董石麟    陈兴刚
    （浙江大学空间结构研究中心  杭州 310027）

[提要]  鸟巢形国家体育场是2008年北京奥运会的中标方案，其屋盖主体结构实际上是由两向不规则斜交的平面桁架系组成的椭圆平面网架结构，每榀桁架与内环相切或接近相切，不妨称其为鸟巢形网架。通过研究和分析圆形平面的鸟巢形网架，其结构构形可简化成由统一的一类平面桁架系组成。对于周边简支的圆形鸟巢形网架，提出了简化计算法和相应的计算公式，可以方便地计算网架各杆件的内力和节点挠度。对于特定参数的鸟巢形网架，还给出了内力计算用表，以利工程利用。
[关键词]  鸟巢形  网架  构形  平面桁架  受力特性  简化计算方法

The bird-nest-patterned stadium is the successful bid scheme for 2008 0lympic Games in Beijing. The major structure of its roof is an elliptic plane grid structure which consists of several plane trusses irregularly crossed in two directions. Each truss is tangential or tangential approximately to the internal ring. It is thus named as a bird-nest-patterned grid structure.A circular bird-nest-patterned grid structure consisting of some identical plane trusses is first investigated in the aspects of form and load behavior. Then the simplified calculation method for such structures with simple supported boundary condition is proposed. Using the simplified method and derived formula, the internal force of each bar and displacement of each node can be obtained conveniently. The paper also gives out some internal force tables of structures with certain parameters, which can be directly usecl in the designing of this kind of structures.
Keywords: bird-nest-patterned; grid structure; form; load behavior; simplified calculation method