Impact of viscous damping models on nonlinear response of SDOF systems

Abstract

Within the context of Performance-Based Seismic Design, accurate prediction of non-linear response is essential to control structural performance. While variables such as strength, hysteretic response and earthquake characteristics impact non-linear response, the effect of the choice of viscous damping model on non-linear response using different hysteretic models in frame analysis is less obvious. Analysts will often utilize the default models available in commonly available analysis codes, which is typically proportional to the damping force considering the initial stiffness. In the research described in this paper, a parametric study was conducted using over 100 real earthquake ground motions and five different hysteretic models to assess the impact of the choice of viscous damping model on the non-linear response of single degree of freedom systems. The results of the analyses indicate that while there is variation, the choice of damping model can have a profound impact on inelastic analysis, with differences of 50% in terms of peak displacements common. Increased levels of ductility tend to have a more pronounced effect, while choice of hysteretic model also plays a role with larger differences apparent for hysteretic models with lower levels of residual displacements.