摘要
为了改善传统索穹顶结构的受力性能,该文提出了一种联方型双撑杆索穹顶结构,该索穹顶的上弦节点与两根斜撑杆相连,稳定性好并且便于张拉施工。针对联方型双撑杆索穹顶的找力分析问题,根据节点平衡方程,推导出考虑结构自重时索穹顶的预应力计算公式;给出了不同参数下联方型双撑杆索穹顶的预应力计算表,分析了该结构的受力特性;比较了考虑结构自重和不考虑结构自重时索穹顶初始预应力的差别,并采用有限元迭代法对比验证了理论公式的准确性。分析结果表明:随着矢跨比和撑杆高度的增大,结构中所有构件的初始预应力将减小;在自重荷载下,内圈脊索内力降低,最外圈斜索和环索内力显著增加;采用该文提出的理论公式可快速准确的获得考虑结构自重时联方型双撑杆索穹顶的实际预应力分布,为工程设计提供参考。
A type of Levy cable dome with double struts is presented to improve the mechanical behavior of cable domes. This structure has a good stability and is convenient for construction due to the fact that each upper node is connected to two inclined struts. To solve its force finding problem, according to the balanced equations of connections, the calculation formulas of prestress distribution with self-weight considered are deduced. The calculation tables of cable dome under different parameters are given to investigate the mechanical behavior. The differences of prestress-state with and without self-weight are compared, and the proposed formulas are checked using finite element iteration method. The results show that with the increase of rise-span ratio and height of struts, the initial prestress decreases for all components. Under self-weight, the internal force of inner ridge cables decreases, while the internal force of the most outer diagonal cables and hoop cables increases significantly. Using the formulas deduced in this paper, the actual initial prestress distribution considering self-weight for Levy cable dome with double struts can be obtained rapidly and accurately, providing a reference for engineering design.
引文
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