Award of Merit: Highway/Bridge: Broadway Bridge Rall Wheel Replacement
Broadway Bridge Rall Wheel Replacement
Award of Merit
Owner: Multnomah County Bridge Services
General Contractor: Hamilton Construction
Lead Designer: Hardesty & Hanover
Structural Engineer: OBEC Consulting Engineers
Broadway Bridge is a Rall-wheel, double-leaf drawbridge that has carried pedestrians, trucks, cars and street cars across Portland’s Willamette River since 1913. With the longest span of any bascule bridge in the world, it’s also listed on the National Register of Historic Places. But after 104 years, the worn, 8-ft-dia wheels and tracks that support the bridge needed to be replaced.
The cast-steel wheels, which each weigh nearly 56,000 lb, were replaced with a stronger forged-steel design that weighs 88,000 lb. A temporary shoring and jacking system was used to support the more than 2-million-lb wheel loads so they could be removed and replaced.
During the project’s testing phase, rivets sheared off due to friction between the new track and the truss. The project team used a large barge crane to remove the old components and a steel saw to cut away a small portion of the track edge, allowing the bridge to open and close freely.