土-结构相互作用对结构风振响应的影响

EFFECTS OF SOIL-STRUCTURE INTERACTION ON THE RESPONSES OF STRUCTURE TO WIND-INDUCED VIBRATION

通过框架结构的风振响应计算,说明土-结构相互作用(简称SSI)对结构风振响应的影响。计算结果表明:在结构的风振响应分析中,考虑SSI并不总是安全的。在土中阻尼较小时,考虑SSI后,体系的第一频率较不考虑SSI时(即所谓的“刚性地基”)明显降低,而弹性位移反而较刚性地基时的值大。后一现象在相对刚度较小时更加明显。此外,考虑SSI后,无论结构高度如何,结构各楼层的总位移总是远远大于刚性地基时的位移。这可能使人体产生明显的不舒适感。因此,在风振响应分析中应当考虑SSI效应。

Through the response evaluation of frame structures to wind-induced vibration,the effects of soil-structure interaction (SSI) on the responses of the structures are illustrated. Evaluation results show that in the response analysis of structure to wind-induced vibration,the effects of SSI on the wind responses are not always conservative. SSI can obviously reduce the first resonant frequency of the structure system. When the damping in soil is small,the elastic relative displacements of structures with SSI may be greater than that of structures without SSI. This phenomenon is more significant if the relative stiffness of the superstructure and its surrounding ground is smaller. Moreover,the total displacements of the structure with SSI are always much greater than that of the structures without SSI,which can make people produce strong uncomfortable perception. Therefore,in the response analysis of structure to wind-induced vibration,the effect of soil-structure interaction should be considered.