Oklahoma closes two bridges, decrease weight limit on 25 others

A bridge over State Highway 74 over the Washita River in Garvin County reopened Friday after modifications were made.

The Trucker News Services

6/29/2010

OKLAHOMA CITY  — The Oklahoma Department of Transportation temporarily closed two bridges and decreased the weight limit on 25 others after reviewing their design to ensure they conform with new safety standards put in place after the deadly 2007 Minnesota bridge collapse.

The review began with 30 bridges, Gary Evans, chief engineer at the state Department of Transportation, said. Six bridges have weight limits of less than 15 tons — the weight of a fully loaded school bus, Evans said.

"We're not saying they are unsafe," Evans said. "If we had a bridge that was unsafe we would close it until we could ensure it was safe for travel."

The weight limit on the bridges is decreased to prevent additional damage to the bridges, he said.

"It does not mean if a large vehicle crosses the bridge that it's going to collapse," Evans said. "It may, however, cause further damage."

A bridge over State Highway 74 over the Washita River in Garvin County reopened Friday after modifications were made. A bridge on SH 109 over the Kiamichi River in Choctaw County opened to traffic on Saturday after modifications were made.

The bridges under review were built from 1924 to 1965 and have a similar design to the Interstate 35 bridge in Minnesota that collapsed in 2007 killing 13. The bridges have a truss system to help support them as they span long distances, such as over a river, Evans said.

After studying the bridge collapse, the Federal Highway Administration issued new safety standards for truss bridges. In the Minnesota collapse, plates connecting the bridge's girders partially failed.

In Oklahoma, engineers working with the state Department of Transportation are reviewing the blueprints of the bridges and making adjustments to fortify the bridges based on findings in the Minnesota collapse.

"It's not unusual to have to make modifications to bridges," Evans said. "These modifications are not substantial or costly."

The cost of the repairs is included in the department's budget and could be finished in the next few months, Evans said.

In Oklahoma, some 1,400 bridges cannot support the weight they were designed to carry, Evans said. There are about 6,700 bridges in the state.

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