Seismic Response Study of Degraded Viscous Damping Systems for Tall Buildings in China

During a seismic event, the fluid-viscous dampers utilize the action of solids to enhance the performance of structures subjected to transient environmental disturbances for general shock and vibration mitigation purposes. The conventional cylindrical viscous dampers contain compressible silicone oil which is engaged to flow during a disturbance through the action of the stainless steel piston rod with a bronze head. Possible compressible oil leakage in damaged damping systems may negatively affect the response of the degraded damping system and, ultimately, the response of the entire structure, during a seismic event. It creates a gap or lapse in the force-displacement response. This paper investigates the seismic response of Beijing Yintai Center for various viscous fluid leakage percentages in damping systems which are mainly manufactured and supplied by Taylor Devices (U.S.) and the Beijing QITAI shock control and scientific development in China. One of the main objectives of this study is to investigate the performance of viscous dampers under different conditions of possible leakage volumes against their basic response characteristics. The damper is able to handle a portion of the assigned displacement time history without developing any reaction force. However, when the displacement of the internal piston reaches a sufficient level to regenerate fluid pressure, the damping force trend is restored through a “delay” whose length depends on the amount of the fluid leakage. The study is based on the time history analysis of selected and scaled earthquake records according to the ASCE 7-10 along with the numerical analysis of simulated damaged/leaking damper devices using finite element and structural analysis software. The analyses results demonstrate the change in performance of the structures with degraded damper devices. The inter-story drifts and base shear values are dramatically increased in structures with degraded damper devices.