Tunnels
Airport Boulevard On-Ramp Undercrossing (VECP)This project consists of the value engineering review and fast-track redesign of over 1,000 feet of cut and cover tunnel and depressed roadway at Route 880. Based upon our value engineering review of the contract plans for the Contractor it was determined that it would be more economical to construct the structure with the use of cement deep soil mix (CDSM) walls and cast-in-place reinforced concrete U-walls. We also coordinated the Value Engineering Cost Proposal approval from Caltrans, the VTA and peer review by the original design consultant, as well as the design with several construction disciplines including CDSM, waterproofing and tieback consultants.
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Diridon Subway ProjectBiggs Cardosa was the prime consultant for the structural design for all major structural elements along the five-mile extension of the Santa Clara Valley Transportation Authority’s light rail system, from the City of San Jose into downtown San Jose. One of the structures designed under our contract was the Diridon Subway. The subway extends underneath 12 railroad tracks, the multi-modal transit facility, and State Highway 82, requiring coordination with the JPB/Caltrain, Amtrak, UPRR, Caltrans and City of San Jose. The main subway section is approximately 250 meters (800 feet) long and consists of a cast-in-place concrete, cut and cover, double-cell box.
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SFMTA Tunnels and Underground StationsThe San Francisco Municipal Transportation Agency (SFMTA) is one of the oldest public transit agencies in the country and has operated for 100 years. It now operates buses, light rail vehicles and cables cars on 80 routes throughout the City. SFMTA owns and operates two tunnels (Twin Peaks Tunnel and Sunset Tunnel) that include two underground stations (Eureka Valley Station and Forest Hill Station). These structures were built between 1910 and 1930 and have had little modification since that time. As lead structural engineer for the prime consultant, Biggs Cardosa led a team of engineers and sub-consultants to prepare a seismic evaluation of these structures. The BART Earthquake Safety Program Evaluation Criteria were used, consistent with evaluations that have been completed for BART underground structures that are jointly operated with SFMTA.
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