“It’s too soon to know what caused the Minnesota bridge to fail,” said Pamela Lowe, Director of the Idaho Transportation Department. “Our bridge inspectors and engineers, like their counterparts across the country, are anxious to learn what caused the collapse. But in the meantime, Idaho motorists are safe on our bridges.”
Idaho has 1,761 bridges on its state highway system. A veteran crew of professional bridge inspectors and bridge engineers inspects each bridge at least every two years – or more often, if necessary. The inspectors use special equipment that allows them to view the bridge from all angles. ITD also uses a trained dive team to conduct underwater inspections of piers and pilings.
As a result of the Minnesota collapse, the term “structurally deficient” bridge has entered the common vocabulary of Americans. The term does not mean that a bridge is unsafe. Ninety-five bridges on the state highway system are included in this federal engineering classification.
Structurally deficient means that a bridge is no longer in an ideal condition. Bridges nationwide are classified as structurally deficient based on conditions such as deck and girder conditions. Bridges rated structurally deficient are inspected annually by the transportation department.
To qualify for Federal Highway Bridge Program funds for replacement or rehabilitation, a bridge must be rated structurally deficient.
“We are confident about the safety of our bridges because of our frequent inspections and appropriate maintenance,” Lowe said. “Yet we acknowledge that Idaho, like most other states, has a growing concern as our bridges age. By 2017, more than half of our bridges will be at least 50 years old. Like much of the nation, many of those structures were built during the interstate construction era.”
“We will need to dedicate more money to maintain and replace our aging bridges,” Lowe added. “That will be a challenge on both a national and state level.”
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