Eccentric Bracing in Tall Buildings

Primary concerns in the design of high-rise buildings, particularly those located in seismically active regions, are the control of interstory drift and the ability of the structure to withstand inelastic deformations. The design of the 47 story 4 Embarcadero Center building in San Francisco, California, utilizes a recently developed structural system that provides economical control of interstory drift, as well as sufficient ductility to enable the structure to perform satisfactorily in the event of a major earthquake. The use of eccentric bracing elements is the key to this structural system. This paper describes how an eccentric bracing scheme was used to satisfy the requirements for both drift control and ductility in the design of a high-rise structure located in a zone of high seismic exposure.