考虑方向性和不确定性的大型屋盖围护结构体系多重风致响应概率分析及其抗风可靠性评价

It is well known that wind pressure on large roof has directionality and uncertainty, and wind pressures between different areas are also correlated. When evaluating the wind-resistant reliability of cladding system on the large roof, it is necessary to consider these characteristics based on probability analysis. At present, due to the lack of a theoretic framework to derive the joint probability of multiple wind effects considering the directionality, uncertainty and correlation of different wind effects, it is not clear about the effect without considering the above three factors on the wind resistant reliability of the large roof cladding system. In response to this problem, the project uses a combination of statistical and probability theory and wind tunnel tests to assess probabilistic multiple extreme responses and reliability analysis of cladding system on large roof structures with consideration of both uncertainty and directionality. The multi-variate extreme value model and the conditional probability form are used to propose the framework to derive joint probability distribution of multiple wind responses considering the directionality, uncertainty and correlation. Influence of directionality, uncertainty and correlation on wind-resistant reliability of cladding system are revealed by conducting wind tunnel tests under different terrain simulations. Based on the wind tunnel test results, the theoretical framework is simplified for fully correlated and independent assumptions, and the directionality factor and peak factors with consideration of correlation will be proposed for the design of the cladding system on large roof.

大型屋盖表面风压具有方向性和不确定性，且不同区域风压之间有相关性；基于概率分析同时考虑这些特性是合理评估大型屋盖围护结构体系抗风可靠性的前提。当前，由于尚缺乏同时考虑风效应方向性、不确定性和不同风效应之间相关性的概率分析框架，以上三个因素对大型屋盖围护结构体系抗风可靠性的影响尚不明确。针对此问题，本项目综合运用统计学与概率论理论和风洞试验，开展考虑方向性和不确定性的大型屋盖围护结构体系多重风致响应概率分析及其抗风可靠性评价研究。采用多元极值模型和条件概率形式提出考虑方向性、不确定性和风效应之间相关性的结构体系多重风致响应联合概率分布分析框架；通过风洞试验揭示不同来流条件下方向性、不确定性和相关性对大型屋盖表面不同位置处围护结构体系抗风可靠性的影响；基于风洞试验结果，对所提理论框架进行全相关和相互独立假设简化，提出适用大型屋盖围护结构体系的风向折减因子和考虑相关性的峰值因子等抗风设计方法。

本项目针对大型屋盖围护结构体系多重风致响应概率分析及抗风可靠性评价问题展开研究。研究了大型屋盖表面非高斯风压方向性、不确定性和相关性对屋盖风压极值确定的影响及定量评估方法，提出了非高斯风压系数极值估计的偏差和抽样误差计算新方法，阐明了不同基于矩的转换过程法对非高斯风压系数极值估计时偏差和抽样误差的区别。建立了考虑方向性和不确定性的多重风致响应概率分布分析理论框架，基于风洞试验，以鞍型屋盖为例研究了我国常见地貌条件下屋盖不同位置处围护结构的抗风可靠性特征。结合我国典型的大尺度稳态强风地区不同风向下极值风速的相关性特征，提出了我国大尺度稳态强风地区考虑建筑风荷载/效应极值方向性的新方法。本项目研究成果可为围护结构抗风设计、风灾保险提供理论支撑。