Optimum Design of Hybrid Base Isolation and Tuned Liquid Damper Systems for Structures under Near-Fault Ground Motions

Abstract

Near-fault movements produce earthquakes with very large displacements, which are known for their destructive properties. The increase in the number of stories of a structure isolated from the base increases the weight of the structure, and this limits the mobility of the isolator. Especially in near-fault earthquakes, the addition of a damper is recommended to address this problem. The focus of this study is to investigate the effect of the hybrid use of a seismic isolator and a tuned liquid damping device on the control performance of a structure under near-fault earthquakes. For the hybrid system, a seismic base isolator is installed at the base of the structure and a tuned liquid damping (TLD) device containing water is installed at the top story of the structure. The performance of the isolator system under near-fault earthquakes for different damping and mobility capacities is investigated. The isolator and damper properties were optimized by the adaptive harmony search algorithm (AHS) to minimize the maximum acceleration, and critical earthquake analyses were performed. The control performance of the hybrid system was compared with the structural system using only the isolator. As a result of the study, it was observed that adding TLD to the isolator system reduces the isolator damage caused by large displacements in the isolator story and that the hybrid system requires a lower isolator period requirement under pulse near-fault earthquakes compared with no-pulse near-fault earthquakes.