混凝土折板式拟球面网壳的几何非线性分析  

Geometrically nonlinear analysis of concrete folded-plate-type quasi-spherical reticulated shell

作　　者：胡茂狄 张华刚[1,2] 马克俭 HU Mao-di;ZHANG Hua-gang;MA Ke-jian(Space Structures Research Center,Guizhou University,Guiyang 550003,China;Guizhou Key Laboratory of Structural Engineering,Gaizhou University,Guiyang 550003,China)

机构地区：[1]贵州大学空间结构研究中心,贵州贵阳550003 [2]贵州大学贵州省结构工程重点实验室,贵州贵阳550003

出　　处：《空间结构》2022年第4期38-47,共10页Spatial Structures

基　　金：国家自然科学基金项目(51568012);贵州省科学技术基金项目(黔科合J字[2008]2112号)

摘　　要：混凝土折板式拟球面网壳是通过面切割球壳再网格化而成.混凝土折算厚度较小,稳定问题可能成为工程应用的控制因素.采用有限元法进行几何非线性全过程分析,讨论了主要参数对非线性稳定性的影响,并拟合临界承载力公式.结果表明:非线性屈曲为跃越屈曲并在密肋平板形成薄弱区,结构的屈曲位移约为跨度的1/47;结构的矢跨比应控制在1/7.5~1/5之间,提高矢跨比可增大结构的刚度;支座环梁刚度对结构非线性稳定性的影响很小,建议支座环梁高度不小于跨度的1/60;脊梁刚度对临界荷载影响较大;不宜采用过大的密肋梁刚度以避免过多增加结构自重,密肋梁截面高度宜控制在跨度的1/240~1/120之间;与密肋梁类似,不建议采用过厚的屋面板;初始几何缺陷会导致结构临界荷载减小,结构的最大初始缺陷可按跨度的1/300采用.本文拟合的非线性临界荷载近似计算公式可用于估计结构的几何非线性稳定承载力.The concrete folded-plate-type quasi-spherical reticulated shell is formed by surface cutting spherical shell and then meshing.Due to the small thickness for concrete,the stability problem may become the control factor for engineering application.In this paper,the finite element method is used to carry out whole process analysis accounting for geometric nonlinearity.The influence of main parameters on nonlinear stability is discussed,and the formula of critical bearing capacity is fitted.The results show that the nonlinear buckling is snap-through buckling and forms a weak area in the multi ribbed plate,and the buckling displacement of the structure is about 1/47 of the span.The rise span ratio of the structure should be controlled between 1/7.5~1/5,and the stiffness of the structure can be increased by increasing the rise span ratio.The stiffness of the support ring beam has minor influence on the nonlinear stability of the structure.It is suggested that the height of the support ring beam should not be less than 1/60 of the span.The influence of the ridge beam stiffness is significant.It is not suitable to use excessive rigidity of multi ribbed beam,which leads to increasement of structural self-weight.The section height of multi ribbed beam should be controlled between 1/240~1/120 of the span.Similar to multi ribbed beam,the roof slab should not be too thick.The initial geometric imperfection will reduce the critical load of the structure,and the maximum initial imperfection of the structure can be used as 1/300 of the span.The approximate formula for the nonlinear critical load fitted in this paper can be used to estimate the geometrically nonlinear stability bearing capacity of the structure.

关 键 词：混凝土折板式拟球面网壳 几何非线性稳定 临界荷载 参数化分析 有限元法 

分 类 号：TU399[建筑科学—结构工程]