准静力补偿技术在大跨度屋盖结构风致响应计算中的应用

APPLICATION OF A QUASI-STATIC COMPENSATION TECHNIQUE IN CALCULATION OF WIND-INDUCED RESPONSE OF LONG SPAN ROOF STRUCTURES

大跨度屋盖结构因跨度大、质量轻等特点对风荷载较为敏感,风荷载通常是结构设计的控制荷载。该类结构风致响应计算表现出多模态参与以及模态耦合项不能忽略的特点,采用传统模态叠加法截取模态数多导致计算繁琐,因此需要研究一些精确而高效的方法。将准静力补偿技术应用于风致响应分析中,块里兹向量法在前处理阶段考虑脉动风荷载的空间分布特点,生成的初始向量为脉动风荷载空间分布模式的静力响应,保证生成的向量都对响应有贡献,而模态加速度法在后处理阶段采用准静力补偿理论补偿被忽略的高阶模态带来的误差,基于准静力补偿技术建立上述两方法之间的紧密联系。借助风洞试验同步测量的风压数据,以0.1矢跨比单层球面网壳结构为例进行风致响应计算,通过对比分析验证准静力补偿技术有效性。

Due to features of long span and light weight,a large span roof structure is relatively sensitive to wind load which is usually the dominant load in structural design.The calculation of wind-induced response is characterized by multi-mode participation and modal coupling terms which cannot be omitted.The application of the traditional mode-superposition to include many modes often inevitably leads to tedious calculations.Therefore,more accurate and highly efficient methods to compute wind-induced response are needed.A quasi-static compensation technique can be employed in dynamic wind-induced response analysis of a long span roof structure.In the pre-processing,the spatial characteristics of fluctuating wind load are taken into account in the block Ritz method which enables the initial Ritz vector to be a static response to spatial modes of the fluctuating wind load and ensures each formed vector to devote a contribution to the response.During the post-processing,the quasi-static compensation technique is used in the modal acceleration method to compensate the truncated errors due to ignoring the higher order modes.Based on the quasi-static compensation technique,the close connection between the block Ritz vector method and the modal acceleration method is established.With the wind pressure data measured simultaneously in wind tunnel tests and using a single-layer latticed dome with the rise-span ratio of 0.1 as an example,the wind-induced responses are computed and the efficiency of the quasi-static compensation technique is verified by comparison and analysis.