Cedars Posted August 6, 2007 Report Share Posted August 6, 2007 Its been all over the news so I wont recount those details. The MN Dept of Transportation has posted the last full inspection report from 2006. If one of you engineer types wants to read it: http://www.dot.state.mn.us/hottopics/35w/06_br_%209340%20.pdf If you find something that sticks out, I am interested in hearing it. Personally I have avoided this bridge as much as possible since last year as I didnt think it was safe. Last trip over this bridge (actually last 3 trips over) I went across with seat belt fastened and window rolled down. Luckily I havent found myself on it since October 2006. I've been to Minneapolis since then, but I went around this bridge. I used to travel it a lot i the past and always felt secure. Keywords in what I have read so far that cause me alarm are things like "tack welds" "cracks at negative movement regions". I know what tack welds are. I am interpreting 'cracks at negative movement regions' as cracks forming where the region is not supposed to be moving, indicating some kind of stress is causing movement. At page 17 begins pictures of joints and beams. Quote Link to comment Share on other sites More sharing options...
Mercedes Benzene Posted August 6, 2007 Report Share Posted August 6, 2007 Obviously, I'm not an engineer, but by simply thumbing through that report, it's obvious that things were pretty messed up with this bridge. There seemed to be so many things wrong with it that I'm not surprised at what happened to it. Now, from what I heard, there were construction crews working at the time of collapse. Were those construction personel working to try and correct some of the flaws outlined by this report? No matter what happened in MN, it's clear that the United States needs to take a serious look at the existing infrastructure... and attempt to fix any problems that can be seen.On the note of bridges, there's something in particular that I'm concerned about in my area. Northeast from me, there are two parallel spans of bridges that cross the Chesapeake Bay. One of the spans was built in the 50s, and the other was built in the early 70s. I've noticed however, that the newer span looks like crap. Riding in my boat under the bridges, I notice that it's very rusty, and I've even seen stuff falling off into the water below.It's not often that I actually travel over the bridges, but it's very disconcerting to know that they (and many other bridges accross the US for that matter) could be in danger of the same problems the MN bridge faced; and that many lives could be in danger. Quote Link to comment Share on other sites More sharing options...
Cedars Posted August 6, 2007 Author Report Share Posted August 6, 2007 Obviously, I'm not an engineer, but by simply thumbing through that report, it's obvious that things were pretty messed up with this bridge. There seemed to be so many things wrong with it that I'm not surprised at what happened to it. Now, from what I heard, there were construction crews working at the time of collapse. Were those construction personel working to try and correct some of the flaws outlined by this report? No matter what happened in MN, it's clear that the United States needs to take a serious look at the existing infrastructure... and attempt to fix any problems that can be seen.On the note of bridges, there's something in particular that I'm concerned about in my area. Northeast from me, there are two parallel spans of bridges that cross the Chesapeake Bay. One of the spans was built in the 50s, and the other was built in the early 70s. I've noticed however, that the newer span looks like crap. Riding in my boat under the bridges, I notice that it's very rusty, and I've even seen stuff falling off into the water below.It's not often that I actually travel over the bridges, but it's very disconcerting to know that they (and many other bridges accross the US for that matter) could be in danger of the same problems the MN bridge faced; and that many lives could be in danger. The crew was working on replacing concrete decking. It involved jackhammering out concrete and cutting rebar and the replacement of that. It would not have impacted a stable bridge from what I know of that type of construction. This bridge was supposed to be able to hold 18 wheelers along its entire length and not compromise the structure. Traffic was reduced by half for the construction, as best as I can gather. In the first days following the collapse, there were two major bridges listed on MSNBC as in worse shape than this one, carrying comparable traffic. One was in oregon or washington state (I forget which) and the other was in New Jersey (the one featured in the Sopranos). There is only one other bridge in Minnesota I do not drive on (probably more I shouldnt). I dont normally fear bridges but the one that collapsed was one I avoided and took measures when crossing because I did fear total failure. As far as a newer bridge being better? We have one in Minnesota, just south of st Paul that they were not even able to finish building and have to start over on. Pilings driven in were off by feet, pounded in crooked and a host of other issues. Low bid.... ya get what you pay for.... You gotta go with your gut feeling on this issue. It seems the government is choosing to err on the side of pennies per citizen rather than erring for public safety. Quote Link to comment Share on other sites More sharing options...
Edella Posted August 6, 2007 Report Share Posted August 6, 2007 Unlike Cedars, I never clued in to anything that would suggest the bridge was dangerous. I've crossed this bridge hundreds of times in the ten years I've lived in Minneapolis and never thought twice about it. I live about a mile and a half away from the bridge in N.E. Minneapolis, and at the time of the collapse the power went out briefly and my internet connection was down for two days. I'm fairly certain I heard the collapse, but I live near a railway station (where loud metallic crashes are frequent) and thought nothing of it. Initial reports on the radio led me to believe it was minor. It was only after a call from a friend (calling to see if I was o.k.) that I became aware of the severity of it. Luckily, no one I know - including Cedars :) was hurt or killed. I haven't gone down to the site yet, I imagine the authorities have had their hands full with gawkers, but according to the Pioneer Press, the stone arch bridge, a pedestrian bridge crossing the Mississippi very near 35 W, will open today. My morbid curiosity compels me to take a look. BTW- Cedars, what clued you in to the fact that the bridge was unsafe? Quote Link to comment Share on other sites More sharing options...
Turtle Posted August 6, 2007 Report Share Posted August 6, 2007 ...In the first days following the collapse, there were two major bridges listed on MSNBC as in worse shape than this one, carrying comparable traffic. One was in oregon or washington state (I forget which) and the other was in New Jersey (the one featured in the Sopranos). ... helpful links>>> Oregon bridges >> Deficient major bridges in Oregon - Bridge Collapse - MSNBC.com Washington bridges >> Deficient major bridges in Washington - Bridge Collapse - MSNBC.com bridges state-by-state >> - Bridge Collapse - MSNBC.com Across the Columbia River from me, Portland Oregon has 2 steel-truss-deck type bridges crossing the Willamette River. One is the Morrison, and the MSNBC report says ( A value of 100 represents an entirely sufficient bridge and a zero represents a deficient bridge.; ratings in bold) 54.7 9350 PORTLAND MULTNOMAH OR 99E (HWY 001E) EAST END MORRISON BR O 82.5 9326 PORTLAND MULTNOMAH CITY STREETS & PARK WEST END MORRISON BR Interesting that they divide the bridge into 2 sections for ratings.?? :shrug: I think that in general the civil engineers do a good job with the resources governments allot them. As always, we have room for improvement. Register and vote. Communicate to your government representatives your concerns. :) Quote Link to comment Share on other sites More sharing options...
Zythryn Posted August 6, 2007 Report Share Posted August 6, 2007 My wife has a co-worker that was on the north edge of the bridge when it went down. The section he was on only fell from one end so he was able to 'gun it' and get onto level ground again.Our society is too blaah about anything that isn't sensationaly. "If it aint broke, don't fix it". Well, what if it is GOING to break, wait till it does?Most of the disaster in New Orleans could have been prevented if enough work had been done on the levees to prevent the breaks.The collapse of a major interstate through the middle of Minneapolis could have (most likely) been prevented with a more thorough repair/replacement schedule.California learned to build their highways and buildings in preperation for earthquakes. But only after MAJOR catastrophies.Problem is, I am a cynic, I don't think this will stay in peoples minds very long. Most likely the next time a celebrity gets thrown in jail it will be less of a concern for the majority of Americans:crying: Quote Link to comment Share on other sites More sharing options...
Cedars Posted August 6, 2007 Author Report Share Posted August 6, 2007 . Luckily, no one I know - including Cedars :) was hurt or killed. No one I know has been hurt or lost. I looked for both you and Zythryn to log in after this event. BTW- Cedars, what clued you in to the fact that the bridge was unsafe? I used to use that bridge frequently. I even lived in Minneapolis for a while and used it Monday evening thru Thursday afternoon commuting to work (second shift). But that was 20+ years ago. For the last few years I had not been on that bridge much. In April 2006 a family event caused me to travel that bridge. I couldnt believe how much it moved as we crossed on a saturday afternoon. Deteriorated was a word that went through my mind. But I didnt think it was in that bad of a condition and I did not feel it was too dangerous to use again. Then in August 2006 I was driving a relative down. We were southbound in a lane that left one lane on my right. We just about to enter the last span before we actually are over the water or on the last span before the water. The bridge began to lurch. Not sway, violently lurch. 3 sharp lurches, one of which about threw me into the right lane. I had to fight with the car to keep it in my lane. The whole incident lasted probably 5 seconds, no more than 10 seconds. I slammed on the brakes and slowed to a crawl, seriously considering ways to get off that bridge. The rest of the trip across the bridge took forever.... I told my passenger several things, including that "I dont know if we were gonna make it across", "Bridges are not supposed to move like that, we're not taking this way home", and finally "that bridge is dangerous". The three times I have been on that bridge since, it has not acted that sharply. I have thought about all the people who used it each day and didnt feel the change like I did. Too used to its movement. Of the various news reports coming out since the collapse, I think the one that red-flags it for me the most is the discussion of shoring up the bridge by bolting and welding plates, carried on in Jan 2007. The DOT said they felt having to drill that many holes would compromise the structure too much (or something like that). I thought, if the repairs are so extensive that you believe the bridge would be worse off, how can you justify keeping it open? Right there, they were saying the bridge was beyond repair. Quote Link to comment Share on other sites More sharing options...
Cedars Posted August 6, 2007 Author Report Share Posted August 6, 2007 helpful links>>> Oregon bridges >> Deficient major bridges in Oregon - Bridge Collapse - MSNBC.com Washington bridges >> Deficient major bridges in Washington - Bridge Collapse - MSNBC.com bridges state-by-state >> - Bridge Collapse - MSNBC.com Across the Columbia River from me, Portland Oregon has 2 steel-truss-deck type bridges crossing the Willamette River. One is the Morrison, and the MSNBC report says Interesting that they divide the bridge into 2 sections for ratings.?? :shrug: I think that in general the civil engineers do a good job with the resources governments allot them. As always, we have room for improvement. Register and vote. Communicate to your government representatives your concerns. :) I have searched a bit today for more info on the report covering those two bridges. I cannot find it. With all the news and stuff I have been watching, its hard for me to say which one it was that talked of the NJ and the other bridge. Reading over the links, the Snake river and the Green river popped out as familiar. I am thinking it was a Washington bridge rather than Oregon, mentioned in the report I referred to. Quote Link to comment Share on other sites More sharing options...
Buffy Posted August 9, 2007 Report Share Posted August 9, 2007 The New York Times has an article today (you many need to register to read this) talking about how the bridge actually may have had *design flaws*:...The National Transportation Safety Board’s investigation is months from completion, and officials in Washington said they were still working to confirm the design flaw in the so-called gusset plates and what, if any, role they had in the collapse. Still, in making public their suspicion about a flaw, the investigators were signaling they considered it a potentially crucial discovery and also a safety concern for other bridges. Gusset plates are used in the construction of many bridges, not just those with a similar design to the one here....Concerns about the plates emerged not from the waters of the Mississippi River here, where workers have only begun to remove cars and the wreckage with cranes, but from scrutiny of the vast design records related to the steel truss bridge....If those who designed the bridge in 1964 miscalculated the loads and used metal parts that were too weak for the job, it would recast the national debate that has emerged since the collapse a week ago, about whether enough attention has been paid to maintenance, and raises the possibility that the bridge was structurally deficient from the day it opened. It does not explain, however, why the bridge stood for 40 years before collapsing....Federal authorities said one added stress on the gusset plates may have been the weight of construction equipment and nearly 100 tons of gravel on the bridge, where maintenance work was proceeding when the collapse occurred. Obviously there's a lot more to be discovered, but it shows the dangers of jumping to conclusions--in this case that ignoring "maintenance of infrastructure" is the culprit--is always dicey. More data please,Buffy Quote Link to comment Share on other sites More sharing options...
Cedars Posted August 12, 2007 Author Report Share Posted August 12, 2007 The New York Times has an article today (you many need to register to read this) talking about how the bridge actually may have had *design flaws*: Obviously there's a lot more to be discovered, but it shows the dangers of jumping to conclusions--in this case that ignoring "maintenance of infrastructure" is the culprit--is always dicey. More data please,Buffy Last week sometime they had a snippet of the press conference given by Mark Rosenker from the NTSB. This guy is very animated when giving a conference and I have yet to be disapointed by one hes giving. In regards to a question regarding the above report, he said "Folks please to not try this at home". He was referring to trying to figure out the cause of the collapse. In reading over comments posted regarding the collapse, such as comments at local TV news spots, or newpapers, there have been a couple of people reporting "swaying" or other movements of the bridge that they were very uncomfortable with. One was two weeks before the collapse, one writer spoke of an incident on Fathers day. Today I visited with a former employee of the MTC (public bus system) and asked about the bridge. He told me he called some of the people still working there and was told they were instructed to avoid that bridge due to the construction in an effort to keep the buses on time. It was a departmental decision and was based on keeping routes running on time, not due to fear of the bridge itself. He said otherwise, on a normal route day, there would have been a very real possibility a bus would have been on that bridge at that time of day. Quote Link to comment Share on other sites More sharing options...
Cedars Posted January 16, 2008 Author Report Share Posted January 16, 2008 Heres the NTSB pdf interim report that the news reports yesterday were based on. Some good diagrams and formulas regarding stress.http://www.ntsb.gov/Recs/letters/2008/H08_1_Design_Adequacy_Report.pdf A diagram of the full bridge span:http://www.ntsb.gov/Pressrel/2008/PressConf.pdf NTSB Homepage:National Transportation Safety Board I still havent been to the bridge area. My travels to the twin cities since this happened have allowed me to avoid that area. Quote Link to comment Share on other sites More sharing options...
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