桥梁隔震设计中几种等效线性化方法比较研究

对LRB桥梁设计领域中流行的几种等效线性化方法进行了研究。对各个方法的等效刚度与等效阻尼比的计算进行了比较，确定了其参数敏感性，并对导致其不同的原因进行了初步分析，并分别比较了传统的经典阻尼理论与最新的模态应变能理论求解隔震系统阻尼比的计算方法。针对系统阻尼对桥梁设计反应谱的影响，列举了包括直接位移法在内的几个影响系数计算公式，分析了其中的异同。以一座实桥为例，通过与非线性时程分析比较，对各个等效线性化方法进行了评价。所有的方法大部分情况下均高估了结构的位移响应，即均低估了结构的阻尼。不同方法对结构力与力矩响应的评估水平不同，但是对隔震设计均能起到较好的指导意义。

Comparative Research on Equivalent Linearization Methods in Bridge Isolation Design

Several different equivalent linearization methods including AASTO,JPWRI,and California standards and the experiential formulae suggested by Hwang,Iwan and Jara on the LRB-bridges design were discussed.Firstly,the equivalent damping ratio and equivalent stiffness of these methods were computed and compared each other.As the result of the intercomparsion,sensitivity of these parameters was obtained and the reasons were studied primary.The calculating methods of systems damping ratio based on the classical damping theory and the modal strain energy theory was compared in detail.The result shows that the latter method is much more practical for design.Secondly,concerning the influence of system damping on LRB-bridge design spectrum,series of influence parameter including the direct displacement-based method were computed and compared.The influence parameter suggested by direct displacement-based method is not properly for isolator bridge intensity design.At last,take a practical continuous bridge for example,the accuracy of these equivalent linear methods were estimated,compared to the inelastic time-history result.It's found that displacement responses are overestimated by these methods,and different methods obtain different forces and moments,while all of these methods are suggestive for isolation design.