Phase I of VTA’s BART Silicon Valley Extension, Berryessa Extension (SVBX), is about 10-mile long with two passenger stations. This extension begins at the Warm Springs station in Fremont, proceeds through Milpitas, and ends in the Berryessa area of north San Jose.
PARIKH is the geotechnical engineer-of-record (EOR) who provided geotechnical recommendations and design for all project elements, which include the followings:
- Three major underground trench structures with associated grade separation structures and pump stations,
- One underground passenger station (Milpitas Station),
- One elevated passenger station (Berryessa Station),
- One cut-and-cover tunnel with three ventilation structures (at the intersection of Sierra and Lundy),
- A thirty-span viaduct supported on more than 1,000 concrete driven piles,
- Two approach embankment up to about 35 feet supported by MSE walls filled with Lightweight Cellular Concrete (LCC),
- Several bridge structures (vehicular bridge and pedestrian overcrossings),
- Waterline relocation (42-inch and 66-inch diameter),
- Wayside facilities,
- Retaining walls and sound walls, and
- At-grade tracks.
The engineering tasks consist of deep foundation design (axial and lateral), shallow foundation design, lateral earth pressure, liquefaction potential assessment and mitigation (stone columns by Hayward Baker), settlement analysis, Soil-Structure-Interaction (SSI) analyses (2D and 3D), selection of ground motion time histories, development of test pile program, and interpretation of static pile load tests. PARIKH also provided recommendations for earthwork, grading, and excavation bottom stability.