ELASTIC SEISMIC RESPONSE OF BUILDINGS WITH SUPPLEMENTAL DAMPING

Supplemental damping devices can add significant amounts of energy dissipation in buildings. While most previous studies of the earthquake response of buildings were confined to the small damping inherent in structural and nonstructural components, the consequences of adding from 10 to 150 percent of critical damping as supplemental damping on the elastic response behavior of buildings is studied. The study is divided into three parts: single degree of freedom systems, multidegree of freedom systems, and distributed parameter systems.; For single degree of freedom systems, a relationship between seismic displacement response and the amount of damping was established. Similarly a relationship between the commonly used pseudo spectral acceleration and the actual absolute acceleration was established for these higher damping cases.; The consequences of adding supplemental damping in multistory buildings was studied using simply coupled stiffness systems as well as using beam and column flexibilities. The displacement and energy component responses were used to develop an understanding of the behavior of buildings with large damping. The dampers were modeled considering changes in physical properties during the excitation. An example design is used to illustrate the procedure developed in this study.; The optimum distribution of supplemental damping in a building for the highest efficiency of damper utilization was studied using a distributed parameter system.; The main conclusions of this study are: (1) Supplemental damping is very effective for reducing structural response to earthquake excitation. (2) The relationship established to relate the displacement response of a structure as a function of damping was shown to be reliable for predicting the displacement response of a structure. It was effective also for selecting the damping required to limit the response to prescribed limits. (3) The optimum distribution of supplemental damping in a simply coupled multistory building is proportional to the slope of the fundamental mode shape for that building.