Bicyclists and pedestrians who travel over the Sabo bridge in Minneapolis will have to take some detours this fall.
Starting this week, the steel plates that hold the cables to the 100-ft tall steel pylons will be reinforced.
In February, two of the 3/4-inch plates broke -- one fractured completely, causing a pair of cables to fall off the bridge. A study of the damage determined that the plates were stressed by vibrating cables. Hennepin County engineer Dean Michalko says county officials are exploring whether they need to install a dampening system to reduce vibrations.
"We're actually hiring some experts to analyze that for us and tell us what their recommendations would be as far as whether or not dampening is something that is beneficial," he said.
Minneapolis city officials say the bridge will be closed until repairs are completed in December.
The Hennepin County Board recently approved a contract paying Wiss, Janney Elstner Associates $750,000 to conduct the bridge retrofit. However, Michalko says the county and the city of Minneapolis may seek reimbursement from the San Francisco-based firm URS, who designed the bridge.
According to a report assessing the damage, WJE investigators said URS engineers determined that cable vibrations, "didn't appear to be an issue." A spokesperson for URS said they were interested in "factors that did not involve our company," such as the misalignment of some of the plates.