TYLin provided design and construction phase services for the New Benicia-Martinez Bridge in Benicia, California.
A signature bridge for the communities of Benicia and Martinez, the 7,400-foot-long bridge is part of the California Lifeline Route System, a system in which all bridges are to be open to traffic shortly after a seismic event.
TYLin performed a preliminary design study and prepared cost estimates for the concrete box girder alternative. The California Department of Transportation (Caltrans) then retained the firm, as part of a joint venture, to complete the final design and prepare plans and construction estimates for the segmental concrete girder alternative.
The New Benicia-Martinez Bridge has 22 spans, 12 over water. The five-lane toll bridge is over 83 feet wide and aligned east of and parallel to the existing six-lane Benicia-Martinez Bridge and Union Pacific Railroad Bridge.
The post-tensioned, concrete box girder was primarily constructed using the balanced segmental cast-in-place construction method, a challenge at the time for such long spans (up to 659 feet in length). The segments are 15.8 feet long, with a maximum of 19 segments cantilevered from each side of the fixed moment-connection pier.
Significant features of the New Benicia-Martinez Bridge include two moment-resisting midspan hinges between the three-span continuous frames, a unique application at the time for a high-seismic zone. These elements provide continuity for post-construction loads (live loading and force redistribution). They also lock the cantilevers laterally and vertically together to minimize temperature displacement and movements from a seismic event.
- TYLin’s design represented the first Caltrans segmental bridge to in 20 years.
- The bridge was designed and constructed to lifeline seismic standards.
- To reduce foundation costs, the deep-water foundations use large-diameter steel shell caissons.
- Sand-lightweight concrete was used for the superstructure to reduce seismic forces.
- The bridge carries facilities for Bay Area Rapid Transit.