DES MOINES, Iowa — A decade after a deadly freeway bridge collapse in Minneapolis, a study has found that thousands of Iowa’s bridges are deemed structurally deficient.

The 2007 Minneapolis bridge collapse that killed 13 people and injured 135 sparked concerns about deteriorating infrastructure around the U.S.

A study the American Road & Transportation Builders Association released in February found that nearly 5,000 of Iowa’s more than 24,000 bridges are rated as structurally deficient, The Des Moines Register reported . That means one of the bridge’s key elements — such as the deck, superstructure or substructure— is in poor or worse condition.

Most of those bridges are in rural areas and farming communities that see relatively low traffic.

Iowa County Engineers Association spokesman Lyle Brehm, who is also an engineer in Tama and Powershiek counties, said motorists don’t need to be concerned.

“We are required by federal statute to inspect every 24 months and we monitor the deterioration of them,” Brehm said.

Bridges are closed for repairs if there’s a serious problem, he said.

State Department of Transportation officials said the agency has reduced the number of structurally deficient bridges on state and interstate highways from more than 250 in 2006 to just over 60 in 2016. The department oversees less than 10 percent of the state’s overall road system, but its roads handle more than 60 percent of the state’s traffic.

State officials said a 10-cent-per-gallon state fuel tax increase enacted in 2015 will help fund further improvements. The tax generates about $200 million annually for road and bridge projects in the state.

“A lot of interstate bridges were constructed in the 1960s, and a lot of those will be coming up for replacement in the next 10 years or so,” said Norm McDonald, director of the department’s bridges and structures office. “So there will be a huge investment there.”


Information from: The Des Moines Register, http://www.desmoinesregister.com