大跨屋盖结构风场重构及等效静力风荷载研究

Long-span roof structures are of different shapes and sizes, with the characteristics of light weight, large flexibility, small damping, closed natural frequencies and so on. The wind loading has become the dominated loading for structural design. Wind resistant theory of long-span roof structures is still in the exploratory and comparative stage, especially the wind pressure field reconstruction method, resonant response calculation method and the equivalent static wind loads calculation method need to be further improved..The proposed project focuses to the key issues unsolved on wind resistant theory of long-span roof structures by the wind tunnel tests and theory of random vibration. Firstly, according to the wind pressure distribution of long-span roof structures, the flow field is divided into separate area and attachment area, because the flow field in each area is more similar, the reconstruction is more accurate. Secondly, the wind-induced vibration is divided into background and resonance by the theory of random vibration analysis, an improved wind vibration calculation method will be proposed. Finally, a more effective universal equivalent static wind loads calculation method will be proposed by selecting the more effective basic vectors and improving the calculation model.

大跨屋盖结构体型各异，且具有质量轻、柔度大、阻尼小、振型密集等特点，使得风荷载成为了此类结构设计的控制性荷载。大跨屋盖结构的抗风分析理论仍处于探索、比较阶段，尤其是屋盖表面风场重构方法、共振响应计算方法以及多目标等效静力风荷载计算方法尚需进一步完善。. 本项目针对大跨屋盖结构抗风分析理论中存在的若干关键问题，通过风洞试验和随机振动理论分析相结合的方法开展研究。首先，根据大跨屋盖结构表面风压分布特征，将流场分为分离区和附着区，确定流场分区准则并研究分区风场重构方法，由于分区后各区域内的流场更为相似，重构将更为精确；其次，通过随机振动理论分析，将风振响应的计算分为背景响应和共振响应两部分，改进共振响应计算公式，进而提出一种优化的风振计算方法；最后，在以上分析基础上，选择更有效的基本向量，并改进计算模型，得出一种更为有效的多目标等效静力风荷载计算方法。

本项目通过随机振动理论分析、风洞动态测压试验和工程案例计算，研究了大跨屋盖结构风振响应和等效静力风荷载，概述如下：.结合非高斯分区划分标准和脉动风的相关性判定标准，得出了一种有效的大跨屋盖结构流场分区划分准则。根据大跨屋盖结构流场分区划分准则，得出了大跨屋盖结构分区风场重构计算方法。.提出了一种高效的大跨屋盖结构风振计算方法。背景响应采用拟静力方法计算得到，共振响应采用实用简化计算公式。该方法既保证了计算精度，也提高了计算效率。.建立了合理的数学计算模型，选取更为有效的基本向量，并对等效静力风荷载的值进行了有效的约束，得出了一种高效的大跨屋盖结构多目标等效静力风荷载计算方法。