December 8, 2007

November 22, 2007

November 21, 2007

November 16, 2007

November 12, 2007

November 2, 2007

  • Perhaps this is ”the straw that broke the camels back”.  My focus is what caused the undetected weaking of the bridge.  From the day after the collapse I cited probably pin/bearings/hinges problems that would not allow the bridge to expand and contract.  Like a badly overlaoded vehicle this will take it’s toll over time.  

     

    There are simple and cheap measurment tools that can detect if these pins/bearings/hinges are funtioning properly.  Basically combine a simple laser ruler with a mirror and couple it to a cellphone.  Have it phone in data on the  distance of the flex and have a computor compare that to expected paramenters.

    To visualise this imagine an open door.  You measure the distance between the latch and the base plate.  In the case of a bridge this should be a smooth and predictable action.  As the girders expand and contract with temperature this distance should change and is thus measurable.  This is predictable and a computor can record this and cross check it against expected “flex”. 

    I could set up a manual demo for under $10.  Obviously a more “robust” system and a computor monitoring systems would cost more but it can be done at relatively modest cost.  If the unit fails it will not be sending back data within parameters so it will be “flagged”.


    http://www.startribune.com/10204/story/1523652.html

    Bridge collapse: ‘Working theory’ blames design, weight
    U.S. Transportation Secretary Mary Peters said that investigators have a “working theory” of why the I-35W bridge collapsed: a poorly designed gusset plate and excessive weight on the bridge that day.
    By Mike Kaszuba and Kevin Diaz, Star Tribune
    Last update: November 01, 2007 – 11:42 PM
    The top federal transportation official said that investigators have a “working theory” of why the 35W bridge collapsed in August: a poorly designed metal component called a gusset plate and excessive weight on the bridge that day.
    U.S. Transportation Secretary Mary Peters’ comments Thursday mirrored statements she made in August, a week after the collapse, and like her previous comments immediately led to controversy. The National Transportation Safety Board, which is investigating the collapse, has said a formal finding will not be available for at least a year.
    Sen. Steve Murphy, chairman of the Senate Transportation Committee, said Peters told a gathering Thursday in Washington, D.C., that he attended that “a finding of fault was not going to be lack of inspection or lack of maintenance” by state officials.
    “I think it taints the findings,” he said.
    But a spokesman for Peters said Murphy’s account of her comments was inaccurate.
    “What she said is, look, I’m not going to prejudge what the NTSB is going to find, but the working theory that they are operating on, and this has been in the news for about two months now, is that there was a combination of a gusset plate and too much weight placed on a certain part of the bridge,” spokesman Brian Turmail said.
    “Certainly, the NTSB would want to look into whether lack of maintenance was a factor in the collapse of the bridge,” he said. But Turmail added that “the working theory at the NTSB is that it is not a lack of inspections, but a design flaw and weight.”
    Later Thursday, Rep. Ron Erhardt, R-Edina, confirmed Murphy’s account. “Murphy was sitting behind me and I turned to him and said, ‘What is this?’” Erhardt said. “To hear that it wasn’t maintenance or inspection, I thought, ‘What the hell?’ I remembered early reports about the gussets and I thought, what is that but lack of maintenance?”
    Peters’ remarks came during a formal address to the White House Transportation Legislative Leaders Summit.
    A design flaw would give administration critics less of an opening to hold current officials at the Minnesota Department of Transportation or Gov. Tim Pawlenty responsible.
    “It’s true, yeah, we are looking at the design issues and the gusset plates and the weight of the construction materials and equipment on the bridge,” NTSB spokesman Peter Knudson said. “We’re also looking at the maintenance and repair history. We’re looking at the de-icing fluids — any role they may have played. We basically haven’t ruled anything out yet.”
    Staff writer Patricia Lopez contributed to this report.
    © 2007 Star Tribune. All rights reserved.

October 24, 2007

October 18, 2007

  • Repost of my August 02 entry which speculated hinges pin (bearings).

    Thursday, August 02, 2007

    My thoughts on the 35W bridge collapse here in Minneapolis

     

    Pretty much “wall to wall” coverage on local TV.  Basically pretty responsible and respectful coverage.  The official death toll is down to four but that is only post medical examiner.  20 to 30 cars submerged.  No extraction and 20 to 40 people “missing”.

    The emergency response process seemed to work very well and will be a textbook model on how it should be done.  One big factor was a metro wide emergency communications compatibility project.  That started maybe twenty-five years ago.  One of the regulars in the Hennepin County mainframe computer room when I worked there was deeply involved in this and shared updates.  Five years ago when I left the computer room the process was basically complete.  They basically “play” with the system at the Minnesota State Fair, which is in the middle of the cities and borrow a lot of cops and cop cars for the event.  This seemed like the first “real life” test and the system seemed to have worked well.  That is reassuring for the Republican Convention next year.

    As for the cause of the collapse, that will take time but I’ll bet on the “hinge pins”.  If you watch the footage you will notice that the bridge pylons are rather thin and “spindlly” looking.  The basic idea was that the the bridge would “rock” on what are basically giant “hinges”.  A few years back they closed the bridge for a weekend to jack it up and replace a few of these “hinge” pins that have sieze. That sound to me like the key culprit.  It’s like that “creaky” barn, boathouse or cellar door.  It cause tremendous stresses.  My guess is that the NTSB investigators will first go after these “hinges”.  You cut them open and look for corrosion fusion. 

    As for my theory, I know the basics but am not an engineer, some of the “hinges” likely froze up so the main steel arch, a bit under 500 feet got compressed and stressed.  A week or ago we had a cold front move through that was very dramatic.  It had sudden heavy rain and a temperature change of something like 30 F in less than an hour.  The rain and cold would contract the steel arch quickly and if the “hinges” were stuck this could stress the structure.

    On the day of the collapse it got up to 97 and they were pouring concrete for resurfacing.  Curing concrete generates a lot of heat.   A storefront came by at that time.  It apparently did not drop much if any rain downtown but it caused a quick temperature drop.  This might have been “the straw that broke the camel back”.

    An interesting phenomena I heard about on talk radio were people calling in saying that they got calls or emails from relatives and friends around the world asking if they were OK with minutes of when the collapse occurred.  Lot’s of these.  Apparently the story went “global” in less than an hour.

    The area around the bridge was the first wired for the new Minneapolis “WiFi”.  They gave the first 12 hours open access and are apparently letting police, ect have priority.     

    1:03 PM – email it

  • http://www.minnesotademocratsexposed.com/2007/10/18/star-tribune-brian-mcclung-federal-regs-make-bridge-information-confidential/#comments

    STAR TRIBUNE: “BRIAN MCCLUNG: FEDERAL REGS MAKE BRIDGE INFORMATION CONFIDENTIAL”

    By Michael B. Brodkorb | October 18, 2007

    This commentary from Governor Pawlenty’s communications director Brian McClung is a must read. 

    ### 

    “This week, Star Tribune reporters and editors may have outdone themselves in crafting controversy and intrigue where none exists.

    In a front-page article Sunday and in an editorial on Tuesday (“Seeking answers from bridge probes”), the newspaper creates the impression that state officials are willfully intending to keep “secret” a report that will be prepared by outside forensic investigation experts regarding the causes of the Interstate 35W bridge collapse.

    The truth is much more straightforward, but less controversial than the spin the Strib put on it: Federal regulations require information related to the bridge-collapse investigation to be nonpublic until the National Transportation Safety Board (NTSB) approves its release. State officials are not voluntarily choosing to keep the data private; they are simply following federal regulations, which preempt state data practices law. When the law allows, we’ll make all available information public.

    If the newspaper has a beef here, it should be with that law. A case can be made for changing federal regulations to allow for more openness. But reporters and editorial writers should not be surprised that state officials will indeed follow the law.” Source: Star Tribune, October 16, 2007

    Click here for the complete story. 

    Topics: Uncategorized |

    One Response to “STAR TRIBUNE: “BRIAN MCCLUNG: FEDERAL REGS MAKE BRIDGE INFORMATION CONFIDENTIAL””

    1. Greg Lang Says:
      October 18th, 2007 at 4:40 pm

      I’ll cross-post this http://riverbridgecollapse.com The Strib has since reported that the bridge bearings/hinges appeared to be sticking. I believe that I was the first to publicly post that this could be a significant factor in the bridge collapse.

      Here is a paste of an email I sent to someone watching this.

      “New Minneapolis Star Tribune story says my main bridge culprits, hinges/bearing were likely stuck but they haven’t opened them yet. The other, more immediate cause of bridge failure was a lower “gusset plate”. This is a steel plate that steel beams are bolted to. One was perfectly designed to catch dirt, salt and mositure, much like those old cars that, in the Northern rust zones would have the fenders rust at the bottom. Essentially, the stuck bearings/hinges would not let the bridge expand or contract with temperature changes. The “gusset plates” took the stress. I didn’t know the specifics of the gusset plates but I believe I was the first to point out stuck bearings/hinges and the stress they could cause. More later, I can describe this in great detail.

October 12, 2007

  • Anti-Strib: Pier 6

    I meant to post this to my bridge collapse blog http://riverbridgecollapse.com The link to LRT is admittedly weak but the new I35W bridge has provisions for future light rail, some extra space in the center lanes.

    When they were building the Metrodome they found a huge granite rock, maybe 10 x 15 feet during the excavation. This is glacial till and not that unusual in the area. This presumed that the weight of the pier cased the giant granite rock to shift or subside. I doubt it because this could have been very easily measured after the bridge collapse.

    Anti-Strib: Pier 6

    http://anti-strib.blogspot.com/2007/10/pier-6.html
    Pier 6
    Everyone knows that I canceled my dead tree edition of the RED Rag quite some time ago because I was tired of supporting the DFL here. So, I was not surprised to see that the RED Rag didn’t bother to even comment on the Tom Lyden’s report on Fox 9 last night opn their website…being that it didn’t fit into the Carol Molnau and Republican bashing agenda. Instead they have decided to run a piece about their second favorite Senator, Busty Amy Klobuchar. (
    You see, Tom Lyden did something that the DFL seems unable to do prior to finger pointing in the 35W bridge collapse…he did some investigating, and what he found should be heard by everyone man, woman and child throughout the US today. And it has nothing to do with Lt. Governor Molnau, has nothing to do with a lack of money being spent today on roads…it has to do with a decision made way back when the bridge was being built.
    Tom Lyden found an old lawsuit against what we now know as MNDot, by the original bridge construction company, claiming that the bridge could not be built as intended. Pier 6, as it turns out, ran into a problem. As the construction company was drilling down to the bedrock it encountered a rather large problem…granite boulders that stopped the drills right in their tracks. The lawsuit was brought in order to get more money out of the state so that the construction company could deal with the situation…money that the construction would not get.
    The lawsuit was settled out of court, and the documents that would shed light on what was done to address the problem are either missing or incomplete…meaning that it is entirely possible that pier 6, and maybe even pier 7, are resting not of bedrock as needed for a stable structure, but rather on granite boulders. If this is indeed the situation, no amount of funding and no amount of spending today could have stopped the bridge from falling…and it certainly isn’t Carol Molnau’s fault.
    The DFL needs to stop their finger pointing and witch hunt and do some research themselves. If it is found that pier 6 was not built properly, and that it was Carol’s decision back in the 1960’s, then by all means, go after her…but if not, shut your cake hole and wait until the facts are in.
    Did you hear that Sen. Steve Murphy, D-Red Wing?
    posted by Brent at 10/10/2007 07:37:00 AM