Owner: State of California
Contract value: $3,908,000
This seismic rehabilitation work involved the complete replacement of an existing seismic joint of the San Mateo Bridge, consisting of two 32-ft long bridge spans with steel cover plates. The work location bridged the main channel high rise structure and the trestle section of the Bridge, approximately two miles from the Foster City abutment. The specific retrofit work included the strengthening of existing steel and concrete bearing surfaces, the jacking and temporary supporting of existing concrete bridge girders under live traffic, and the demolition and replacement of existing girders and seismic joint plates under complete closure of the bridge. The new seismic joint is comprised of 12 separate precast, prestressed girders erected in an overlapping configuration to create a 3-ft seismic gap.
The contract originally allowed for two separate complete 55-hour weekend closures of the Bridge to replace the deck girders and complete the seismic joint. Shimmick and Caltrans partnered to develop and successfully execute a plan to complete the project with a single complete closure.
Other work included removal and reinstallation of electrical conductors that pass through the seismic gap, installing permanent access structures, and installing changeable message signs above the roadway.