I remember when that bridge collapsed in Minneapolis. How scary!
Yes, I remember that, and I remember the 2006 overpass collapse in Montreal.
Yes, very scary. It is unclear if all the people in the vehicles got out alive.
Reminds me of a poem by Theodor Fontane:
What is the maintenance state of bridges in the US? I've heard they are neglected due to the economic situation?
A large number of US bridges are in poor shape and have been that way for a long time -- years.
As far as I can see it is not the current economy that is the root cause, just local governance issues.
One fundamental problem is that highway and bridge maintenance in the US is mostly paid via funds from gasoline taxes, which are assessed at a certain dollar value (which varies between states) per gallon. This leads to two problems:
First, the tax rate is not indexed to inflation, and raising it is politically very unpopular, both at the state and federal levels. The federal gasoline tax has not increased in about twenty years, and states rarely increase theirs.
Second, as cars and trucks become more gasoline-efficient, the amount of gasoline tax collected per vehicle decreases.
This situation has been building up for many years.
From the article
So damage due to collision as well as the design/condition of the bridge may be factors.
It is true that many bridges across the US are in poor condition. The ASCE frequently gives a C or lesser grade for the infrastructure in the US.
Locally it may be true, but it is tough to really say. When the economy tanks, infrastructure spending is one of the easiest way to stimulate it, so there was a huge injection of cash by the federal government into infrastructure in 2009 ($105 Billion).
Major collapses strictly due to deterioration are pretty rare, but certainly age can play a factor even if not the proximate cause. A new bridge could probably better handle getting rammed by a truck than an old bridge. The Minneapolis bridge collapse was caused by a design flaw that was never found, a road surface that had gotten thicker (and heavier) over time and heavy construction equipment sitting on a particularly vulnerable spot. Deterioration probably added a little to that trifecta of faults.
Bridges are so overdesigned that it would be tough for deterioration alone to cause a collapse. I do however remember an I95 overpass shutdown for emergency repairs in Philly a few years ago when an off-duty inspector happened by and noticed a crack that he had inspected previously had widened considerably.
This particular bridge was not structurally insufficient, but it had been classified as "functionally obsolete". In this case, that means was not wide or tall enough for the amount of traffic it's now being required to take. Of course it was adequate when it was built nearly 60 years ago, in 1955.
Ultimately that truck driver is at fault, IMO. When trucks move over-size loads, they are required to know ahead of time what route they need to take. In this case, according to a truck driver witness, if he had been in the next lane over the truck would have cleared easily. Route information is readily available, it looks like this was just negligence.
Unfortunately this bridge is not designed to take a hit like this:
Btw, for those who aren't familiar with the local geography: that freeway is the main link between Seattle and Vancouver, BC.
Thanks for the clarification!
Everything you wanted to know about bridge / inspection
Fracture critical means that the bridge design is such that it lacks redundancy for members and its connections in tension. Tension members could develop fatigue cracks over years of traffic use, and on failure the path load is not taken up by another member.
I would be surprised that a hit from a vehicle would be enough to bring the bridge down, without some member already having become deficient through age and not having being noticed by inspection because of inaccessability for a thorough examination.
How about diminished...
Usually plays out that way, IMO.
Loss of SA...
Definitely a loss of SA played into this. But there were contributing factors, too.
I heard a live interview of another truck driver who was on the bridge - I can't find a transcript of it, I heard it live on local TV over the net. But that driver said he was one lane over, behind the pilot car, but ahead of the oversize truck. He saw the pilot car safety antenna hit the bridge, but he realized the oversize truck was following too close to his pilot car to stop or change course. He watched the collision in his rear view, then saw the girders fall...then he drove like hell to get off the bridge.
So if that driver's story was accurate, the oversize truck was following too close to his pilot car.
According to a TV news report 25% of bridges in the U.S. are structurally deficient . Regarding
the economic situation : It seems the roads and bridges in Afghanistan are the priority.
Remember it was Bush who diverted funds for levy upgrades by the army corps of engineers in Louisiana, for Iraq war funding. Which resulted in excess hurricane Katrina damage.
According to the video from NYTimes, in some states, the stimulus funds were used to replace funds already allocated for projects.
Also in the video, it is mentioned that 10 years ago, the ASCE indicated the cost to fix infrastructure in the US would be ~$1.3 trillion, and now it would be ~$3.6 trillion. It would appear that $105 billion would be inadequate.
In our area, we saw some road work (e.g., paving or repaving of roads), and the replacements of some old bridges. But that is a drop in the bucket compared to the work that needs to be done.
My most vivid memory of the Minneapolis bridge it the striking difference in design between it and the one just behind it, presumably older.
That concrete bridge is in compression, that is all its parts are trying to push themselves together.
A trussed steel bridge is largely in tension, that is its parts are trying trying to separate from one another.
courtesy http://www.freep.com/article/20130523/NEWS07/305230167/I-5-bridge-collapses-NW-Washington-people-water [Broken]
I like designs where rather than hold Mother Nature at bay, the engineers enlist her aid.
Understood, yes, the stimulus funds for infrastructure were in general not used for heavy infrastructure projects. One reason is that the money was supposed to be spent quickly, and there really aren't many unfunded "shovel ready" projects. It takes years and costs millions of dollars to design a bridge and it isn't like there are a stack of designed and approved bridge plans laying around ready to execute.
So much of the funding was spent on easy to execute maintenance things such as re-paving roads that didn't really need to be repaved (I saw several in my area).
That wasn't really my point though; my point was just that are issues aren't because of the recent economic issues, they are because of long-term "neglect". (I put "neglect" in quotes because I think the problems while worthy of attention are somewhat overblown.)
Pilot vehicles can be no closer than 100 metres , and no farther than 300 metres.
To witness the antenna hit the bridge and then in a rear view mirror see the truck hit the bridge one lane over and conclude that the distance was too close ............... and still keep himself in a straight line............
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