The effect of modified linear viscoelastic impact models on the pounding response of a base-isolated building with adjacent structures

During strong earthquake excitations, base-isolated buildings may collide, either with the surrounding moat wall or with adjacent buildings. This unfavorable possibility has been recently investigated through numerical simulations and parametric studies. A very important issue regarding these numerical studies is the modeling of impacts, which are typically simulated using various types of force-based impact models. This paper parametrically investigates the effects of impact modeling characteristics on the overall structural response of a base-isolated building that is subjected to seismic pounding. Specifically, the Kelvin Voigt impact model and various other modifications of this linear viscoelastic impact model are considered in the performed analyses. In order to effectively and efficiently conduct this investigation, a specialized software application, which has been specifically developed to simulate buildings subjected to pounding, is employed. A smooth bilinear (Bouc-Wen) model is used for the simulation of the seismic isolation system. The influence of particular impact parameters, as well as the width of the seismic gap, on the dynamic response of the structure under strong excitations is quantified. Furthermore, the effect of using different impact models for the calculation of the impact forces on the overall seismic response during pounding is simulated and discussed, since a reasonable question arises regarding the accuracy of an impact model, which is a simplification of the actually very complicated impact phenomenon.