Dumbarton Bridge Seismic Retrofit, Newark
This seismic retrofit was completed ahead of schedule and at a cost savings for Caltrans. The bridge carries more than 64,000 vehicles daily between Alameda and San Mateo County. The contractor's scope included creating bridge-supported access platforms, which eliminated costly marine support from work at 16 pier caps. The platforms served as falsework to support the concrete, which was pumped over the road deck edge during nightly lane closures. Crews raised the bridge 5 in., using 300-ton and 400-ton jacks to allow installation of the steel seismic isolation bearings, which weighed 15,000 lb each. After hoisting the bearings from the bridge deck onto a trolley, the team installed them between pier caps and existing bridge steel box girders in spaces as tight as 15 in.
Contractor Shimmick Construction Co., Oakland
Owner Caltrans, District 4, Oakland
Lead Design Caltrans, District 4, Oakland
Subcontractors: Jeffco Painting & Coating, Vallejo; CMC Rebar, East Stockton; Myers & Sons Construction, Sacramento; Penhall Co., Santa Clara; Bay Cities Grading & Paving, Concord