抗震支吊架简化振型分解反应谱方法

Investigation on simplified response spectrum analysis method for seismic support hangers

为解决等效侧力计算方法因忽略建筑主体结构与抗震支吊架动力性能耦合作用影响而造成的较大计算误差,引入抗震支吊架系统动力放大系数,在主体结构振型分析反应谱法计算基础上得到抗震支吊架加速度,进而算得抗震支吊架水平地震作用;在抗震支吊架系统的周期分布特征研究基础上,分析场地类型、主体结构对动力放大系数的影响规律,得到动力放大系数概率分布模型,继而给出动力放大系数的计算推荐值。结果表明:当管线自振周期大于0.1 s时,等效侧力法不适用于抗震支吊架计算;在Ⅳ类场地下的动力放大系数相对集中;随着楼层高度的增加,动力放大系数的集中程度相对增加但平均值相对较小;在实际工程设计中,应当同时考虑上述因素和抗震支吊架本身动力特性的影响;抗震支吊架系统动力放大系数设计值宜取为1.25。

In order to address the calculation error of equivalent lateral force method due to its ignorance of coupling influence of building structures and dynamic performance of seismic support hangers,a dynamic amplification coefficient of seismic support hanger system was introduced. Then,acceleration of the hanger was obtained on the basis of vibration mode response spectrum analysis of main structures,and horizontal seismic action was calculated. Based on studies of periodic distribution characteristics of the hanger system,influence law of site type and main structure on dynamic amplification coefficient was analyzed,and probability distribution model of the coefficient was obtained before its recommended calculation value was given. The results show that as natural vibration period of pipelines is greater than 0. 1 s,equivalent lateral force method is not suitable for calculation of seismic support hangers. At class Ⅳ site,dynamic amplification factor is relatively concentrated. As structural height increases,concentration degree of dynamic amplification coefficient increases while average value is relatively small. In terms of actual engineering design,influence of above factors and dynamic characteristics of the hanger should both be considered,and design value of dynamic amplification coefficient should be 1. 25.