A non-smooth dynamic model for pounding analysis of simple span bridges under seismic excitations

Small- and medium-span simply supported bridges are widely used in highway bridges, which are vulnerable to pounding-induced damage under strong earthquake action. Thus, developing a precise and appropriate mechanical model is crucial for practitioners and researchers to investigate the pounding effect and damage mechanism of bridges under seismic excitations. This paper presents a non-smooth dynamic framework to address the pounding problem of simple span bridges under seismic excitations. Normal pounding force and corresponding transverse friction force are added to the fundamental dynamic equation using constrained Jacobian matrixes, and the motion equation for the system is created to portray the pounding behavior of the structure at the pounding locations. The shake table test results obtained by the author from the previous experiment were employed to validate the proposed method. The comparison shows that the proposed model can precisely predict the pounding scenario of simple span bridges under seismic excitations. Finally, the influence of the coefficient of friction (CoF), the coefficient of restitution (CoR), and the nonparallel pounding effect (NPE) on the peak girder rotation (PGR) are analyzed. It is found that simple span bridges can exhibit in-plane rotation if the CoF is more than 0.3 and the rotation is not significantly affected by an increase in CoF from 0.4 to 1.0.