Uniform damping ratio-based design method for seismic retrofitting of elastoplastic RC structures using viscoelastic dampers

Abstract

A simple design procedure is proposed for seismic retrofitting of existing structures using viscoelastic dampers (VEDs) based on the uniform damping ratio (UDR) concept to make full use of each damper. The UDR concept states that the equivalent damping ratios, which represent the energy dissipation capacities of the dampers, are the same for each installed VED. The stiffness and damping characteristic parameters of the damped structure can be formally decoupled using UDR-based derivations, which simplify the determination of the VEDs’ parameters. The generalized single-degree-of-freedom method and pushover analysis are adopted for a fast estimation of the seismic response of the damped elastoplastic structure. Taking the response reduction ratio as the design target, a seismic retrofit design procedure is proposed based on the UDR concept to meet the performance demand. Finally, a six-story frame is adopted to illustrate the proposed design method. The dynamic analysis results show that the seismic responses of the structure are well-controlled, as expected, and that the installed VEDs are used effectively. The conclusion can be drawn that the UDR-based design method for retrofitting an existing structure using VEDs is rational and effective.