Wednesday, August 22, 2007
The anti-icing system used on the I-35 W bridge sprays an anti-icing chemical onto the concrete bridge deck when sensors and information from the Road Weather Information System tell it that hazardous conditions are imminent. The anti-icing chemical is potassium acetate. The sensors are ground and deck surface sensors that measure temperature and moisture, and sensors to measure ice formation. The Road Weather Information System are weather stations that measure air temperature and have optical precipitation sensors to detect rain, snow, and sleet. Read the report of the anti-icing system at:
View drawing showing the layout of the anti-icing system on the I-35 bridge at: http://www.dot.state.mn.us/i35wbridge/drawings/BR9340%20Thawspray%20System.pdf
The Minnesota State Senate Transportation Budget & Policy Division and the State House Transportation Finance Division held a joint public hearing on August 15, 2007 on the I-35 W bridge collapse. During that hearing, the members of the Divisions asked Minnesota DOT (MN-DOT) many questions that MN-DOT needed time to respond. MN-DOT has responded to those inquiries and a letter from MN-DOT summarizing the questions and providing the answers is available at:
MN-DOT has provided some additional information about the Municipal Consent process. This is the law in Minnesota that requires MN-DOT to obtain "municipal consent" from the municipality involved when the highway project alters access, increases or reduces traffic capacity (for example, increasing or reducing the number of traffic lanes), or requires acquisition of permanent right-of-way. View flow chart of the municipal consent process at:
View timeline of the municipal consent process at:
MN-DOT has provided information related to their plans for funding the new I-35 W replacement bridge. Abby McKenzie, MN-DOT's Director of the Office of Investment Management, testified about these funding plans at the Minnesota State Senate Transportation Budget & Policy Division and State House Transportation Finance Division joint public hearing on August 15, 2007. View McKenzie's testimony at:
MN-DOT has also provided a list of the professional and technical contracts awarded to date associated with the bridge collapse recovery efforts, bridge collapse investigation, environmental concerns, and new I-35 W bridge replacement. View the list at:
The Federal Emergency Management Agency (FEMA) has issued a press release concerning the I-35 W bridge collapse and federal aid programs that are available. In the press release FEMA states that "Initial FEMA-administered aid is limited to $5 million." Read FEMA's press release at: http://www.fema.gov/news/newsrelease.fema?id=38970.
In an unrelated, but important development, MN-DOT closed a bridge today. The Highway 11 bridge over the Red River sharing the border with North Dakota was closed "after a crack was discovered in a support bracket for a girder during an inspection...". Read the press release concerning this bridge at: http://www.dot.state.mn.us/newsrels/07/08/22-hwa11bridge.html.
[Summary compiled by Susan Lane, ASCE]
Tuesday, August 21, 2007
Monday, August 20, 2007
Minnesota DOT (MN-DOT) has hosted several public meetings on the new I-35W replacement bridge project and has posted handouts from these meetings. MN-DOT has also provided an update on the permits for this project. To date, permits have been received from the Minnesota Department of Natural resources and the U.S. Army Corps of Engineers. Permits are pending from the U.S. Coast Guard and the Minnesota Pollution Control Agency. The handout in the link below provides a full listing of the permits and describes that the additional lanes on the new bridge to accommodate transit may not be for light rail, but could be for a bus rapid transit lane, High Occupancy Toll (HOT) lane, High Occupancy Vehicle (HOV) lane, or some other form of managed lane.
The Minnesota State Legislature has scheduled a second hearing on the new I-35W bridge replacement. The Minnesota Senate Transit Subdivision and the House Transportation Policy and Transit Subcommittee will convene a joint public hearing on August 22, 2007. View the announcement at:
[Summary compiled by Susan Lane, ASCE]
Wednesday, August 15, 2007
MN-DOT's proposed plans for the new I-35 W bridge include 10 lanes for the bridge (up from eight lanes on the previous bridge) with one lane in each direction possibly accommodating transit. Lt. Governor Carol Molnau and Metropolitan Council Chair Peter Bell have sent a letter to Governor Tim Pawlenty describing their assessment for the Governor of the light rail possibility. Their letter states: "At your direction, we have completed our preliminary assessment of the potential for reconstructing the I-35 bridge in a manner that could incorporate a light rail line. For the reasons that follow, we have concluded that the inherent disadvantages of including LRT do not justify the expense and delays that would result from further study." The full letter is available at:
Tuesday, August 14, 2007
[Summary compiled by Susan Lane, ASCE.]
Monday, August 13, 2007
Monday, August 13, 2007--In 2003, the FBI used a $25 million grant to give bomb squads across the nation state-of-the-art computer kits, enabling them to instantly share information about suspected explosives, including weapons of mass destruction.
Four years later, half of the Washington area's squads can't communicate via the $12,000 kits, meant to be taken to the scene of potential catastrophes, because they didn't pick up the monthly wireless bills and maintenance costs initially paid by the FBI. Other squads across the country also have given up using them. See Washington Post article by Mary Beth Sheridan.
Friday, August 10, 2007
Thursday, August 9, 2007
BOSTON, Aug. 8 — The supplier of the epoxy that federal officials have blamed for the collapse of a Big Dig tunnel was indicted today in the death of a motorist crushed by falling ceiling panels.
The company, Powers Fasteners Inc., was charged with one count of involuntary manslaughter. It is the first criminal charge in the tunnel debacle, which killed Milena Del Valle, 38, in July 2006 as she was on her way to the airport. Her death ignited an uproar over the safety of the $15 billion Big Dig, the most expensive single public works project in American history. Story published in the NY Times on August 9, 2007 by Pam Belluck.
Monday, August 6, 2007
The most recent (2006) inspection report of the I-35 W bridge by Minnesota Department of Transportation (MN-DOT), containing detailed descriptions of the cracks found in certain areas of the bridge is available at:
Minnesota DOT has also provided a detailed condition report on the bridge, completed in 2006, includes pictures of the flaws, cracks, and defects in the bridge that the inspectors found. The report is available at: http://www.dot.state.mn.us/i35wbridge/pdfs/06fracture-critical-bridge-inspection_june-2006.pdf
Sunday, August 5, 2007
Pioneer Press (Twin Cities.com)
Rochester, MN Post-Bulletin
Wall Street Journal
Friday, August 3, 2007
Thursday, August 2, 2007
Here is an FHWA Press Release dated Aug. 2, 2007:
Here is a security camera video of the collapse:
Here are photos of the collapse:
Diagramming the collapse:
Problems with Minnesota bridge noted twice since 2001:
Here is the MnDOT 2001 Report:
A 2001 study conducted by the Minnesota Department of Transportation found "several fatigue problems" in the bridge's approach spans and "poor fatigue details" on the main truss. The study suggested that the design of bridge's main truss could cause a collapse if one of two support planes were to become cracked, although it allowed that a collapse might not occur in that event. But, the study concluded, "fatigue cracking of the deck truss is not likely" and "replacement of the bridge ... may be deferred."
Two years ago, the U.S. Department of Transportation's National Bridge Inventory database said the bridge was "structurally deficient." The Minneapolis Star Tribune quoted Jeanne Aamodt, a spokeswoman for the Minnesota Department of Transportation, as saying the department was aware of the 2005 assessment of the bridge. The bridge received a rating of 4 on a scale of 1 to 10. A bridge receives a rating of 4 when there is "advanced section loss, deterioration."
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