建筑结构抗震分析的改进反应谱法

目前各国抗震设计规范推荐采用反应谱法进行结构抗震分析。传统反应谱法需要采用地震动白噪声假定和峰值因子一致性假定，对于大规模复杂建筑结构地震响应的计算结果造成较大影响。为了摒弃上述2个计算假定，采用直接迭代法获取与规范反应谱完全等价的地震动功率谱，并计算获得振型相关系数曲面和振型峰值因子曲线。在此基础上，利用结构响应峰值的精确CQC组合公式，提出一种改进反应谱法，以获取具有明确超越概率信息的地震响应峰值。针对某复杂高层建筑结构进行抗震分析，全面剖析了传统反应谱法中地震动白噪声假定和峰值因子一致性假定的影响规律，并验证了改进反应谱法与随机振动方法具有同样的计算精度。改进反应谱法所需用到的振型相关系数和振型峰值因子可以由规范反应谱完全确定，具有良好的工程应用前景。

A modified response spectrum method for seismic analysis of building structures

At present, the response spectrum method (RSM) has been recommended for calculation of seismic responses of structures in the seismic design codes of various countries. However, certain assumptions are involved in the traditional RSM, including those that the seismic input is white noise and the modal peak factors equal the total peak factor, which may considerably affect the seismic analysis of large-scale complex building structures. To remove the above two assumptions, in the present study, the equivalent power spectrum compatible with the code response spectrum is first acquired through direct iteration, and the surface of modal cross-correlation coefficient and the curve of modal peak factor are then obtained. On this basis, leveraging the exact formula of complete quadratic combination (CQC) rule for the structural peak response, a modified RSM is proposed for obtaining the seismic peak responses with clearly specified probability of exceedance. The seismic response analysis is carried out on a complex high-rise building structure, in which the effects of the abovementioned two calculation assumptions involved in the traditional RSM are thoroughly investigated, and the accuracy of the modified RSM is validated compared with the random vibration method. As the modal cross-correlation coefficients and the modal peak factors required in the modified RSM can be completely determined from the code response spectrum, the present approach has good prospect in engineering applications.