Random seismic response analysis of adjacent buildings coupled with non-linear hysteretic dampers

Coupling adjacent buildings with supplemental damping devices is a practical and effective approach to mitigating structural seismic response. This paper is intended to develop a method for analyzing the random seismic response of a structural system consisting of two adjacent buildings interconnected by non-linear hysteretic damping devices. By modelling the buildings as multi-degree-of-freedom elastic structures and representing the hysteretic dampers with the versatile Bouc-Wen (BW) differential model, an augmented state differential equation is formulated to describe the vibration of the coupled structural system under non-white random seismic excitation. After dealing with the non-linear hysteretic dampers using stochastic linearization technique, a non-linear algebraic Lyapunov equation is derived from which the system mean square response is iteratively solved. The developed method is applicable to the structural system with an arbitrary number of storeys and with connecting dampers at arbitrary storeys. The results of the analysis demonstrate that non-linear hysteretic dampers are effective even if they are placed on a few floor levels. In particular, this type of damping device offers a wideband vibration suppression for earthquake attacks with either low- or high-dominant exciting frequencies. Parametric studies also show that optimum damper parameters and numbers exist which minimize the random seismic response.