圆形五边形三四撑杆混合型开口索穹顶预应力态及多参数敏感度分析

ANALYSIS OF PRESTRESSING MODE AND MULTI-PARAMETER SENSITIVITY OF CIRCULAR PENTAGONAL THREE-FOUR-STRUT ALTERNATED CABLE DOME WITH INNER HOLE

  • 摘要: 五边形三四撑杆混合型索穹顶构形具有如下特点:首先是在上弦脊索处采用了任意等腰五边形的网格; 其次是有别于早期Fuller的传统张拉整体思想,改为在上下弦节点间设有多根倾斜的撑杆,这使得在上弦网格扩大的同时,也提高了整体结构的稳定性。根据节点平衡条件,提出了五边形三四撑杆混合型开口索穹顶结构预应力态的简捷分析方法,并给出其全套预应力态索杆内力一般性计算公式,可以方便地计算出精确解;围绕结构的下弦环索道数、矢跨比、厚跨比、下弦节点水平半径系数等参数计算了60个算例,分析研究了不同参数对索穹顶预张力分布的影响。多参数灵敏度分析结果表明,矢跨比对结构预张力分布影响较小,而预张力分布对厚跨比、下弦环索道数、下弦节点水平半径系数和上弦网格系数较为敏感,在进行结构设计时应着重考虑。本文的研究为索穹顶结构的选型和设计提供了新的方案。

     

    Abstract: The structural configuration of pentagonal three-four-strut alternated cable dome has the following characteristics: firstly, an arbitrary isosceles pentagonal grid is used at the ridge of upper chord; secondly, it is different from the traditional tension integral conception of Fuller, in which there are inclined multi-strut at the upper and lower chord nodes, which expands the upper chord grid and improves the stability of the overall structure. According to the joint equilibrium equation, a simple method for calculating the prestressing mode of pentagonal three-four-strut alternated cable dome is proposed with inner hole, and the general calculation formula of internal force of prestressed cable strut is derived. The formula calculation generates exact solutions. Calculations of 60 cases are carried out for different parameters of the structure, such as the number of lower chord ring cables, rise-span ratio, position of lower chord nodes and structural thickness adjustment coefficient, and the effects of different parameters on the pretension distribution of cable dome are discussed. The results of multi-parameter sensitivity analysis show that the prestressing distribution of the structure is not sensitive to the rise-to-span ratio, while the thickness-to-span ratio, the number of lower chord loops and the horizontal radius coefficient of the lower chord nodes have a greater influence and should be considered when designing the structure. The study of this paper provides a new scheme for the selection and design of cable dome.

     

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