Analytical Study on the Dynamic Properties of Viscoelastically Coupled Shear Walls in High-Rise Buildings

An innovative method of using viscoelastic (VE) dampers as coupling members between reinforced concrete shear walls has been recently developed for enhancing the wind performance and seismic resilience of tall buildings. Although three-dimensional finite-element models are used for the final design of such systems, fundamental analytical models that can be used to gain broader insights into their dynamic response have not yet been developed. Therefore, in this paper a sixth-order partial differential equation governing the dynamic properties of tall shear walls coupled using VE dampers is derived by explicitly taking into account the stiffness of the connecting elements as well as that of the slab directly above the dampers. The governing equation is solved numerically using the Taylor series expansion method and the periods and added damping ratios in various modes of vibration are evaluated. It is found that for given frequency independent VE material properties, the added damping ratios of such systems are independent of the mass of the building. Analyses using a commercially available VE damper by taking into account the frequency dependency of the VE material revealed that progressively higher maximum damping ratios are achieved in higher modes of vibration. Based on the conclusions derived through the analytical formulation, recommendations are provided for enhancing the efficiency of VE dampers in tall buildings. (C) 2017 American Society of Civil Engineers.