连续梁桥纵向地震碰撞反应参数研究

Parametric study of longitudinal seismic pounding response for continuous girder bridges

针对连续梁桥在地震作用下伸缩缝处的碰撞现象,建立了考虑支座非线性和墩柱弹塑性的碰撞模型。在此基础上,应用非线性时程方法研究了纵向地震作用下连续梁桥相邻联的非同向振动和伸缩缝处的碰撞效应。分析结果表明:影响碰撞反应的主要因素是相邻联的周期比和基本周期的大小,相邻联的质量比、伸缩缝间隙大小以及墩柱的弹塑性等因素对连续梁桥地震碰撞反应也有重要影响。同时还发现:碰撞对高度不同向振动的相邻联影响较大,当相邻联的周期比T1/T2>0.7时,碰撞对连续梁桥纵向地震反应的影响较小。

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 elastoplastic 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.