预应力对柱支承球面扁网壳非线性稳定的影响

Effect of prestressing on nonlinear stability of column-supported steel lattice shallow shell roofs

为研究预应力球面扁网壳结构性能,以"一次张拉二次加载"预应力设计为例,分析了通常设计的预应力及其引入位置对一类柱支承双层球面扁网壳非线性稳定的影响。为了与张拉时扁网壳支座设计情况相符,编写了计算程序。通过对扁网壳具有不同矢跨比和不同布索方案的设计工程的分析,发现预应力可以适当提高屈曲荷载,但提高幅度不大。当预张力相同时沿拉力环域布索的屈曲荷载提高幅度比在扁网壳支座间布索大。预应力没有改变结构的屈曲特征,对荷载位移平衡路径影响也有限。要较大幅度提高这类结构的屈曲荷载只能采取其它途径。

The effect of prestressing on the nonlinear stability of a columnsupported steel lattice shallow spherical shell was investigated based on a single tensiondouble loading prestressing. A program was developed to analyze the changes of the shell bearing from the construction stage to the normal working stage. The structure stability was studied for different risetospan ratios and with different string layout schemes. The results show that prestressing can increase the buckling load, but the increase is limited. With the same prestressing force, the critical structural load is large when the strings are laid along tension stress trajectories, but the critical structural load is less when the strings are laid between adjacent shell bearings. Prestressing does not change the buckling mode and does not cause the loaddisplacement equilibrium path to significantly diverge from the original. Therefore, prestressing cannot significantly increase the critical structural load.