Bridge inspectors have begun to recheck the design of 23 trunk highway bridges - bridges found in Dakota, Chisago, Sherburne counties and elsewhere - in a screening given impetus by a federal preliminary finding on the collapse of the I-35W bridge.

State bridge engineer Dan Dorgan spoke at a press conference and reflected on speculation about weaknesses in bridge construction. The National Transportation and Safety Board had earlier given their preliminary report on the I-35W bridge collapse. (Photo by T.W. Budig, ECM Capitol Reporter)

by T.W. Budig
ECM capitol reporter

Bridge inspectors have begun to recheck the design of 23 trunk highway bridges - bridges found in Dakota, Chisago, Sherburne counties and elsewhere - in a screening given impetus by a federal preliminary finding on the collapse of the I-35W bridge.

Gov. Tim Pawlenty (pictured at right) on Tuesday (Jan. 15) ordered the Minnesota Department of Transportation (MnDOT) to under go the design checks following a preliminary report by National Transportation Safety Board (NTSB) indicating that a design flaw relating to the thickness of steel gusset plating used on the I-35W bridge could have resulted in its collapse last August killing 13 people.

The safety board opined that some of the critical steel plates on the I-35W bridge were designed too thin.

According to Mn/DOT officials, the department began reviewing the designs of gusset plates on similar truss-style bridges in the state last August after NTSB officials first raised concerns about weight loads and gusset plates.

Design checks by June

All 23 trunk highway bridges are scheduled to have their design checks by June.

Mn/DOT officials expect the check of the Highway 61 bridge at Hastings to be completed by April.

It has completed checking the gussets - connectors designed to be stronger than the beams they hold - on the Highway 23 bridge in St. Cloud..

Additionally, Mn/DOT has completed a check of the most heavily loaded gussets on the Highway 243 bridge over the St. Croix River near Osceola and on the Highway 123 bridge over the Kettle River near Sandstone.

According to the department, no problems have been found by the computer modeling to check all the gusset connections on the bridges.

State bridge engineer Dan Dorgan opined that had I-35W bridge undergone the same design re-evaluation as scheduled for the other similar bridges in the state, engineers would have discovered its possible fatal design flaw.. "With what we're understanding at this moment, yes," he said

State bridges safe, Dorgan says

Minnesota bridges are safe, insisted Dorgan, and motorist should not be nervous crossing them. "No they should not," he said, speaking at an afternoon press conference.

Although the same firm, Sverdrup and Parcel of St. Louis, designed both the I-35W bridge and the Hastings bridge, Dorgan explained that the two bridges are very different.

In addition to the 23 trunk highway bridges, Mn/DOT hopes to work with local government to reexamine the designs of 36 truss-style bridges on local road systems.

All told, 59 truss-style bridges are hoped to be checked.

Mn/DOT is hiring additional consultants to help check the gussets on the 23 state highway bridges with high-truss designs.

Checking the 23 bridges is expected to cost $500,000, according to the Pawlenty Administration.

Pawlenty, Mn/DOT officials, on Tuesday afternoon urged the public to withhold judgment or blame relating to the I-35W bridge collapse.

Final report not yet issued

The NTSB has not yet issued its final report, he noted. "Some individuals have leapt to premature conclusions," said Pawlenty.

Indeed, the governor charged that the tragedy has been exploited to advance political agendas.

Pawlenty said he hoped to find "common ground" on the issue of transportation funding.

House Speaker Margaret Anderson Kelliher, DFL-Minneapolis, said there was much still to learn from the bridge collapse. "As the governor has said, the NTSB investigation is not yet complete," Kelliher in a press release.

"It would be helpful if he would follow his own advice and not add his own speculation on the cause of the I-35W bridge collapse," she said.

Sen. Murphy offers criticism

Senate Transportation Committee Chairman Steve Murphy, DFL-Redwing, at a morning press conference prior to the NTSB findings criticized Pawlenty's recent proposal to bond for $225 million in bridge funding.

That's political gesture, he explained.

"Governor Roadblock needs to get out of the way," said Murphy.

Murphy, who along with Sen. Katie Sieben, DFL-Newport, expressed concern over the condition of the Highway 61 at Hastings, Murphy opining weight limits on the bridge should be lowered.

Some of the local truss bridges MnDOT officials want checked include: