All posts in the topic Central Corridor Math (Short link)
Summary
- There are 3 posts — by 3 authors — in this topic.
- Latest post made by Dean Sheldon at Nov 18 11:44 UTC
The National Transportation Safety Board (NTSB) has discovered a critical design flaw that contributed to the collapse of the 35W bridge. Apparently, the company that designed the bridge failed to calculate the load capacity of the metal plates that held the bridge together. According to an MPR report, http://minnesota.publicradio.org/display/web/2008/11/14/ntsb_day_1/ In 1962 when the bridge was designed, the size of the gusset plates was likely not calculated. Investigators could not find any documents from the original design to show planners had calculated how thick the gussets needed to be. Also, according to the NTSB report, State and Federal agencies were responsible for approving the critically flawed bridge design. According to an AP report: The bridge was designed by the engineering firm of Sverdrup & Parcel, which was acquired in 1999 by Jacobs Engineering Group Inc. of Pasadena, Calif. http://www.idahostatesman.com/aptopstories/story/570606.html According to Robin Caufman at the Met. Council, Jacobs Engineering is the Project Management Oversight Consultant (PMOC) that the FTA hired to oversee the (Central Corridor) project. This raises the following questions: 1) Whos paying Jacobs Engineering for consulting work on the Central Corridor Project? 2) How much? 3) Is the money coming out of the 50% federal matching grant for the project? 4) Is Jacobs Engineering getting paid to essentially rubber stamp the $100 million or so Met. Council plan? 5) After State and Federal agencies approve running a new light-rail line over the obsolete, 50-year old Washington Avenue Bridge, will the consultants at Jacobs take their multi-million dollar consulting fees and simply morph into another consulting firm the way that Sverdrup & Parcel was acquired by Jacobs?
Yup the NTSB blamed the designers. What did you expect? I certainly don't know what the engineering standards were 40+ years ago for this type of bridge. I also don't know what the estimated life was designed into the bridge. I do know that absent the weight of a 747 in one part of the bridge, it would not have collapsed. Can someone with a Civil Engineering background explain this report to us? Mike Fratto Payne Phalen Please help those who don't get enough to eat. http://oyh.org http://hungersolutions.org The future depends more on what we do between now and then Than what we did in the past.
Sheldon,
I am interested in reading the full NTSB report. I find it hard to believe they
can really blame the original designs. 1) the bridge was 40 some years old. The
guesset plates had held just fine. 2) the bridge deck was increased in '77
adding significant weight 3) there was a concentrated point load (heavy
materials during the repair) when designs are generally for distributed loads.
More questions
1) Are we headed towards another bridge collapse when a fully loaded LRT train
happens to be on the upper level at the exact same time a half dozen fully
loaded gravel trucks are on the lower level?
2) Will Jacobs Eng., the state highway people, and the Fed highway people learn
from their mistakes on the 35W bridge? That is, will they actually measure all
the pieces and re-calculate all the components of the old bridge?
3) Will funds for this new job to Jacobs Engineering be held in escrow until
all settlements against the 35W bridge design job they acquired have been
settled?
Dean Sheldon
----- Original Message -----
From: sheldon gitis
To: <email obscured> ; <email obscured>
Sent: Monday, November 17, 2008 2:45 PM
Subject: [SPIF] Central Corridor Math
The National Transportation Safety Board (NTSB) has discovered a critical
design flaw that contributed to the collapse of the 35W bridge. Apparently, the