Seismic energy analysis of structures with nonlinear fluid viscous dampers-algorithm and numerical verification

To protect structures from suffering significant damage during a major earthquake, fluid viscous dampers (FVDs) have been used in both newly constructed and seismically retrofitted structures to effectively reduce dynamic responses. The main benefit of installing FVDs into structures is to dissipate larger portions of earthquake induced energy through viscous damping, thereby decreasing energy dissipation demands on structural members, which, in turn, reduces structural damage. The objective of this paper is to propose a simple numerical algorithm for analysing the dynamic response and energy transfer of inelastic structures with nonlinear FVDs. This numerical algorithm uses the state space method of dynamic analysis, an explicit time-stepping method that has proven to be both numerically accurate and time efficient, as well as the force analogy method to determine the inelasticity of structures and to quantify the corresponding plastic energy when inelastic structural behaviour occurs. Numerical verification of the algorithm is performed by comparing nonlinear time history structural responses of using a linear FVD in a single degree of freedom system. Application of the algorithm on studying the effectiveness of installing FVDs with different nonlinear power law coefficients and damping coefficients are also investigated and presented. Published in 2010 by John Wiley & Sons, Ltd.