Cost-Effective Seismic Station-Tunnel Connections on Westside Subway Extension Project Section 1

摘要

When designing metro systems for strong seismic motions there is a wealth of information on the design of both conventional bored tunnels and cut and cover structures like stations. However, there is very little literature treating the connection between the two. This paper describes how the closed form solutions often used to approximate the longitudinal soil-structure behavior can underestimate the movements at connections, and how these shortcomings were overcome in the Westside Subway Phase 1 project in Los Angeles. With reference to previous projects in the LA area, some useful conclusions for future designs are drawn, including how larger displacements can be allowed for in commonly used details with negligible impact on their cost.