Research released Friday by NBC’s Today Show found that Oregon has the fourth-highest number of bridges built in the "truss" style that collapsed Wednesday in Minneapolis.

According to a report released by the Oregon Department of Transportation, Oregon has 28 steel deck truss bridges in the state. Six of those bridges were rated structurally deficient and eight were found functionally obsolete.

View : ODOT report (pdf)

Details : 756 'truss' bridges in U.S.

The tragic bridge collapse in Minnesota raises questions and concerns about the safety and stability of major bridges everywhere, including Portland.

According to the American Society of Civil Engineers, 25 percent of Oregon's bridges are structurally deficient or functionally obsolete.

Within the Portland Metro area, there are 15 bridges and experts believe the Sellwood Bridge, which crosses the Willamette River on the south end of town, is most at risk for problems. A weight restriction was implemented as a precaution after cracks appeared in concrete girders in 2004; vehicles weighing over 10 tons are now restricted from crossing the Sellwood Bridge.

Poll: Worried about bridges in Oregon and Washington?

Comment: Outraged over bridges in need of repairs?

A project to replace or repair the structure of the Sellwood Bridge is in the works, but until that happens, Multnomah County officials placed weight restrictions to prevent any collapse.

Sellwood Bridge: proposed options

Vote on Sellwood Bridge options

“Portland being a city that has lots of bridges, we have to make sure that we are vigilant about keeping those bridges up-to-date and maintained well, so that something like this never occurs,” said University of Portland engineer Mark Kennedy.

 Background: County proposes changes to Sellwood Bridge

Kennedy also pointed out that it is rare to see the type of bridge collapse that happened in Minneapolis on Wednesday.

ODOT study analyzed bridges statewide

However, a 2003 report from the Oregon Department of Transportation warned that the deterioration of Oregon bridges has accelerated over recent years. It said that in 2000, Oregon had 35 bridges that were under evaluation and 13 of them required emergency repairs. In 2001, ODOT put 555 bridges under evaluation for cracking and 18 had emergency repairs.

The report concluded that by 2010, ODOT expected they would need to implement weight restrictions on 30 percent of state bridges as a precaution related to structure concerns.

In Washington state, there are more than 3000 bridges and engineers with the Washington State Department Transportation visually inspect each structure at least once every two years. Although, WSDOT engineers say they would like to conduct inspections more often.

Major bridge repair project underway

Oregon is undergoing a $1.3 billion, 10-year state-funded project to fix 365 bridges found most in need of repair. More money is earmarked to check city and county owned bridges.

Details : Full repairs would cost $4.7 billion

Bridge concerns nationwide

Nationwide, the American Society of Civil Engineers reports that more than 27 percent of America's bridges were structurally deficient or functionally obsolete when a study was conducted in 2003.

"While not necessarily unsafe, these bridges must have limits for speed and weight," the study found. "A functionally obsolete bridge has older design features and, while it is not unsafe for all vehicles, it cannot safely accomodate current traffic volumes and vehicle sizes and weights."

Specific recommendations from the ASCE called for setting a national goal that fewer than 15 percent of America's bridges be classified as structurally deficient or functionally obsolete by 2010 and improved federal funding for repairs and rebuilding.