静力非线性方法用于桥梁高墩抗震性能分析

Application of Pushover Method to Seismic Performance Evaluation of Tall Piers for Bridge

高墩桥梁由于结构本身的特点,墩高使得高阶振型的影响更明显,笔者基于"等效振型高度"的概念对通常采用的MPA(Modal Pushover Analysis)方法提出改进,并采用几种不同侧向力分布模式的Pushover以及动力时程分析对桥梁单墩进行对比分析,以研究改进的MPA法应用于桥梁高墩抗震性能分析的计算精度和有效性。分析结果表明,当地震动强度较小时,MPA法和改进MPA法可以较好的改善计算结果;随着地震动强度的增大,改进MPA法的计算精度优于MPA法。

For bridge with tall piers,the influence of higher modes on structural responses becomes more evident.Modified MPA method（MMPA） which is based on MPA theory and the concept of ＂equivalent mode height＂ is presented.To verify the effectiveness and the degree of accuracy of this method,several Pushover methods including MPA and MMPA methods were adopted to analyze tall piers for bridge,and then compares the results with that in dynamic time-history analysis.It is shown that MPA and MMPA methods can improve computational accuracy comparing with other normal Pushover methods when seismic intensity is lower,whereas the computational accuracy for MMPA methods is superior to that in MPA analysis with the seismic intensity becoming larger.