The 2.4km tied-arch bridge, which was built in 1980, carries the I-43 highway.
A large dip in the span was reported by motorists and a bridge inspector from Wisconsin Department of Transportation (WisDOT) arrived on scene shortly afterwards. The 122m-span was sagging across all four lanes of the structure. Initial reports by bridge inspectors indicated that ‘pier 22’ on the east side of the bridge over land settled, leading to the sagging. Visual ground observations also show settlement.
Regional, federal and state bridge engineers are investigating the structure to determine the extent of the problem. This team includes structural and geotechnical engineers from WisDOT and the Federal Highway Administration. Representatives from Michael Baker, Jr and Wiss, Janney, Elstner Associates have also been added to the team.
"We need to make sure everyone is safe out there before we do anything around pier 22, either below or above," said WisDOT north east region director Will Dorsey. "Once the safety measures are in place, then we can go in and start collecting soil samples, taking readings on the piers themselves, and using laser and visual inspections. In addition to our on-site investigation, we are also reviewing historical engineering and site data to help understand all aspects of this event."
A repair of the substructure was completed in 1988. The bridge was last inspected August 2012 and was not on the list of 60 deficient bridges in the state. It underwent asphalt, joint and pin replacement in 2012 and 2013.
