Constructed in 1962, the Benicia-Martinez Bridge carries Route 680 traffic over the Carquinez Strait between the cities of Benicia in Solano County and Martinez in Contra Costa County. Currently, over 90,000 vehicles cross the bridge each day. When completed in 1962, the bridge was constructed to an initial 4-lane width of 67 feet. In 1991, the bridge was widened to its present width of 77 feet to accommodate six lanes of traffic.
SEISMIC RETROFIT STRATEGY:
In 1980, the bridge was seismically upgraded with earthquake restrainers and reinforced concrete support blocks. However, these upgrades have been determined to be inadequate for current seismic design goals. The current seismic design strategy is to ensure that the bridge will be serviceable and open to the general public after a Maximum Credible Earthquake(MCE).
The proposed retrofit strategy includes replacing the existing steel bearings with isolation bearings, adding a new tapered exterior concrete jacket to most of the piers and adding additional caissons with tie down anchors. Other work proposes to strengthen the approach columns and widen the column footings, place larger expansion joints at the abutments and strengthen the steel members which comprise the truss structure.