Abstract
Earthquake-induced pounding between insufficiently separated buildings or bridge segments, due to the out-of-phase vibrations, has been studied for several years now. A number of different impact force models have been used in order to simulate structural pounding numerically. Among them, the nonlinear elastic model based on the Hertz contact law is one of the most often used. It simulates the relation between the pounding force and deformation during impact more realistically comparing to the linear models, however, it does not allow us to simulate the dissipation of energy during impact. The aim of the paper is to compare two recently proposed models (the nonlinear viscoelastic model and the Hertzdamp model) based on the Hertz contact law with additional nonlinear damping introduced in order to simulate the energy dissipation during impact. The results for two different impact experiments as well as for the shaking table experiments on pounding between two vibrating steel towers excited by harmonic waves have been used in this study. The results of the study show that the nonlinear viscoelastic model gives smaller simulation errors in the impact force time histories comparing to the Hertzdamp model. On the other hand, the Hertzdamp model has been found to be more accurate than the nonlinear viscoelastic model in simulation of impact velocity for pounding of vibrating structures under harmonic excitation.