Seismic Characteristics of Buildings

Strength, deformability, and damping play equally important roles in seismic design. Buildings are not expected to withstand extreme ground motions by strength alone. Two example buildings are selected: a 3-story steel special moment frame (SMF) building and a 20-story steel eccentric braced frame building. Both buildings are designed to possess high strength, deformability, and damping by utilizing ordinary materials and established technologies. The lateral strength and deformability of a building are defined by its pushover curve, which is a plot between the lateral force and the deflection of the building’s center of gravity. The SMF is an excellent system for low- to mid-rise buildings because of its high deformability and damping. With an increase in height, both elastic and inelastic deflections of the SMF increase. Greater elastic deflection reduces the overall damping of the system because damping in the elastic range is low.