Impact of Near-Fault Ground Motions on the Efficiency of Viscous-Damping Systems

Energy dissipation systems can effectively reduce the seismic demands of structures and protect them from damage. However, the effectiveness of the systems is not entirely independent from the dynamic characteristics of ground motions and may be challenged by long-period velocity pulses in near-fault ground motions. The major focus of this study is to clarify the impact of the characteristics of near-fault ground motions on the effectiveness of energy dissipation systems, particularly, structures equipped with viscous dampers. A series of response-history analyses are conducted using single degree-of-systems (SDOF) with periods varying between 0.2 and 5 seconds and damping ratios between 5% and 50% and subjected to fault-normal components of 91 sets of near-fault ground motions identified in a literature prepared by Prof. Jack Baker in 2007. The effectiveness of damping in reducing seismic demands of SDOF systems subjected to near-fault motions are discussed and a model are proposed to describe their relationship.