Chinatown Station

Owner

The San Francisco Municipal Transportation Agency - MUNI

Client

PB / Kwan Henmi / Michael Willis JV

Cost

$1.6 billion USD

Timeframe

June 2016 — ongoing

Services performed

Conceptual, preliminary and detailed design of underground caverns, egress tunnels and mined shafts; scheduling and cost estimating; risk management; specifications and tender. Also onsite support during construction.

Description

Chinatown Station is the Northern Terminus of the Third Street Light Rail Project, which is located in a dense urban neighbourhood, underneath a busy street and directly adjacent to numerous old buildings, as well as one high-rise building. The station encompasses a Cut-and-Cover headhouse for passenger entry, three large station caverns and an emergency egress shaft. In order to minimise excavation volume and optimise cost and schedule, the ventilation ducts are located below the platform level, and routed into the headhouse.

Geology

The geology ranges from soft clay - Bay Clay to stiff sands - Colma Sands, and competent to highly fractured rock - Franciscan Formation. The groundwater table is generally above the cavern springline.

Location

San Francisco, USA

Highlights

Tunnelling in a very dense urban environment
Large NATM station caverns constructed in rock and in soft ground
Preliminary, basic and detailed design, tender support and design support during construction

Excavation and Support Sequence of Large Urban Cavern

Large Urban Cavern Under Construction

Excavation and Support Sequence - Longitudinal Section

Overall Station Layout, Headhouse and Caverns - Rendering by JV

Chinatown, San Francisco Dense Urban Neighbourhood

Station Cavern with Centre Platform, Mezzanine and Ventilation Ducts

Proposed Mitigation Measure for adjacent Buildings

Complex 3D Finite Element Analysis

Chinatown Station

Highlights

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