Performance and behavior of existing buildings above the Los Angeles Metro Tunnels

The construction of the Los Angeles Metro’s second segment in downtown Los Angeles is generally restricted to public rights-of-way. In several instances, major directional changes of approximately 90 degrees are required on relatively large-radius curves to facilitate tunnel alignment shifts from one street to another and maintain operational speeds. In these instances, the alignment has traversed private rights-of-way and passed below existing structures. This paper describes the underlying geological conditions, tunneling-induced ground settlements and performance of several multi-story structures, including wood-framed apartment buildings and high-rise glass and metal-clad office buildings.