【摘要】 高墩桥梁的地震响应与传统的中低墩桥梁有很大差别,我国现行桥梁抗震规范对此没有规定。为了合理评估高墩大跨桥梁的抗震性能,以一座连续刚构桥为研究对象,采用OpenSees建立弹塑性有限元动力分析模型,从PEER地震数据库中选取了15条地震记录进行增量动力分析(Incre-mental dynamic analysis,IDA),利用Ramberg-Osgood函数对控制参数进行统计,从而得到了结构概率分位值为10%、50%和90%的IDA曲线,结合定义的损伤状态对结构的抗震性能进行了评估;根据墩身最大曲率分布得到了塑性区域长度,提出了根据最大曲率分布估算墩顶目标位移的方法。结果表明:利用R-O函数统计得到的IDA概率分位曲线能很好地体现桥梁抗震性能,并能给出满足相应性能水准的可靠等级。在强震作用下,高墩结构塑性区域长度与各国规范计算结果吻合,按墩身最大曲率分布估算墩顶位移与IDA分析结果吻合较好,弥补了规范的不足。更多还原

【Abstract】 The seismic responses of bridge with high piers,for which the seismic design criteria are unavailable,are quite different from the regular bridge.In order to assess the seismic performance of the irregular bridges with high piers and long spans,a continuous rigid frame bridge is taken as an example.Using OpenSees,a dynamic elastic-plastic finite element model is built,and then the Incremental Dynamic Analysis is carried out with 15 seismic ground motions selected from the PEER database.With the Ramberg-Osgood equation,a statistical analysis of the controlling parameters is performed,and then by ascertaining the 10%,50%,90% IDA responses and combining with the defined damage to the structure,the seismic performance is accessed.According to the distribution for maximum curvature along the piers,the length of the plastic zone and the formulas for estimating the beam displacement based on the curvature are proposed.The results show that IDA fractile curves can well measure the seismic performance,and can evaluate the reliability at the corresponding performance level;besides,under the strong ground motion,the length of the plastic zone is consistent with the criteria at home and abroad and the formulas for estimating the beam displacement meet the IDA analysis results well.更多还原