Minneapolis 35W bridge collapse

[thebaldguy]

We just had a massive bridge collapse here in Minneapolis. This is one of the main arteries in the city; I think something like 150,000+ cars go over this bridge daily. Driving home, we could see the smoke. We biked down there, and the scene is unreal. This bridge dropped 75+ feet down into the river.

I shudder to think about how many cars were on that bridge at 6:05 PM rush hour/pre Twins game. However, there were only two lanes open for traffic each way during current construction.

[mountainclmbr]

http://www.nace.org/nace/content/publicaffairs/media/bridge.asp

The U.S. Federal Highway Administration (FHWA) has rated almost 200,000 bridges, or one of every three bridges in the U.S., as structurally deficient or functionally obsolete. Furthermore, more than one-fourth of all bridges are over 50 years old, the average design-life of a bridge. The Strategic Highway Research Program (SHRP) of the U.S. National Research Council recently estimated that the cost of damage to America's bridges currently stands at about $20 billion and is increasing at the rate of $500 million per year. SHRP concluded that the structural deterioration found in these bridges is primarily the result of corrosion.

What is Corrosion and How Do We Control It?

Corrosion is the deterioration of a material, usually a metal that results from a reaction with its environment. Over a period of time the components of a bridge may deteriorate to the extent that the bridge is no longer safe. However, using current corrosion control technology in conjunction with maintenance and monitoring guidelines, we are preventing their decay and extending the lifespan of bridges to a certain extent, but with multiple corrosion protection system strategies, the lifespan can be extended by decades.

Common strategies for corrosion control include:

(1) designing the structure with corrosion prevention in mind and selecting corrosion-resistant materials when constructing and refurbishing bridges;

(2) the application of protective coatings, membranes, and protective sealers to the bridge which can serve as a barriers to corrosive environments;

(3) the use of direct electrical current and sacrificial materials to mitigate corrosion on reinforced concrete and bridge decks, a process known as "cathodic protection" and

(4) electrochemical chloride extraction.

Why are Bridges Deteriorating?

A number of factors contribute to bridge corrosion. One of the most common is the use of deicing salts on roads and bridges, a practice which has contributed significantly to the deterioration of such structures. The salts cause corrosion of the steel reinforcing bars and other steel components supporting the bridge. This form of corrosion is the main cause of concrete bridge deterioration. Other problems that lead to corrosion include bridge designs that do not adequately consider drainage requirements, stresses, shrinkage, or expansion, and environmental factors such as frequent freezing and thawing cycles.

Compounding the effects of a corrosive environment is the lack of proper monitoring and maintenance of bridges. Technology exists that can keep bridges free from the harmful effects of corrosion, but it is only effective if it is used properly and regularly monitored.

[Manedwolf]

And I'd just seen a thing about how the US infrastructure, mostly built in the "expansion" age of the 1950's, the era of public works...is falling apart, with bridges, dams, power infrastructure and all that's being used 20 years past its design lifetime...

[thebaldguy]

This is Minnesota; we salt our roads to the max. Cars here rust out even if you wash them top and bottom. This bridge was famous for years as a black ice hazard in extremely cold (-10 F and colder) weather because of the river and car exhaust. They salted the bridge all the time. I had a close call one night years ago trying to avoid an accident; I avoided all mangled cars, did a 360, and gently came to a rest against the guardrail. That took a few years off of my life. Since then, they have installed liquid de-icers in the pavement like underground sprinklers in your lawn.

[roo_ster]

Maybe they ought to use the fuel taxes collected on, you know, the ROAD and BRIDGES rather than mass-tran foolishness.  It would also be nice to see fewer corn/eth subsidies and more spend on infrastructure.

[mountainclmbr]

The plastic I saw from the edges of the broken sections must have been put under the pavement to prevent the deicing fluid from corroding the metal under the pavement. I bet the spray got on any exposed surface though.

Seems the leftists over at Daily Kos are blaming Bush:

http://www.americanthinker.com/blog/2007/08/leftist_dementia_blaming_bush.html

We spend billions in Iraq


While we fall apart at home.



We have been warned


by engineers that our nation's infrastructure is in dire need of repair and upgrade.


Who needs terrorism when the inept GOP runs our nation into the ground. The "terrorists" can just sit back and watch as our nation falls apart.


Mission Accomplished.



No one has the balls to take this on


Every week there's a new national tragedy...tainted food, nutcases with automatic weapons, structural damage to cities, hospital patients dropped on the streets, dysfuctional transportation system, poorly cared for vets, trashed education system, national disasters from global warming.  I am waiting for a national figure with the balls to call these warning signs what they are: Republican disdain for and neglect of government oversight,venality, insensitivity to human suffering,  tax breaks for rich folks, blatant government incompetence, dirty politics, and bleeding our resources in an immoral f-----k war.




you want services, you have to PAY FOR THEM.


That includes roads, electric grid, public transportation, airports, air traffic control, police, firemen, schools, colleges, and last AND least, military.


NO corporation is going to do those things. THERE'S NO PROFIT IN IT. And there SHOULDN'T be.


You can't run a 21st century country with a 19th century infrastructure. Or tax structure. Or 19th century thinking.


Scratch that - 16th century thinking.



It is a terrorist attack by Republican budget


cutters



I'm watching this now on Olbermann


I can't help thinking that the Bush tax cuts and corruption has contributed to this.  Our country is falling apart, but Bush doesn't care as long as he cronies get to make money.
And from another popular Kos thread about the incident:
More Republican 'Family Values'?


Move along, nothing to see here folks.


Just another case of people paying with their lives, so the rich can keep "their hard earned money".


Just move along.

Some of the Kos messages mentioned the fact that the 2008 Republican National Convention will take place in Minneapolis. "Netroots" activists on the Left feel that linking the bridge collapse with Republicans can score points with voters and perhaps disparage or spoil the lead up to next year's convention.

[Manedwolf]

No, they're blaming Bush AND the Republican governor. 

Yeah, the infrastructure is crumbling. And all the politicians have known about seriously old past-design-life stuff for a long time, through Bush 1 and Clinton's tenure, too.

[mountainclmbr]

When over 50% of the federal budget is spent on entitlement programs (and growing every year), the problems can only get worse.

[Tallpine]

you want services, you have to PAY FOR THEM.


That includes roads, electric grid, public transportation, airports, air traffic control, police, firemen, schools, colleges, and last AND least, military.


NO corporation is going to do those things. THERE'S NO PROFIT IN IT. And there SHOULDN'T be.

Private enterprise is more than willing to do those things, whenever/wherever there is not a goobermint enforced monopoly.  And why should there not be a profit in providing any service that people need/desire

Look at it this way: everybody needs to eat.  So why isn't food production, distribution, and marketing provided by the goverment?  Do you think govt run supermarkets would be better, cheaper, or provide more selection? (hint: I think they tried that already in the old USSR)

If this bridge had been a private toll road, can you imagine the lawsuits over this catastrophe?  (And the incentive to not allow it to happen)

[Bogie]

Have you guys noticed that ANYTHING and EVERYTHING gets blamed on Bush? Even if he's so far removed from it?

One could almost think that somewhere there's a boiler room full of folks who do nothing but brainstorm and post on "what can we blame on him now?"

It's almost like the zumbo thing - one person attacks, and then it's like pirhannas...
 

[MechAg94]

I am not really interested in toll rodes as long as I pay so much in taxes that is supposed to go to infrastructure.  Eliminate those and then we can talk about more toll roads.

[MechAg94]

I thought all those bridges were supposed to get regular inspections.  It would be interesting to see if they were finding stuff that didn't get addressed.

[mountainclmbr]

The federal tax on gasoline is more per gallon than the evil oil companies make in profit. I wonder how many cents on the dollar actually make it into maintenance or improvements to the roadways.

[DJJ]

In defense of this and all bridges, no doubt what they are calling "structurally deficient" is based on a number that all state DOTs, per federal mandate, assign to all their bridges, called the "sufficiency rating". Sufficiency rating is based on several factors, and condition is only one of those. Others include:

- Geometrics (sight distance, shoulder width, approach and departure alignment, adequacy of guardrail)
- Load-carrying capacity relative to when new
- Load-carrying capacity relative to current design standards - this one always kills because design loads keep getting heavier

A low SR doesn't necessarily mean the bridge is weak, or about to collapse. In Albuquerque, we have a bridge about 2 years old whose SR is low enough to be considered "deficient" - but it's because the urban location forced it to have poor geometrics (that's the new Pennsylvania over I-40 for those playing at home).

Here's another trap: once a bridge's SR gets down to a certain level, it qualifies for federal rehab funds. However, once federal rehab money is spent on it, it's ineligible for more, for 10 years.

So, the point of all that is, don't take the news' claims of "deficient" at face value (of course, the fact that it collapsed seems to suggest that something was wrong).

[Hawkmoon]

This bridge was first rated structurally deficient back in 1990 ... and in 2005 it rated 50 on a scale of 100. The state's response? They inspected it annually instead of bi-annually. An article I just read said they have been aware of fatigue cracks for several years ... so they watch them, and "seal" them. I work in a discipline related to structural engineering, and I work with structural engineers. I know that they do not design bridges (or any structures) to have fatigue cracks in them. And I know that an engineering solution for cracks that develop in service is not to cover the cracks with caulk to "seal" them.

This reminds me of the Mianus River bridge collapse in Connecticut back around 1983. That one was late at night so it "only" killed three people, IIRC. The idiot governor of Connecticut was asked at a press conference if any other Connecticut bridges might be unsafe. His response? "This bridge was safe until 3:47 this morning. Then it fell down."

You ... go ... Gov.

The governor of Minnesota has said that he thinks they did "all they could." However, they did NOT repair known cracks, and the bridge was not scheduled for repair/replacement until 2020. Obviously, it wouldn't possibly have lasted that long. And with only four lanes open, it was only carrying part of the design load. The state has some massive responsibility on its shoulders, but I'm sure they'll find a way to double-talk their way out of accepting it.

[mountainclmbr]

I have not seen accurate reports about the fatigue cracks. It is not mentioned if it is in the pavement or in the I-beams in reports I have read. Pavement cracks are to be expected, especially since the iron expands and contracts with temperature. I-beam cracks are another matter since they provide the structual support, the pavement does not. I hope that lessons are learned that will improve safety in the future.

[DJJ]

They were caulking fatigue cracks?? 

[Sindawe]

They were caulking fatigue cracks??

Calking is sorta like glue, is it not?  And glue holds stuff together, right?

Sounds like a reasonable fix to me.

/sarcasm

[Bigjake]

Calking is sorta like glue, is it not?  And glue holds stuff together, right?

Sounds like a reasonable fix to me.

/sarcasm

obviously,  this called for liberal amounts of duct tape, and the .gov failed.

[never_retreat]

No no no you cant use duct tape on structual cracks you have to use liquid nails. Everyone knows you can glue trash to trash with liquid nails.

[Ben]

Have you guys noticed that ANYTHING and EVERYTHING gets blamed on Bush?

Good news! Bill O'Reilly is not blaming Bush. He's blaming the weight of SUVs (seriously).

[Vile Nylons]

Pretty amazing how many people survived the fall. Sad about those that didn't.

[DustinD]

As if a thousand pound difference from one vehicle to the next would matter compared to the weight of the bridge.

I hope there are some seriously huge lawsuits over this.

[Manedwolf]

Hey, look at Boston, where they secured multi-ton concrete slabs with cables...epoxied into the roof. In a thing that vibrates as traffic goes by.



I find it a healthy outlook to assume that any lowest-bidder public work is going to try to kill you, and be observant and supicious of it whenever you have to use it.

[Antibubba]

I was listening to an interview with one of the survivors this morning.  He wasn't hysterical as he recalled it, but there was this, I don't know how to describe it, edge, in his voice, the kind of thing you hear from someone who faced death and didn't have the time to realize it before it ended and he lived.  It was hard to listen to, and impossible to stop listening to at the same time.  Pre-PTSD.

I sat and listened and thought how valuable it was to hear how he reacted to this, while at the same time feeling like I had just overheard something terribly private, a secret.

Hold on, it was this guy:

Peter Siddons, who was crossing the bridge on his way home from work when it collapsed, told NPR he heard a boom and saw the section of bridge disappear in front of him.

                       
"My nose was down and the front of my car was going down and I thought this was it, I'm off the bridge and it's over," he said.

                       
"But, then, it's surreal after that & you don't know what to do," he said. "You're looking for something, but you're not sure what you're looking for. You're looking for closure. I don't know. You're not ready to leave."

It really struck a nerve.  Still does 15+ hours later.

Found it.  You can hear it here: http://www.npr.org/templates/story/story.php?storyId=12446837

Click on the "LISTEN" button.