needed to be redone. The new span was built on site and then they closed the road for a weekend to move it. They will close the road for another weekend to tear down the old bridge. It will be interesting to see if the local news compares this activity to the one in FL.

http://newsok.com/interstate-235-will-be-closed-in-both-directions-friday-night-for-three-days-to-move-railroad-bridges/article/5580932

I haven’t been down that road yet since it is still a mess. I’ll wait a few more months (or years) until the entire stretch is finished.

Sometimes the builder makes some insignificant modification that the designer didn’t test or anticipate.

The poster child for that is another pedestrian bridge that failed. The Hyatt Regency walkway collapse.

    randian in reply to Petrushka. | March 16, 2018 at 11:00 pm

    If it can lead to collapse it’s hardly insignificant. Builders shouldn’t make any modifications, other than purely cosmetic ones, without consulting with the designer.

“The Virginian Pilot reports four workers were hurt and that state regulators fined FIGG $28,000 for safety violations saying it was “pure luck no one was killed.””

This means nothing. After any construction accident, investigators are all over the place playing CYA so no one asked where they were before the accident. A $28,000.00 fine could be from a couple of guys wearing out of date fall arrest gear and would have nothing to do the actual accident.

The stress tests were on the anchor points where the cables would connect, but there were no cables yet. I’ve read that the crane cable snapped during the test and the recoil brought the bridge down. This is completely avoidable and inexcusable in that the stress test could have been done before installing the bridge. I’m guessing that the council gave the builders a time window to install the bridge in situ and the builders took it, figuring that they could finish the stress testing after the installation. Combination of bureaucracy and hubris.

Here is an example of a bridge that did not collapse when a cable snapped.

https://www.youtube.com/watch?v=rfBlO-5ZUmw

Scots are famous as engineers.

It is madness to be stress testing a new bridge with a new construction method with live traffic under it when the designed supports were not in place and the temporary supports had been removed or were not adequately designed or were improperly built. Ultimately, this was a human failure. It will all come out (at least the physical stuff) in the investigations that will be forthcoming. This is not rocket science.

Chicago has dozens of bridges over one hundred years old, including drawbridges, still carrying heavy traffic.

https://max34ron.wordpress.com/2016/03/24/how-many-100-year-old-bridges-are-there-in-chicago/

One suspects that had the Florida bridge been build a century ago, it would still be standing, ugly, perhaps, but standing and useful.

More bridge history:

The 12-foot wide Wright State Way pedestrian bridge, which cost $3.5 million to build, spans 467 feet and connects the Wright Stake University campus and Fairborn to the city of Beavercreek, crossing over I-675. It was built in 2015 and is in good condition.

The bridge that collapsed in Florida spanned 170 feet (for a short time) and was being built at a cost of $14.2 million. 

What does WSU and Ohio know that FIU and Florida do not?

http://www.whio.com/news/florida-bridge-design-differed-from-wright-state-way-over-675/LLmezPki3d6kGgA16qZKrJ/amp.html

    bobtuba in reply to Cache. | March 16, 2018 at 5:11 pm

    I’m sure the Wright State bridge was insufficiently green / eco / renewable / your fav buzzword here. Moreover, the Ohio engineering team was also not appropriately diverse and woke. And they used math. And stuff.
    On a serious note, this was a pedestrian bridge. And that span weighed 950 freaking tons? Are you kidding me? Just use steel and you can do it for a small fraction of that weight.

The new design was also noted for reduced traffic disruption. Does that mean the debris is easier to remove?

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