Feds point to poorly designed gusset plates as cause of bridge collapse
1/15/2008 10:09:44 PM
By Frederic J. Fromme
WASHINGTON -- Undersized gusset plates in the Interstate 35-W bridge in Minneapolis were "the critical factor" in the bridge collapse last year that killed 13 people and injured 100, the National Transportation Safety Board said Tuesday.
Chairman Mark Rosenker said the plates, which connected steel beams, were roughly half the thickness they should have been because of a design error. Investigators found 16 fractured gusset plates from the bridge's center span, he said.
"It is the undersizing of the design which we believe is the critical factor here. It is the critical factor that began the process of this collapse. That's what failed," Rosenker said.
The Minneapolis bridge was a steel-deck truss bridge that opened in 1967. Rosenker said it wasn't clear how the design flaw made it into the bridge because investigators couldn't find the design calculations.
Once they made it into the completed bridge, he said, there was little chance they would be noticed by inspectors.
"The NTSB investigation is not yet complete, but the focus of the investigation appears headed in a direction different than many of the political claims that have been made here in Minnesota. It is our hope that at least now people will reserve further judgment until the investigation is complete and that we strive to address these matters in a fair, factual and nonpolitical manner." -- Minnesota Gov. Tim Pawlenty.
"From the day after the collapse, from those of us involved in the industry the most important thing has been to determine the cause. ... There might be a small measure of relief at this time for those in the industry to know that we are now seeing the beginnings of the cause." -- Dan Dorgan, state bridge engineer.
"The work of the NTSB shows further that last summer's knee-jerk reaction to increase the gas tax and create another duplicative federal program before knowing what caused the collapse made no sense." -- U.S. Rep. John L. Mica, (R-FL), the top Republican on the House Transportation and Infrastructure Committee.
"As the governor has said, the NTSB investigation is not yet complete. It would be helpful if he would follow his own advice and not add his own speculation on the cause of the 35W bridge collapse. ... (W)e told Minnesotans we will work to restore their faith in our roads and bridges. That includes finding not only the cause of the bridge collapse, but also reviewing decisions made by leadership at the Minnesota Department of Transportation. Finally, the most important step we can take is passage of a bi-partisan, comprehensive transportation funding plan that serves all of Minnesota." -- House Speaker Margaret Anderson Kelliher (DFL-MN)
"The collapse of the I-35W bridge should be a call to action. When over 12 percent of all American bridges are in need of serious repair and the Highway Trust Fund is projected to go into deficit in (fiscal year 2009) -- it's clear additional investments in our state and national infrastructure must be made." -- U.S. Sen. Amy Klobuchar (D-MN)
"These findings are helpful, but they do not make Minnesotans feel any safer as they travel with their families across our bridges. An improved NTSB inspection process on both the state and federal levels, as well as a commitment by all our elected officials -- including those running for president -- to fully fund our infrastructure needs would restore the public's faith in our roads and bridges." -- U.S. Rep. Keith Ellison (D-MN)
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