蜂窝四撑杆型索穹顶的构形和预应力分析方法

Configuration and prestress distribution of honeycomb-type cable dome with four struts

提出了一种新型的蜂窝四撑杆型索穹顶,它的构形为索穹顶的上弦索是一种蜂窝形网格布置,下弦节点处设有四根撑杆,上弦节点处设有两根撑杆.改变了现有国内外工程应用和研究的索穹顶,如肋环型、葵花型、Kiewitt型、鸟巢型索穹顶的上弦为长矩形条或联方形的网格布设,也改变了上、下节点处只有一根竖向撑杆的特点.完全抛弃了Fuller构想拉索海洋与撑杆（压杆）孤岛的构形.这种蜂窝四撑杆索穹顶具有环索、斜索数量少,撑杆和整体结构稳定性好,施工张拉方便,造型丰富优美等诸多优点.文中还根据节点平衡方程,推导了蜂窝四撑杆型索穹顶预应力态索杆内力的一般性计算公式,对若干参数的索穹顶给出了索杆预应力的计算用表和对比分析,以了解索穹顶预应力态的分布规律和特性.本文研究为索穹顶的设计和选型提供了新形式、新思路.

This paper presents a new type of four-strut honeycomb-type cable dome,with its upper chords forming a honeycomb-shaped grid structure and four struts converging at the lower chord node,and half of that at the upper node.This new configuration significantly differs from the existing forms for practical applications and researches both at home and abroad,since traditional patterns including ribbed-,sunflower-,Kiewitt-and bird nest-type cable domes have long rectangular strips or diamond grids and only one vertical strut for both upper and lower nodes.When it discards Fuller’s idea that tensegrity is ocean of tensile cables and islands of compressed strut,this honeycomb-type achieves a much smaller number of hoop and oblique cables,and also have the advantages of better stability for struts and overall structure,easier construction process,rich and beautiful shapes and so on. Meanwhile,based on the nodal equilibrium equation,this paper also deduces the general calculation formula of its internal force,and gives an instant calculation table in terms of several usual parameters for cable dome structures.The prestressed state characteristics for honeycomb-type cable domes are obtained through comparative analysis.This study provides new forms and new ideas for the design of cable domes.