Collapse improves state bridge policyTransportation experts say states reviewed bridge policies after the Interstate 35W bridge collapse, but wonder if the issue will be a national priority long after this week’s findings from a collapse investigation.
By: Scott Wente, Worthington Daily Globe
ST. PAUL — Transportation experts say states reviewed bridge policies after the Interstate 35W bridge collapse, but wonder if the issue will be a national priority long after this week’s findings from a collapse investigation.
Minnesota officials, a bridge expert studying the collapse and transportation-minded lawmakers said the state has improved its bridge inspections and understanding of bridge design and safety following the Aug. 1, 2007, Minneapolis collapse.
It is too soon, however, to know whether the collapse and the National Transportation Safety Board’s probe into the cause will lead to continued attention to bridge safety.
“Overall, our bridge department’s going to come out of this in a much stronger position,” said Steve Murphy, a Red Wing Democrat and chairman of the state Senate Transportation Committee that has monitored post-collapse bridge developments. “My only worry is that other departments across the United States are not making the same effort to update their bridge programs and the way they go about acquiring evidence through their inspection process.”
The NTSB today concludes a two-day hearing of its year-long Interstate 35W bridge investigation.
The bridge collapse started at an area of inferior steel elements known as gusset plates, federal transportation investigators said Thursday, faulting the original design of a critical element of the bridge that fell into the Mississippi River.
“This terrible tragedy began some 40 years ago with an inadequate design of a gusset plate or, in this case, a number of gusset plates,” NTSB Chairman Mark Rosenker said of the collapse that resulted in 13 deaths and injuries to more than 140.
Investigators focused their report Thursday on gusset plates half as thick as they should have been and the effect of extra weight from construction materials and equipment on the bridge deck the day of the collapse. They said their investigation ruled out several other theories behind the collapse, including corroded bridge components.
Even before the NTSB released its findings, local transportation officials said the collapse and subsequent investigation changed bridge safety in Minnesota.
State Bridge Engineer Dan Dorgan, who was in Washington for the NTSB report, told state lawmakers Wednesday Minnesota led states earlier this year in reviewing gusset plates on similarly designed bridges. NTSB officials sought the review in January after announcing gusset plates were a focus of their investigation.
Dorgan, Minnesota Department of Transportation’s top bridge official, said state officials also have shared lessons they learned from the collapse with their counterparts across the country.
Gov. Tim Pawlenty, a Republican who blamed some Democrats for jumping to conclusions about the cause of the bridge collapse, said the NTSB results “underscore why it was important to withhold judgment until the investigation was complete.”
The collapse led to renewed attention to sophisticated engineering techniques used in recent bridge construction, a University of Minnesota professor said.
The collapse prompted state transportation agencies to take a closer look at similarly designed bridges in their states, and there may be a greater use of equipment built into a bridge that constantly assesses the structure’s condition, said Roberto Ballarini, who leads the university’s civil engineering department.
Ballarini said civil engineering theories develop slowly, so not much has changed in the 15 months since the collapse. However, he said, it likely will prompt more research into bridge design.
“As time progresses, there probably will be a lot more modeling of the structures on the computer to predict their behavior,” said Ballarini, who with university faculty and students is completing a separate investigation into the bridge collapse. He described it as a small-scale version of the NTSB investigation.
The NTSB findings come months before Congress starts writing new legislation that will guide federal highway and bridge funding.
U.S. Rep. Jim Oberstar, who leads the House Transportation and Infrastructure Committee, refused to discuss Thursday either the NTSB report or the impact of the collapse on bridge safety before the federal panel concluded its two-day hearing. Oberstar’s spokesman said the congressman would comment today at the conclusion of the two-day hearing, when the NTSB releases its summary report.
Oberstar’s opinion on the bridge collapse and investigation is significant given that he is expected to lead the committee next year that will draft new transportation policy. Further, he has criticized the NTSB for a leak to the media about its investigation and has been skeptical of its focus.
Wente works for Forum Communications Co., which owns the Daily Globe.