Work begins to repair Sabo Bridge

Repair work will begin next week on the Sabo bike and pedestrian bridge, where support cables broke loose last winter. In this phase, engineers will install one retrofitted diaphragm plate on the bridge, which crosses over Hiawatha Avenue in south Minneapolis. The repair to the plate will then be monitored over the next month to see how it performs. Engineers will then plan and schedule repairs to the rest of the bridge’s diaphragm plates later this year.

One of the bridge’s diaphragm plates fractured in February, causing a pair of suspension cables to break loose.Wiss, Janney, Elstner Associates, Inc., an engineering firm hired to find the cause of the fracture, concluded in June that wind-induced cable vibrations caused fatigue cracking in the diaphragm plates resulting in two cable connections fracturing. The retrofitted plate being installed this weekend is designed to withstand the fatigue that caused the cracking. 

The retrofitted diaphragm plate will connect to one pair of cables on the Sabo Bridge. This particular pair is the third longest set of cables in the bridge design, and they are the longest cables currently attached to the bridge pylon. Crews will need to de-tension that cable group before the retrofitted plate can be installed. 

In order to conduct this repair work, the bridge will close to bike and pedestrian traffic beginning at 7 a.m. Sunday, Aug. 19. During the closure, which will last approximately one week, bike and pedestrian traffic will be detoured to the intersection of 28th Street and Hiawatha Avenue.

Also as part of this work, both directions of Hiawatha Avenue between East 26th Street and East 28th Street will close to traffic starting at 7 a.m. Sunday, Aug. 19. The highway is scheduled to reopen by 5 a.m. Monday, however it is likely that it will open earlier, once work is complete. Drivers will need to follow the posted detour routes.

This phase of the repair is expected to be completed later in the week, and at that point, Hiawatha Avenue will need to close again for a short time. More details on a possible second closure will be available as the work progresses.

The Sabo Bridge is a 215 foot-long cable-stayed suspension bridge that opened in November of 2007 to carry Midtown Greenway bicycles and pedestrians over Hiawatha Avenue. The bridge was built by Hennepin County and turned over to the City of Minneapolis when construction was completed.

Published Aug 16, 2012