Santa Clara Valley Transportation Authority / San Jose, California
The Silicon Valley Rapid Transit Project (SVRT) extends the existing Bay Area Rapid Transit (BART) third rail transportation system 16.3 miles from Warm Springs to Milpitas, San Jose, and Santa Clara.
The first 11.8 miles are at grade, elevated, or in trench from Warm Springs to the eastern portal structure near Alum Rock. From there, the system continues 4.5 miles underground through downtown San Jose, passing through four cut-and-cover stations (Alum Rock, Civic Plaza/San Jose State University, Market Street, and Diridon/Arena), two ventilation structures, and a crossover to arrive at the west portal in Santa Clara. The system then continues at grade to the Santa Clara surface station near the existing Santa Clara Caltrain station.
Mott MacDonald was responsible for the design and construction management of the tunnel segment, interagency coordination, and the project cost and schedule controls for the entire SVRT project. In addition, we provided expertise in ventilation and computational fluid dynamics (CFD) modeling to support the fire/life safety evaluation of the design.
Mott MacDonald was responsible for the ventilation study of Milpitas station. The objective of the study was to evaluate whether tenable conditions of the station could be achieved during a fire incident within the evacuation time by utilizing a natural ventilation design concept, and to decide whether a mechanical ventilation system was required. The tenability criteria are defined in the 2001 California Building Code (CBC) and the 2007 NFPA 130.
- Explored different ventilation strategies for the station
- Developed scheme to assess the wind effects on smoke movement & the performance of the smoke natural ventilation system by using the Santa Clara Valley Transportation Authority's CFD field model approach
- Provided recommendation for design modification of the venting system to ensure a successful natural ventilation for smoke control