Investigators Find Design Flaw As Cause Of Minnesota Bridge Collapse

AP:

Federal investigators have identified a design flaw as the cause of last year's Interstate 35W Minneapolis bridge collapse that killed 13 people and injured about 100, a congressional official said Tuesday.

The official, who was briefed by the National Transportation Safety Board, said that investigators found a design flaw in the bridge's gusset plates, which are the steel plates that tie steel beams together. The official spoke on the condition of anonymity so as not to pre-empt an update being provided later Tuesday by the NTSB chairman, Mark V. Rosenker.

Read the whole story: AP

Comments

[MIKEBC]

I WONDER HOW MANY OTHER BRIDGES IN THE USA ALSO HAVE 1/2 INCH THICK GUSSET PLATES?

[TakeSake]

"The official, who was briefed by the National Transportation Safety Board, said that investigators found a design flaw in the bridge's gusset plates, which are the steel plates that tie steel beams together."

This is specious. It is merely that the gusset was the first part to fail. If the gussets were thicker there would have been something else, and so on until the entire bridge was a solid block of cast iron.

A design flaw would make the bridge collapse in 4 days or 4 weeks, not 40 years.

No, the real cause is lack of maintenance. This is somethings that is actually impossible to keep up with for that kind of structure because of how Minnesota deals with winter.

Cars can rust out in 10 years due to road salt. Bridges are made of steel, and are subjected to extra generous doses. Corrosion due to this is the real reason the bridge became weak enough to collapse. Holes and edges serve as initiation points for the corrosion, and he gusset plates are naturally filled with them.

[ohiomark]

Oh no!!! You mean it wasn't Bush's fault?

I thought EVERYTHING was Bush's fault.

[bitabingbitabangbitaboom]

The local Iron Workers Union and its members knew that the gussets where overloaded back in 1967.

But nobodies with the college degrees on that building site wanted to know what the fuck some overpaid blue collar steel workers had to say or thought about it.

The are a whole bunch of retired welders and riggers coming on 70 years old say "I told you so."

[hoodie]

What killed that bridge was a country too consumed with shopping at Walmart (and giving them huge tax breaks), guzzling fossil fuel in the SUV's and giving tax breaks to the wealthiest pukes around. It is not sexy to invest in roads, bridges, schools or poor people. We have got to get out of this mindset and give up all our gadgets and junk. A good old depression followed by some new social programs sound pretty good right now.

[nanotubz]

The issues of US bridges, dams and levees dates back into the Carter administration. Administrations have proposed, by Congress has been ill disposed.

[lavndrblue]

So, Huffingtonpost becomes the mouthpiece for Minnesota Governor Tim Pawlenty (R) just as Fox News is the mouthpiece for the Bush Administration. By parsing out only one of the reasons for the collapse in the NTSB report we absolve Tim Pawlenty and his administration's negligence of our infrastructure.

[SupremeIdiot]

"When they added the weight they didn't realize they were bringing the margins of safety down to where they didn't exist anymore," he said.
_______________________________________________

That would be a lie.

Even a firefighter like me knows enough about structural engineering to know that when something is designed for a certain weight that anytime you add more weight to it you are decreasing the margin for error.

We learn this in the academy. To a true structural engineer it should be gospel.

[blahber]

amzing how you dingbats find a way to bring bush up while talking about bridges collpasing. don't kid yourselves, actually, i'm quite certain you aren't kidding yourselves, only delusional about kidding others ...

too, too funny

[DatelessNerd]

In many ways, this situation is like the 1986 Challenger explosion. The problem wasn't money. Instead, it was the process.

NASA could afford better "O" rings, and Minnesota could afford thicker gussets. But just as NASA insisted on flying the shuttle in cold temperatures, Minnesota added additional weight (pavement, lane dividers, etc.) to the 35W bridge without confirming it could safely support the additional load.

That being said, America's infrastructure is a disaster waiting to happen. It's far sexier for legislators to support new projects than to allocate tax money to maintain what's already there. Upkeep needs to come first, before we build new structures that we can't afford to maintain.

And yes, redeploying our troops would save tons of money that could be used to rebuild THIS country and create jobs that can't be outsourced!

[MysticInd]

I am calling you out on your erroreous heading. At no time, did the NTSB investigator say these gussetts were the single cause of the collapse. They said they found there was a design flaw for weight baring. And cautioned all reporters that this was not the final determination of the collapse of the bridge.

You could say you are in great company as I heard the wrong reporting on NBC nightly News tonight as well.

What can't people understand English anymore... Or do you just delight to make stuff up.

[atlantajoe]

tililek, money had nothing to do with it. The job of maintaining bridges is up to the state. They have a large cash surplus so maintanance was not important to the MN politicians. In fact, Several MN lawmakers had earmarks in the budget and none for bridge maintanence. learn the role of gov't, feds build bridges on interstate and states mantain them. Debate that! I will respond with more debate when you show what the military budget has to do with MN bridge inspections.

[OhgReaTone]

This country has old bridges - some of them must have been designed well. I recently crossed the Amelia Earhart bridge over the Missouri River. I think it was built in 1937. Crossing the bridge with big trucks all around was an emotional experience.
Ohg
http://thefiresidepost.com/2007/12/23/crossing-the-amelia-earhart-bridge/

[americanfabius]

Leave it to you people to immediately assume conspiracy and coverup when a design flaw is found and underfunding by the government is not the reason for this tragedy.

[DRaymond]

I remember my structural engineering instructor in college saying of course to size the elements correctly but once you've done that pay attention to the connectors, because the connectors are where your problems are going to occur.

Also while they are saying that the gussets were too thin it is equally important that the subsequent renovations added significantly to the weight carried by the bridge.

I am also inclined to agree with the conclusion that the construction materials were the final straw. It isn't that they were heavier than the traffic that the bridge would have carried when operating but that they were piled in one place, which changes the distribution of stresses in a truss.