马鞍形边界刚性屋面椭球形索穹顶受力性能分析

Mechanical Analysis of Ellipsoid Cable Dome with Rigid Roof on a Saddle-Shaped Boundary

天津理工大学体育馆屋盖采用马鞍形边界刚性屋面椭球形索穹顶结构,本文以此为工程背景分析了屋盖在全跨均布荷载和半跨均布荷载下的受力特点,得到了位移和内力.考虑屋面系统后结构的刚度有较大提高,刚性屋面索穹顶结构设计中需要考虑屋面系统的作用.对预应力水平、水平支承刚度和撑杆高度进行了参数分析,结果表明:几何刚度对刚性屋面索穹顶整体刚度的影响小于对纯索穹顶的影响;撑杆高度对结构刚度的提高作用大于预应力水平的作用,实际工程中应优先采用提高撑杆高度的方式来提高结构刚度,在满足结构需求的条件下预应力应尽量小;边界刚度对索穹顶结构性能有较大影响,环梁边界的刚度无法达到3向铰接,结构的设计计算中应考虑弹性边界.

Ellipsoid cable dome with rigid roof was adopted in the gymnasium of Tianjin University of Technology,whose boundary is a saddle-shaped curve.Based on this project,the mechanical behavior of ellipsoid cable dome with rigid roof was studied in this paper.The displacement and internal force under full span and half span uniform loads were obtained.The stiffness of the structure is enhanced by roof and purlin system,therefore roof and purlin system should be considered in designing.Parametric analysis focusing on prestress level,horizontal supporting stiffness and length of strut was done.Their influence was then analyzed.The results show that the contribution of geometry stiffness to the overall stiffness of metal cladding cable dome is less than its contribution to pure cable dome structure;lengthening struts is more effective to increase geometry stiffness than amplifying prestress,hence,lengthening struts is prior to amplifying prestress in stiffening the structure,and prestress level should be as low as possible as long as the structural requirements are satisfied;the flexibility of boundary stiffness leads to great difference in structural behavior,and ring beam cannot constrain nodal displacement as hinge consumption,therefore flexible boundary should be taken into account in designing.