基于响应时程的大跨度空间结构等效静风荷载分析方法

Analysis method of equivalent static wind load on large-span spatial structures based on response time history

提出以特定时刻的瞬时风压分布为基础,计算大跨度空间结构等效静风荷载的基本方法。首先利用广义坐标合成法得到目标响应的时程,从中确定产生最大响应的时刻,再以该时刻的瞬时风压分布为基础,采用动力放大因子法或附加风振力法计算等效静风荷载。当采用附加风振力法将瞬时风压和附加风振力叠加时,可以得到与风压作用方向不同的等效静风荷载,避免了在某些情况下对风压的过度放大。为便于工程应用,根据精确的等效静风荷载计算式,将荷载中的准静态分量和附加风振力分离,提出了附加风振力的简化计算式。通过大型结构算例分析,证明采用上述方法可以给出合理的等效静风荷载分布,不但能够保证响应目标的等效,其他响应也符合真实情况。

An analysis method was proposed to derive the equivalent static wind load （ESWL） on the large-span spatial structures on the basis of the instantaneous wind pressure at specific time. The response time history was resolved firstly by generalized coordinates synthesis method and the time at which the response reaches its extreme was identified. As long as the dynamic amplification factor or the additional wind-induced vibration force was imposed on the instantaneous wind pressure at that time, the ESWL corresponding to the extreme response could be obtained accordingly. The combination of the instantaneous wind pressure and the additional wind-induced vibration force can result in a reasonable ESWL which acts along the different direction with the surface wind pressure and thus avoid overestimating the ESWL at some situations. Moreover for the convenience of the engineering application, the quasi-static component and additional wind-induced vibration force were thoroughly separated according to the accurate formula of the ESWL and the simplified estimation of the additional wind-induced vibration force was also proposed. The validity of the method was demonstrated by the case study on a large-span structure. Under the action of the ESWL derived by the method, the equivalence of the target response is achieved and other responses also agree with the actual responses.