厚街体育馆大跨度椭圆抛物面弦支穹顶结构的非线性屈曲分析

Nonlinear buckling analysis of long-span elliptic paraboloid suspended dome structure for Houjie Gymnasium

厚街体育馆钢屋盖采用大跨度椭圆抛物面弦支穹顶结构,支座间净跨110m×80m,上部单层网壳矢高9.4m。分别以此结构与相应的单层网壳为分析对象,考虑几何非线性、初始几何缺陷及活载的半跨布置,对两类结构的非线性屈曲性能进行对比研究。在此基础上,进一步探讨初始几何缺陷分布模式及材料弹塑性对弦支穹顶稳定分析的影响。研究表明:弦支穹顶的稳定承载力明显高于相应的单层网壳;初始几何缺陷按最低阶屈曲模态分布时,稳定承载力系数并非最小;材料非线性对结构稳定性影响较大;一致缺陷模态法并不完全适用于结构的稳定分析。

A long-span elliptic paraboloid suspended dome structure, in which the clear span between supports is 110m × 80m and the rise of the upper single layer reticulated shell is 9.4m, is employed in the steel roof of Houjie Gymnasium. The nonlinear buckling behaviors of the structure and the corresponding single layer reticulated shell are investigated, respectively, by considering geometric nonlinearity, initial geometric imperfection and half-span distribution of live loads. Based on the study above, the influences of initial geometric imperfection distribution mode and material elastic-plasticity on the stability analysis of suspended dome are further discussed. The results show that the stability bearing capacity of suspended dome is remarkably higher than that of single layer reticulated shell. The coefficient of stability bearing capacity usually is not minimal when the initial geometric imperfection is distributed in the first-order buckling mode, and the material nonlinearity might have significant effect on the coefficient. The consistent mode imperfection method is not fully applicable to the stability analysis of the structure.