拱支撑双向柱面组合薄壳结构的稳定性分析

Stability analysis on a bi-directional cylindrical thin-shell structure supported by arches

东南大学九龙湖校区新建游泳馆的屋面采用了拱支撑双向柱面组合薄壳结构形式,本文对此结构进行了特征值屈曲分析及非线性稳定性分析,并研究了初始缺陷幅值、屋面壳板厚度和支撑拱矢跨比等参数对结构非线性稳定性的影响.研究表明,实际工程范围内的初始几何缺陷幅值对该拱支撑双向柱面组合薄壳结构的稳定性几乎没有影响;屋面壳板厚度的增加会加大屋面恒载,当未改变支撑拱的截面尺寸和配筋时会导致结构的稳定承载力系数降低,设计时应考虑采用较小厚度的屋面板或使用轻质高强的混凝土材料;采用增大支撑拱矢跨比的方式可提高结构的稳定承载力,但同时也增加了结构的混凝土用量,建议设计时结合工程实际要求选择合适的拱形参数.

A form of bi-directional cylindrical thin-shell structure supported by arches was adopted in the roof of the newly built natatorium in the Jiulong Lake Campus of Southeast University.In this paper,eigenvalue buckling analysis and nonlinear stability analysis were carried out for this structure.Effects of initial imperfection amplitudes,the thickness of roof shells and the rise-span ratio of supporting arches on the nonlinear stability of the structure were discussed.The results show that the initial geometric imperfection amplitude within a practical engineering range have minor influence on the stability of the structure,and the initial geometric imperfection can be ignored in such general analysis.The increase of roof shell thickness will add constant load to the roof.It can also reduce the stability bearing capacity coefficient of the structure if the section size and reinforcement of the arches are not changed.As a result,the use of thinner roof shells and lighter concrete materials with high strength should be considered to meet the design requirements.By increasing the rise-span ratio,the stability bearing capacity of the structure can be improved,but the concrete consumption can also be increased.It is suggested that appropriate arch parameters should be selected according to the actual requirements of the project.