BART Silicon Valley Extension Phase 2, BSV II – Single Bore Tunnel Project, San Jose, CA

Santa Clara Valley Transit Authority (VTA)

AVA’s Role: Anil Verma Associates, Inc. (AVA) serves as Design Architect for the Downtown San Jose Station; two tunnel portals, one at each end of the single-bore tunnel; two mid-tunnel ventilation structures; and their associated ancillary facilities. One ventilation structure is located near Santa Clara Street and 13th Street, and the second is located near the Santa Clara Caltrain rail yard. The BART Silicon Valley Extension Phase II (BSV II) includes a six-mile single-bore tunnel alignment extending from 28th Street/Santa Clara Street to the Caltrain rail yard and is one of the world’s longest rail tunnel projects. AVA’s responsibilities include configuration of the underground station and ancillary equipment spaces, as well as conceptual design, preliminary engineering, and final design for the two portals and two mid-tunnel ventilation structures.

BSV II – Single Bore Tunnel Project

Downtown San Jose Station: Downtown San Jose Station is a deep underground station located beneath Santa Clara Street in the heart of the city’s commercial core. The station platform and concourse are located within the single-bore tunnel. The station extends from Market Street east to a point between Second and Third Streets and includes a 700-foot-long center-boarding platform. The primary entrance shaft is located within the VTA-owned “Mitchell Block,” bounded by First Street to the east, Market Street to the west, East St. John Street to the north, and Santa Clara Street to the south. This shaft provides the station’s only connection from street level to the concourse and platforms below. Two passenger adits connect the entrance shaft to the single-bore tunnel at the concourse level, while one utility adit connects the utility shaft within the entrance structure to the tunnel track level. Additional ventilation adits connect the extended concourse level to vertical shafts extending to street level.

West Portal: The West Portal is located south of Newhall Yard and west of Newhall Street. A service stair and equipment-access stair are located east of the portal opening adjacent to the north track and connect with ancillary equipment rooms at track level. A signal house is located at grade above the tracks.

East Portal: The East Portal is located where Las Plumas Avenue transitions into North Marburg Way. A service stair and equipment-access stair are located east of the portal opening adjacent to the north track and connect with ancillary equipment rooms at track level. An electrical and communications building is located at grade above the tracks.

East & West Mid-Tunnel Egress, Ventilation and Transition Facility: These wayside facilities provide enhanced emergency-egress capability at each end of the stacked single-bore tunnel configuration, allowing evacuation of a full train operating on either guideway. The facilities also house tunnel emergency-ventilation equipment and related support rooms, an auxiliary substation, a mid-tunnel gap-breaker station, communications systems, and an emergency-egress route extending from the 700-foot-long enhanced emergency walkway within the tunnel to a designated point of safety at street level. Most program spaces are located within a single-wall-system, cut-and-cover structure below street level, while the remaining spaces are located in single-story structures and secured open areas above grade on VTA property.

Description: The BART Silicon Valley Extension Phase II project is a six-mile, four-station extension that will bring BART heavy-rail service from Berryessa/North San Jose through downtown San Jose to the City of Santa Clara. The project includes an approximately five-mile tunnel; three underground stations at 28th Street/Little Portugal, Downtown San Jose, and Diridon; one at-grade station in Santa Clara; associated wayside facilities; and maintenance facilities. All four stations include center-boarding platforms. The MMW General Engineering Joint Venture is responsible for the project, with AVA serving as part of the design team. The single-bore tunnel portion is planned for design-build delivery, while the station contracts are planned for design-bid-build delivery.

Size: 4.8 mile BART project