施工偏差随机分布对弦支穹顶结构整体稳定性影响的研究

基于概率理论,提出了适合于具有初始几何缺陷的弦支穹顶结构整体稳定性分析的施工偏差概率法,根据施工现场的误差分布特点,引入初始几何缺陷的随机分布形式,通过计算随机有限元模型,得到稳定系数样本值,并经过统计分析最终获得了具有一定可靠性的非线性整体稳定系数。以跨度93m、矢跨比1/12的优化后的弦支穹顶结构为算例,进行了考虑初始几何缺陷的非线性稳定性分析,与传统的特征值屈曲模态法和无初始几何缺陷的结果进行了对比分析,分析表明施工偏差概率法能够充分展现初始几何缺陷对弦支穹顶结构稳定性的影响,其计算稳定承载力比传统的特征值屈曲模态法低30%左右。通过对比分析,对初始几何缺陷最大值采用1.645倍的施工偏差控制限值,初始几何缺陷形状和大小更加合理,稳定分析结果偏于安全。施工偏差概率法在2008奥运会羽毛球馆弦支穹顶结构整体稳定分析中得到了良好的应用,验证了该方法的适用性。

Study on the influence of construction deviation random distribution on the integral stability of suspend-dome

This paper proposes a construction deviation probabilistic method that fits the integral stability analysis of suspend-dome structure with initial geometrical defects.According to the deviation layout of the construction site,the probabilistic distribution of initial geometrical defects is introduced,the sample space is worked out by computing the random finite element model,and the stability factor is gotten through analysis of these samples.With an optimized suspend-dome structure model whose span is 93m,rise-span is 1/12,the influence of initial geometry defects on the nonlinear integral stability is analyzed.Through comparison with the result drawn from the traditional eigenvalue buckling method,the nonlinear integral stability factor drawn from construction deviation probabilistic method is lower than that of traditional eigenvalue buckling method by about 30%.With the initial geometrical defect taken into account,the max value of the initial geometrical defects is adopted as 1.645 times of the construction control deviation,and this initial geometrical defect is more reasonable and safe.The construction deviation probabilistic method is successfully adopted in the stability analysis of the badminton gymnasium for 2008 Olympic Games,and the applicability of this method is verified.