在役桥梁结构延性系数的动力评价方法

以桥墩的基本振型函数为基础,推导出基于试验动力参数的在役桥梁结构延性系数的计算公式,并给出了结构非弹性地震力的求解方法。对室内钢模型桥利用冲击力锤法进行了模态试验和静力对比试验,实测参数与理论值相差仅2%,在此基础上利用给出的公式可以求得桥墩的变形增加系数为2.78。结果表明,在场地土条件未知的情况下,利用动力试验法对在役桥梁结构延性系数进行评价是可行的。

Dynamic assessment method of ductility coefficient for exsiting beam bridges

Based on the pier's mode shape function, this paper studied the methodology of structure ductility coefficient by modal test and the procedure of the structure's inelastic seismic force. A modal test using impact excitation method as well as static test was carried out indoors in a steel model.The dynamic parameter derived from the test had an error of 2% compared with the theoretical one. Using the formula presented in the paper, the pier's deformation coefficient was calculated,which was 2.78. The results indicate that if the foundation on which the bridge is sited is difficult to predominate,the dynamic test is an effective measurement for studying the bridge's ductility coefficient. The method can be used to evaluate the seismic resistance performance of existing bridges. 4 figs, 7 refs.