TYLin led the seismic retrofit design of four Bay Area Rapid Transit underground stations in San Francisco and Oakland, California.
This project was the 13th of 14 contracts issued for the Bay Area Rapid Transit (BART) Earthquake Safety Program, a USD 1.3 billion effort to upgrade vulnerable portions of the original BART system. TYLI performed the retrofit work for Bechtel Infrastructure Corporation, BART’s general engineering consultant for the program. The projects enhance the safety and reliability of the BART system during seismic events.
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 provide real construction cost savings by reducing uncertainties, both for new designs and seismic retrofits.
Despite the inherent challenges of retrofitting underground structures, TYLin’s goal was to develop cost-effective, innovative retrofit solutions that balance cost with operability.