Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

News Bridge collapses in Washington state

  1. May 23, 2013 #1

    George Jones

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    http://usnews.nbcnews.com/_news/201...in-washington-state-cars-people-in-water?lite
     
  2. jcsd
  3. May 23, 2013 #2
    I remember when that bridge collapsed in Minneapolis. How scary!
     
  4. May 23, 2013 #3

    George Jones

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    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.
     
  5. May 24, 2013 #4

    DrDu

    User Avatar
    Science Advisor

  6. May 24, 2013 #5

    Monique

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What is the maintenance state of bridges in the US? I've heard they are neglected due to the economic situation?
     
  7. May 24, 2013 #6

    jim mcnamara

    User Avatar

    Staff: Mentor

  8. May 24, 2013 #7

    jtbell

    User Avatar

    Staff: Mentor

    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.
     
  9. May 24, 2013 #8

    Astronuc

    User Avatar

    Staff: Mentor

    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.
     
  10. May 24, 2013 #9

    russ_watters

    User Avatar

    Staff: Mentor

    http://www.cnn.com/2013/05/24/us/washington-bridge-collapse/index.html
    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.
    http://en.wikipedia.org/wiki/I-35W_Mississippi_River_bridge#Investigation

    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.
     
  11. May 24, 2013 #10

    lisab

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    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:

    http://usnews.nbcnews.com/_news/201...nto-river-after-wash-i-5-bridge-collapse?lite

    Btw, for those who aren't familiar with the local geography: that freeway is the main link between Seattle and Vancouver, BC.
     
  12. May 24, 2013 #11

    Monique

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Thanks for the clarification!
     
  13. May 24, 2013 #12
    Everything you wanted to know about bridge / inspection
    http://www.in.gov/dot/div/contracts/standards/bridge/inspector_manual/

    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.
     
  14. May 24, 2013 #13

    OCR

    User Avatar

    http://en.wikipedia.org/wiki/I-5_Skagit_River_Bridge_collapse
    http://www.washingtonpost.com/national/state-patrol-i-5-bridge-over-skagit-river-collapses-in-nw-wash-vehicles-people-in-water/2013/05/23/ef618aaa-c41c-11e2-9642-a56177f1cdf7_story_1.html [Broken]

    Negligence?

    How about diminished...

    http://en.wikipedia.org/wiki/Situation_awareness#Situation_awareness_in_team_operations

    Usually plays out that way, IMO.



    OCR
     
    Last edited by a moderator: May 6, 2017
  15. May 24, 2013 #14

    OCR

    User Avatar

    Negligence...

    A close call.jpg

    Loss of SA...

    OCR still reading.jpg

    Transcendent moments...

    diggers preflight check.jpg



    OCR... lol
     
  16. May 24, 2013 #15

    lisab

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    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.
     
  17. May 25, 2013 #16

    morrobay

    User Avatar
    Gold Member

    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.
     
  18. May 25, 2013 #17

    Astronuc

    User Avatar

    Staff: Mentor

    http://www.nytimes.com/video/2013/0...eadlines&emc=edit_th_20130525#100000002245042

    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.
     
  19. May 25, 2013 #18

    jim hardy

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    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.
    05230167&Ref=AR&MaxW=640&Border=0&I-5-bridge-collapses-near-Seattle-throwing-vehicles-into-river.jpg
    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.
     
    Last edited by a moderator: May 6, 2017
  20. May 25, 2013 #19

    russ_watters

    User Avatar

    Staff: Mentor

    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.)
     
  21. May 25, 2013 #20
    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............
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Bridge collapses in Washington state
  1. Washington's Madam (Replies: 13)

Loading...