摘要:2010年上海世博轴屋面体系由索膜结构和6个阳光谷钢结构组成，其中阳光谷为自由曲面单层网壳结构。由于阳光谷体量大、杆件截面尺寸小，具有网壳结构的典型特征，所以其稳定性是设计中关心的关键问题之一。本文对第一号阳光谷进行了整体稳定性分析研究。通过调整不同参数，研究了几何非线性、材料弹塑性及初始几何缺陷对结构整体稳定性的影响。分析结果表明，不同条件下结构的稳定承载力均满足国家相关规范要求；加载至第一个临界荷载时部分构件已经进入塑性，表明结构的失稳破坏后于强度破坏。本文采用的方法和研究内容可为类似工程的分析与设计提供参考。

Abstract: The project Expo Axis is a landmark building of Expo Shanghai 2010. Its roof system is composed of a cable-membrane structure and six free-form single-layer latticed shells named Sun Valley. Sun Valleys are different in shape and size and provide eighteen support points for cable-membrane structure. Because there is no clause used for free-form structure in current codes and specifications, it is difficult to carry on stability analysis for Sun Valleys. The Sun Valley NO.1 is studied for overall stability analysis in the paper. Ninety three load combinations are used in the process of buckling analysis, and D+0.7×L2+W315 is selected as control load for nonlinear overall stability analysis. And then with different initial conditions considered the influence of geometric nonlinearity, plastic properties of material and initial geometric imperfection on overall stability of the structure are researched. The results show that the stability load factor of structure can meet the relevant specifications of China in every condition. Some members enter the plastic state when first critical load is reached, so the structure will enter strength failure before overall unstable failure happen. The outputs of the study will provide useful reference for design and analysis of other free-form projects.