结构抗风设计敏感性分析

Wind-sensitivity in design of structures

从结构随机风振分析的基本理论出发,通过对脉动风荷载特性与结构动力特性的探讨,提出了影响结构风振响应的3种关键效应,即尺度效应、频率效应和模态效应,推导了表征这3种关键效应的无量纲系数;在此基础上,提出了结构风敏感度的概念,并推导了以系统应变能为响应指标、以尺度效应系数、频率效应系数和模态效应系数表示的结构风敏感度计算公式;通过对典型屋盖结构的风敏感度分析,验证了相关理论的正确性。研究表明,风敏感度概念反映了结构的风振响应本质特征,实现了对结构风敏感性问题的客观、定量描述,是对现有结构抗风设计理论的一个补充。

The sensitivity to fluctuating wind loads of a structure is a ground basic in the wind-resistant design theory.However,it still remains unresolved concerning how to describe the wind sensitivity quantitatively.Therefore,it is necessary to establish a method with physical connotative meaning to solve the problem mentioned above.Based on the basic theory of random wind-induce vibration analysis,the correlation of the characters of the fluctuating wind and the dynamic characters of the structure are summarized considering time and space factors respectively.The main factors influencing the wind-induced response are grouped to three key effects： size,frequency and mode.The wind-sensitivity conception of a structure is putted forward based on these studies,and a formula for calculating the wind-sensitivity of a structure is derived by considering the strain energy of a system as the response index.The correlated theory is verified through the analysis of the typical roof systems.The study indicates that the wind-sensitivity conception reflects the essential characteristics of wind-induced response,and it can describe the problem about wind-sensitivity objectively and quantitively.Moreover,it provides an effective way to further recognize the wind-induced response mechanism of various structures.