Design method of structural retrofitting using viscous dampers based on elastic–plastic response reduction curve

Abstract

Installation of viscous dampers has been demonstrated to be an effective method to perform seismic retrofitting of a structure. However, most of the existing design methods are based on the elastic stage of the primary structure. The proposed study presents an alternate method for retrofit design of a structure using viscous dampers whilst considering inelastic behaviour of the primary structure. The said method makes use of the elastic–plastic response reduction curve (EPRRC) to reflect the relationship between characteristic parameters of the viscous damper, supporting brace, and response of the viscous-damper-equipped primary structure. Use of this method ensures that reduction in storey drift as well as shear force is simultaneously realized within the EPRRC coincident reduction region. Thus, parameters concerning the required dampers and supporting braces can be obtained from EPRRC in accordance with target performances of the damped structure. Comparison between a traditional elastic response reduction curve (ERRC) and EPRRC indicates that ERRC tends to overestimate the performance of damped structures. Nonlinear time-history analysis was performed to verify the effectiveness of the proposed method when applied to a benchmark model. Additionally, probabilistic reliability of the said method was determined via incremental dynamic analysis. Results demonstrate that the proposed design method can effectively satisfy design requirements under different seismic intensities.