Designing Resilient Structures Subjected to Abnormal Loads

摘要

In the design of structures, incorporating resilient structural systems is important to protect the structures in extreme or abnormal load events. In many cases, these systems are necessary to ensure continued operation of an essential facility, although it is also important in protecting the investment associated with a major development, or the preservation of historic buildings. Various systems have been developed to accommodate abnormal loads caused by seismic ground motions that are designed to create a high level of resiliency. The intent of this paper is to consider resiliency for a range of building types and the benefits of enhanced seismic structural systems when subjected to extreme loads. Because the Ninth District U.S. Court of Appeals, San Francisco, constructed in 1905, is so important historically, the building was seismically retrofitted to include friction pendulum bearings under existing columns, located just above the foundation level. At 365 Main Street, San Francisco, an existing 1940s non-ductile reinforced concrete warehouse was converted into a state-of-the-art internet co-location facility by introducing seismic isolation as well as an entirely self-sufficient fully redundant building services systems allowing for continued operation after an extreme seismic event. The Cathedral of Christ the Light in Oakland, California, combines seismic isolation with a reinforced concrete structure to achieve a building with a desired life of hundreds of years, even though the site is only a few kilometers from the Hayward Fault. The 222 South Main Office Building, Salt Lake City and the San Diego Central Courthouse use a diagonal system of unbonded braces and viscous dampers respectively to address building resiliency.