Parametric study of longitudinal seismic pounding response for continuous girder bridges

Based on pounding phenomenon at expansion joints of continuous girder bridges during earthquakes,a simplified model that considered the nonlinear behaviors of bearings and the elasto-plastic behaviors of piers was developed to study the effects of pounding.This model was used to investigate the out-of-phase vibrations and pounding effects of adjacent girders at expansion joints by the nonlinear time-history analysis method.The results show that the primary factors affecting the pounding response are the period ratio and the values of natural periods of adjacent bridge segments,additional factors,such as the mass ratio of adjacent bridge segments,initial gap at expansion joint and yielding of piers have important effects on longitudinal seismic pounding responses in continuous girder bridges.It also has been determined that pounding is most severe for case with highly out-of-phase adjacent bridge segments and pounding effect is less pronounced when the period ratio of adjacent bridge segments is larger than 0.7.