Report issued on Minneapolis bridge problemPublished 10:02am Sunday, July 1, 2012
MINNEAPOLIS — A final report recommends installing a system on a Minneapolis bike and pedestrian bridge to reduce the wind-induced cable vibrations that caused a pair of cables to fall in February.
The engineering firm Wiss, Janney, Elstner Associates also found that in addition to the vibrations, several other factors also contributed to cracking two steel plates that fasten cables to the Sabo Bridge, including misalignments and extreme temperature changes.
The five-year-old bridge is supported by 18 pairs of metal cables and was designed by URS Corp. of San Francisco.
According to the 140-page report released Friday, URS considered cable vibrations in the design, but waited until the bridge was built before deciding a damping system wasn’t needed.
URS issued a statement saying it will conduct a comprehensive review of the findings.