新型钢空腹夹层预应力组合扭网壳动力稳定性研究

Dynamic stability of new steel vierendeel sandwich prestressed composite twisted reticulated shell

以拟建60m跨度的钢空腹夹层预应力组合扭网壳为研究对象,对结构进行模态和地震作用下的动力性能分析.考虑了水平、竖向和组合地震作用对结构动力稳定性临界加速度的影响,结果表明:三种地震作用下的动力稳定性明显不同,弹性动力稳定性明显大于弹塑性.随着结构矢跨比的增大,结构的动力稳定性明显降低.增大钢空腹夹层板的肋截面尺寸可以显著提高结构的刚度,从而增大其动力稳定临界加速度.有阻尼比无阻尼时结构的动力稳定临界加速度增大了37.96%,故在计算结构动力稳定性时必须考虑.初始几何缺陷使地震作用下组合扭网壳结构的动力稳定性临界加速度显著降低,工程设计中应引起重视.预应力大小对扭网壳动力稳定性临界加速度影响较大,应根据结构跨度和屋盖高度等因素控制在一定范围内.

A 6Om-span steel vierendeel sandwich prestressed composite twisted reticulated shell is taken as the research object,and the dynamic performance of the structure under modal and seismic action is analyzed.Considering the influence of horizontal,vertical and combined earthquake action on the critical acceleration of structural dynamic stability,the results show that the dynamic stability under three kinds of earthquake action is obviously different,and the elastic dynamic stability is obviously greater than the elastic-plastic one.With the increase of rise span ratio,the dynamic stability of the structure decreases obviously.Increasing the rib section size of steel vierendeel sandwich plate can significantly improve the stiffness of the structure,thus increasing its dynamic stability critical acceleration.The critical acceleration of dynamic stability of the structure with damping ratio increases by 37.96%,so it must be considered when calculating the dynamic stability of the structure.The initial geometric imperfection significantly reduce the critical acceleration of dynamic stability of composite twisted reticulated shells under earthquake,which should be paid attention to in engineering design.The prestress has a great influence on the critical acceleration of dynamic stability,which should be controlled within a certain range according to the factors such as structural span and roof height.