T.Y. Lin International led the seismic retrofit design of five Bay Area Rapid Transit (BART) underground stations in San Francisco and Oakland, California including Glen Park, MacArthur, Church Street, 12th Street, and 19th Street stations. This project is the 13th of 14 contracts issued for the BART Earthquake Safety Program, a $1.3 billion effort to upgrade vulnerable portions of the original BART system. T.Y. Lin International performed the retrofit work for Bechtel Infrastructure Corporation, BART’s general engineering consultant for the Earthquake Safety Program.
- Retrofit of five underground stations
- Construction costs reduced by approximately $20 million
The primary challenge of this project was to reduce retrofit costs by using high-powered analytical techniques and state-of-the-art earthquake engineering, including soil-structure interaction (SSI) and next-generation attenuation (NGA) models for seismic loading criteria. These techniques provided real construction cost savings by reducing uncertainties, both for new designs and seismic retrofits. For two of the four stations—Glen Park and 12th and 19th Street Stations— T.Y. Lin International was able to determine the safety of the structures.
Despite the inherent challenges of retrofitting underground structures, T.Y. Lin International’s goal for the project was to develop cost-effective, innovative retrofit solutions that balance cost with operability. Initial cost estimates in a preliminary strategy report were projected at $25 million, however, T.Y. Lin International’s design brought an excess of $20 million in savings to the bottom line. Further studies may allow for an even greater reduction of retrofits.