The U.S. Government Accountability Office says the U.S. has 23,357 fewer deficient bridges than it did a decade ago, but there’s still a long way to go to repair or replace the more than 151,000 that are still on the deficient list.
The GAO updated its report on deficient bridges in the U.S. following the May 23 collapse of an Interstate 5 bridge in Washington state.
“There has been limited improvement in bridge conditions in the past decade, but a substantial number of bridges remain in poor condition,” the GAO stated in the report’s opening sentence.
Report authors said the collapse of the I-5 bridge north of Seattle last month “underscores the importance of maintaining the nation’s infrastructure and the economic impact that a bridge failure can have on a region.”
The bridge that collapsed carried 71,000 vehicles per day, including more than 6,000 trucks.
The GAO says U.S. bridge inventory totaled 607,380 in 2012, and that about one in four, or about 151,497, were considered deficient. The deficiency number combines bridges listed as “structurally deficient” with those listed as “functionally obsolete.”
Ten years prior, when the bridge inventory totaled 591,243, the number of deficient bridges totaled 174,854 – a ratio of about one in 3.4.
The I-5 bridge over the Skagit River was considered functionally obsolete, but also had an engineering designation of being “fracture critical,” meaning it was one incident – such as an earthquake or being struck by a heavy truck – away from a possible collapse.
In the early evening of May 23, a permitted truck hauling an oversized load struck bridge supports seconds before a 160-foot section plunged into the river. No one was killed in the collapse, but rescuers pulled three people in passenger vehicles from the water.
The National Transportation Safety Board’s investigation into the collapse continues.
The GAO made no new recommendations in its latest report. Instead, it urged continued follow-through with performance-based provisions in the 2012 highway law MAP-21, Moving Ahead for Progress in the 21st Century.
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