规范反应谱长周期段的修正

A Study on Revising Long Period Part of Response Spectrum in Chinese Code

将反应谱方法用于抗震设计有两个基本问题,合理的输入地震反应谱,以及反应谱如何组合.本文介绍合理输入的问题,对输入反应谱进行修正.与中小跨度桥梁结构不同,大跨度桥梁结构的第一阶主要自由振动周期都很长,而现有规范中反应谱适用周期比较短,长周期段存在很大问题.本文的研究目的是对现有规范反应谱的不合理性作详细说明并对进行修正.采用了强震记录准确的集集地震作为地震动输入,通过限制位移谱的方法对原有规范反应谱长周期不合理部分进行修正,使其满足长周期结构设计的要求.修正结果得到与理论相符的反应谱.将修正结果与多条强震记录的地震动进行对比,表明修正结果与强震记录是十分吻合的.

There are two problems when using the response spectrum in seismic design , reasonable input and the combination of the response spectrum .This paper tried to solve the first problem and revise the input re-sponse spectrum .For most of the large span bridges , lower mode period is very long , which is different from those of small span bridges .But the response spectrum of the current code are too short so there are problems for the long period part .The purpose of this paper is to research the reason of unreasonable code response spectrum and revise it .Chi-chi earthquake was used as the seismic input in this paper .The long period part of the re-sponse spectrum was revised according to the displacement response spectrum so that it can be used for seismic design.By comparing the revised spectrum with the earthquake response records , the result showed that the re-vised response spectrum conform to the records is very well .