A recent study revealed that the state of Iowa has the fourth highest number of structurally deficient bridges in the nation.

According to the report by TRIP, a Washington, D.C.-based transportation research group, 5,153 of Iowa’s bridges, or 21 percent, are close to being unsafe for usage. Additionally, 1,455, or 6 percent, were rated as “functionally obsolete,” meaning that they did not meet current safety standards.

One bridge in Ames, the Main Street overpass crossing over Grand Avenue, was ranked the 72nd most structurally deficient bridge in the state.

Iowa Department of Transportation Director Nancy Richardson responded to the study in a news release.

“The report is a fair assessment of the condition of Iowa’s aging infrastructure,” she said in the release. “But as the report suggests, the federal rating system and terms like ‘structurally deficient’ and ‘functionally obsolete’ do not mean the bridges are unsafe. They are simply classifications under the federal bridge funding program.

“Any bridge in the state found to be unsafe would be immediately closed. Iowans should feel confident in the safety of our bridges,” she said.

The Iowa DOT reports that 20 to 30 bridges become deficient each year. With the proposed funding for 2008, fewer than 15 will undergo proper reconstruction.

Every two years, the Iowa DOT is required to inspect the 24,776 bridges in Iowa that are more than 20 feet long and the money needed to cover their efforts is around $257 million. This figure will not be met under current funding conditions and state government officials are working to address the situation.

Sen. Tom Rielly, a Democrat from Oskaloosa, is the chairman the Iowa Senate Transportation Committee and commented on the TRIP study.

“I am very confident that we are going to get something done this year,” he said. “These are very, very serious issues as they relate to roads and bridges.”

The plan to increase funding for bridge reconstruction includes the possibility of raising fees to register new cars and trucks as well as increasing the fee for driver’s license renewal.

Gov. Chet Culver has reportedly ruled out the possibility of raising Iowa’s gasoline tax, but the possibility of raising other fees is currently undergoing discussion.

Most concerning to the community is the safety of roads driven by people on a daily basis. The TRIP report defined “structurally deficient” as deterioration of a bridge deck and poor superstructure and substructure ratings. Using a scale of 0 (failed condition) to 9 (excellent condition), the TRIP study rated Iowa bridges. Only 622 of them reached a rating of 5.

The cost of materials needed for bridge construction, such as asphalt, steel and diesel fuel, has increased by 43 percent, the Iowa DOT reported. This increase contributes to the lack of monetary resources available to update bridge repairs. To raise awareness and encourage fundraising for bridge reconstruction, Iowa State provides knowledge and labor to bridge research and roadway infrastructure projects.

The Center of Transportation and Research Education at Iowa State is involved in bridge evaluation and testing. Jake Bigelow, a bridge research specialist at CTRE, stressed the importance of testing bridge load capacity.

“It’s important to determine the safety and functional capacity of bridges, and we specifically look at how it deflects or moves,” he said. “We use certain weight tests with loaded dump trucks to determine how the bridge is suited for stress and its load capacity.”