梁式桥抗震设计的弹塑性位移反应谱  

Elasto-plastic response spectra for beam bridge's aseismic design

作　　者：李宇[1] 王森[1] 车艳阳 武芳文[1] 

机构地区：[1]长安大学公路学院旧桥检测与加固技术交通行业重点试验室,西安710064

出　　处：《振动与冲击》2015年第10期1-5,共5页Journal of Vibration and Shock

基　　金：国家自然科学基金资助项目(51408042;51408040);陕西省自然科学基金资助项目(2014JQ7253);中央高校基本科研业务费专项资金资助(2013G1211006)

摘　　要：合理选取四类场地320条强震记录,研究地震动特性及恢复力模型动力参数对弹塑性位移谱与残余位移谱影响。结果表明,给出某一标准设防烈度的弹塑性反应谱,其它设防烈度下弹塑性反应谱可据PGA设防烈度与PGA标准烈度比值调整获得;可忽略屈服后刚度比对弹塑性位移谱影响,但应选择偏于保守的屈服后刚度比统计残余位移谱,由此建立的残余位移谱只适用短周期、低延性一般规则桥梁中、低矮桥墩的抗震设计;阻尼比与位移延性比为影响弹塑性位移谱及残余位移谱重要因素,阻尼比增大会减少桥梁非弹性变形及震后残余位移。基于该结果建立适用于我国梁式桥抗震设计的弹塑性及残余位移谱,为考虑残余位移影响的梁式桥基于性能的抗震设计提供重要参考依据。With 320 strong ground motion records of four sites appropriately selected, the elasto-plastic dynamic analysis was performed to study the effects of characteristics of earthquake motions and dynamic parameters of a restoring force model on elasto-plastic displacement spectra and residual displacement spectra. The study results showed that elasto- plastic response spectra of other protected earthquake intensity can be obtained by adjusting elasto-plastic response spectra of a standard protected earthquake intensity according to the ratio of PGA for protected earthquake intensity to PGA for standard protected earthquake ; effects of yielding rigidity ratio on elasto-plastic displacement spectra can be neglected, but conservative yielding rigidity ratio is chosen to establish residual displacement spectra which can be applied in low and medium-height piers＇ aseismic design of general regular bridges with short natural periods and low ductility ; elasto-plastic displacement spectra and residual displacement spectra are affected obviously by both damping ratio and ductility, elasto- plastic displacements and residual displacements of bridge decrease with increase in damping ratio. Based on the above results, the elasto-plastic displacement spectra and residual displacement spectra applicable to aseismic design for Chinese bridges were established. They provided an important guidance for performance-based aseismic design of beam bridges considering the effects of residual displacements.

关 键 词：弹塑性反应谱 抗震设计 地震动峰值加速度 屈服后刚度 延性 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]