Multiple performance criteria-based risk assessment for structures equipped with MR dampers

In this paper, a procedure to seismic risk assessment of structures equipped with magnetorheological (MR) damper considering multiple performance criteria has been presented while accounting for uncertainties of the applied excitation, structure and damper properties, and damage state thresholds. The procedure employes the Latin hypercube sampling (LHS) method to generate 30 sample random MR-Structure systems and incremental dynamic analysis (IDA) has been conducted under 20 earthquakes to evaluate engineering demand parameters. Fragilities have been evaluated using the Monte Carlo simulation (MCS) method in each intensity measure and have been integrated with the hazard curve to determine the reliability during lifetime. For numerical analysis, an eight-story nonlinear shear building with bilinear hysteresis behavior has been adopted. The effectiveness of the introduced methodology is illustrated through a seismic risk assessment of the structure equipped with passive-off and passive-on MR dampers. Numerical results have shown the capability of MR dampers in significant mitigation of the seismic risk of the nonlinear structure. Moreover, it is observed that considering multiple performance criteria of the structural system, non-structural components, and MR damper stroke length and the interaction between them has led to increase the seismic risk. Also, the uncertainty of the applied excitation shows more remarkable influence with respect to the other sources of uncertainties.