Design of supplemental viscous dampers in inelastic SDOF system based on improved capacity spectrum method

A simplified yet effective design procedure for viscous dampers was presented based onimproved capacity spectrum method in the context of performance-based seismic design. The amount ofadded viscous damping required to meet a given performance objective was evaluated from the differencebetween the total demand for effective damping and inherent damping plus equivalent damping resultingfrom hysteretic deformation of system. Application of the method is illustrated by means of twoexamples, using Chinese design response spectrum and mean response spectrum. Nonlinear dynamicanalysis results indicate that the maximum displacements of structures installed with supplementaldampers designed in accordance with the proposed method agree well with the given target displacements.The advantage of the presented procedure over the conventional iterative design method is alsohighlighted.