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Chinatown Subway Station, San Francisco, USA

Project data

Location: San Francisco, United States

The expansion of the San Francisco subway system includes the development of the 60 m long Chinatown Subway Station. The station improves access to public transportation in some of the city’s most densely populated areas. Though the architectural requirements of the station presented enormous challenges, PERI was able to develop a project-specific solution based on the VARIOKIT Engineering Construction Kit to economically construct the inner lining.

The oval-shaped underground structure, stretching up to 30 m deep was realized using shotcrete and secured with a 15 m diameter inner lining. In order to form the inner lining and carry the large and heavy formwork ring, VARIOKIT systems components were used. VARIOKIT facilitated the safe transfer of large loads while simultaneously allowing flexible adaptation to accommodate the challenging tunnel cross-section.

After the first ten concreting cycles, the tunnel shell diameter changed. Due to the flexible VARIOKIT modular construction system and patented Telescopic Posts, the supporting structure, together with the other components, was easily adapted to accommodate the new geometry.

Read the full press release 


  • in-situ concreting operations of the up to 15 m diameter inner lining of a subway station, 17 m underneath a densely populated area
  • cost-effective execution of a relatively short tunnel tube with changes in the tunnel profile
  • limited space on the construction site and only a single access to the subway station available


Tutor Perini Civil Sylmar, CA

Customer's benefit

  • Due to the high flexibility of the VARIOKIT system, as well as the high load-bearing capacity of the system components, the inner lining of the tunnel could be executed very cost-effectively
  • The low weight of the timber formwork resulted in enormous weight savings and thus reduced work requirements and logistics costs
  • Thanks to the VTC Telescopic Post, the formwork could easily be adapted to accommodate the new cross-section with relatively little time and effort
  • The prefabricated formwork elements delivered directly to the construction site simplified jobsite logistics
  • Through the know-how and the expertise of the PERI engineers, construction process could be continuously optimised
  • Accelerated shuttering and striking procedures through the hydraulic support of the VTC Tunnel Formwork Carriage

PERI solution

  • Economical execution of the inner lining by means of a project-specific VTC Tunnel Formwork Carriage and individually adapted free-form formwork
  • Continuous on-site support provided by a PERI project coordinator for optimising workflows