阶梯式椭圆抛物面网壳结构的整体稳定分析

RESEARCH ON OVERALL STABILITY OF STEPPED ELLIPTICAL PARABOLOID LATTICED SHELL

某体育馆屋盖结构采用阶梯式椭圆抛物面网壳,网壳形式为双层凯威特式。通过静力计算发现,网壳的受力状态有其自身的特点:上层网壳的下弦与下层网壳的上弦位于连续的同一壳面,力的传递是从作为下弦杆件受拉到作为上弦杆件受压的渐变过程。通过线性和非线性屈曲分析,对网壳结构的整体稳定性能进行研究。网壳结构在到达临界点前,已经有部分杆件进入塑性,但网壳结构仍然有继续承载的能力。网壳结构的弹塑性失稳过程从网壳长跨方向在结构前部的两处变阶位置的搭接节间弦杆开始。这些杆件的屈服导致其丧失承载进一步荷载增量的能力,造成相应节点发生内陷,进而导致整个结构发生失稳。

One stadium roof structure consists of ladder-type elliptical paraboloid latticed shell with the form of double-layer Kewitte.The members of lower chord in the top layer keep continuous with the members of upper chord in the bottom layer.The state of these members turned from tension into press in the process of force transmission.It was studied the overall stability using linear and nonlinear buckling analyses.Some members of the shell had turned into plastic state before the critical point of buckling.But the structure still remained the carrying capacity simultaneously.The elastic-plasticity buckling began from the members of the overlap between the top layer and the bottom layer of the shell.The yield members lost the carrying capacity for load increment,which led to the overall buckling.