A generic structural pounding model using numerically exact displacement proportional damping: Fid-Bau Portal

A generic structural pounding model using numerically exact displacement proportional damping

Khatiwada, S. / Chouw, N. / Butterworth, J.W.

Highlights • A generic impact model that can be either linear or non-linear. • Exact solution of Hunt–Crossley model from viscoelastic energy loss considerations. • First pounding force model with displacement proportional damping derived with no approximations. • Evaluation of pounding force models from previous impact force experiments with calculated values of restitution coefficient.

Abstract Pounding damage in bridges and buildings range from minor aesthetic effects up to major structural damage inducing building collapse or bridge girder’s unseating. This study proposes the Hunt–Crossley model, a generic model that can have either a linear or nonlinear force–deformation relationship, for the analysis of building pounding. This model has been extensively employed in Mechanical Engineering. There are several approximate solutions for the damping of the model and one of them has been introduced as the ‘Hertzdamp’ model for structural pounding analysis. The exact solution of damping constant for this model has been presented here. The performance of the linear and nonlinear Hunt–Crossley models in simulating impact force between concrete bodies is compared against other existing pounding models, namely: linear viscoelastic, nonlinear viscoelastic and modified linear viscoelastic models. The nonlinear Hunt–Crossley model best predicted the contact force while the linear Hunt–Crossley model had twice the normalized error of the Hertzdamp model, which was still only half as much as the error in other three models. Finally, a numerical simulation of pounding of bridge segments at an expansion joint is conducted with all models. It was observed that the pounding force predictions from Hunt–Crossley models are similar to that obtained in impact experiments while other models produced very different force developments. The Hunt–Crossley models do not have the discontinuities i.e. negative force, instantaneously high initial force or discontinuous transition between deformation and restitution phases of impact which are present in the other models.