State Officials Looking At Their Own Bridges After Collapse

By Sarah Goebel | 

In the wake of the Aug. 1 bridge collapse in Minnesota, state officials throughout the country are taking a closer look at their bridges .

Governors are scrambling to conduct inspections after the collapse.

The Interstate 35-W bridge over the Mississippi River was jammed with traffic when it fell.

Authorities say at least four people were killed and about 60 were injured.

The eight-lane bridge was being repaired and had several lanes closed when it crumbled.

So far, officials don't suspect anything other than structural failure.

The Ky. Transportation Dept. says there are 14,000 bridges in Kentucky and about 800 of them are in our area.

Though the bridges in South-Central Ky. are smaller than the one in Minnesota, we did find one that's similar.

Shane Palmquist was a bridge inspector for more than five-years and now teaches Civil Engineering at Western Kentucky University.

"I've never seen anything like this. I would consider that bridge to be in the early stages of middle age," Palmquist said.

The bridge in Minnesota is only about 40-years-old, but Palmquist said there are several reasons why a bridge like that would collapse.

"The piers being knocked by a boat that was in the water, or a blast if it was a terrorist, issues during construction, or even if a car damaged it," he explained.

The type of bridge can also play a part in what happens to it if the bridge is damaged.

"That bridge is a truss-type bridge. It's actually a curve-arch truss bridge. College Street Bridge is also a truss bridge. If a primary member or a major connection fails, there's a significant possibility that that force can not redistribute to other members," Palmquist added.

That can cause the entire bridge to collapse instead of just the damaged portion.

Palmquist said that might be what happened in Minnesota, but he said bridges are checked regularly so there is no need to worry about safety.

"Those bridges are inspected every two years, sometimes more if it's a truss bridge that has weight restrictions," said Keirsten Jaggers, Kentucky Transportation Dept. Spokeswoman.

Jaggers said anytime a bridge is damaged, it's thoroughly inspected and repaired and there are federal guidelines every state has to follow to ensure bridges don't collapse.

Palmquist said he'll be taking his students to the College Street Bridge to climb it and learn how truss bridges like the one Minnesota are built.

You can find much more information on how bridges work, what resonance is and how technically the bridge collapse happened, here.

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