斜交简支梁桥纵向地震碰撞反应精细化研究

Refined study on longitudinal seismic pounding responses of simply supported skewed girder bridge

为精细化分析斜交简支梁桥地震碰撞反应,首先基于Hertzdamp碰撞理论,采用开放式地震模拟软件Open Sees建立能够考虑碰撞过程中摩擦作用的斜交简支梁桥精细化计算模型;然后从动力特性、动力反应层面验证模型的可靠性;最后采用三维精细化计算模型分析斜度、摩擦对斜交简支梁桥纵向地震碰撞反应的影响。结果表明:梁体与桥台间最大碰撞力的产生位置随着斜度的变化而改变;最大碰撞力的大小不仅与斜度有关,而且与斜交桥梁端与桥台间摩擦因数也存在一定关系;摩擦作用削弱了斜度对梁端锐角处纵向最大位移的影响,大幅度减少上部结构峰值转角,使峰值转角最大值滞后在较大斜度时出现;不考虑摩擦作用会高估锐角处梁端纵向最大位移反应。

For refined study of the seismic pounding responses of the simple supported skewed girder bridge （SSGB）, firstly, based on the Hertzdamp pounding theory, a refined calculation model considering the friction effect during an SSGB collision was built by open-source seismic software OpenSees; then the reliability of the model was verified from the level of dynamic characteristics and the dynamic response; finally, the 3 D refined calculation model was used to analyze the influence of the skew degree and friction effect to the longitudinal seismic pounding responses of SSGB. The results indicate that the position that produces the maximum impact force between deck and abutment changes with the change of the skew degree ; the skew degree and the friction coefficient can influence the maximum impact force. The friction between deck and abutment weakens the influence of the skew degree to the largest longitudinal displacement in acute position of deck＇s ends, reducing the peak rotation angle of deck significantly and making the maximum value of the peak rotation angle appear at the bigger skew degree; the largest longitudinal displacement in deck＇s ends will be overestimated if the friction effect is not considered.