环向折线形圆形平面网架的受力特性、简捷分析法与实用算表

Circumferentially folded circular plane grids:mechanical characteristics,simplified analysis method and practical calculation tables

环向折线形圆形平面网架是矩形平面单向折线形网架在圆形、圆环形建筑平面中的推广应用.通过结构构形研究和机动分析,论证了环向折线形圆形平面网架的基本结构体系是一种静定的空间桁架结构,提出了在轴对称荷载下基本结构体系的简化计算模型及其简捷分析法,推导求得了网架杆件内力的递推计算公式.为考虑与下部支承结构的协同工作,给出了弹性支承时的分析方法.对基本结构体系增设若干道环向杆件,可形成环向折线形圆形平面网架的加强结构体系,可提高结构的刚度、改善受力特性,根据相应的简化计算模型也可方便求得网架的杆件内力和节点位移.为方便工程设计应用,在常用轴对称荷载作用下,选取若干结构参数编制了环向折线形圆形平面网架基本结构体系的杆件内力实用算表.文中附有算例二则.

The circumferentially folded circular plane grid is an extensive application of the rectangular plane folded plate grid to circular or circular ring building planes. In this paper, the structural configuration study and kinematic analysis of the eircumferentially folded circular plane grid are carried out, and the basic structure is proved to be a kind of statically determinate space truss structure. A simplified structural calculation model of the basic structure under axially symmetrical load and the simplified analysis method are presented, and the recursion formulas for the internal forces of the grid members are established. The analysis method for the circumferentially folded circular plane grid with elastic supports is proposed, which can take the cooperative work between the grid and substructures into account. The reinforced structures of cireumferentially folded circular plane grid are formed by adding several series of circumferential members, which demonstrates higher stiffness and better mechanical properties than the basic structure. The internal forces and joint displacements of the reinforced structures can also be easily obtained from the simplified structural calculation model. Some practical calculation tables for the cireumferentially folded circular plane grid under axial symmetrical load are developed, which are based on the simplified analysis method and correspond to several structural parameters. These tables can help to improve the efficiency of the engineering design of the eircumferentially folded circular plane grid structure. Two examples are illustrated.