考虑楼梯协同作用的框架结构抗震性能分析

Analysis of Seismic Performance of Frame Structure with Coupled Effect of Its Stairs

为研究在规范反应谱工况下,主体结构与楼梯协同作用时结构动力特性及内力变化规律。利用ETABS建立了3组初始振动模态不同的框架结构模型,研究楼梯对具有不同初始振动特性框架结构的影响。研究结果表明楼梯参与结构整体计算后,结构振型的次序可能会发生改变,同时结构初始刚度越小,结构自振周期减小幅度越大;通过分析3组模型在X、Y向反应谱工况下,楼梯对结构的楼层位移、层刚度及层间位移角的影响,得出3组结构模型的楼层位移、层刚度及层间位移角变化率随楼层的变化规律;分析楼梯参与结构整体计算对框架柱内力的影响,表明楼梯区格间的框架柱轴力增大较为明显而弯矩、剪力变化较小。

In order to research the effects of dynamic characteristics that the stair on main structure,three computer frame-structure models of different initial vibration mode are made.The results show that the order of the models may be changed and the smaller the lateral stiffness,the great decrease of the natural periods.The floor displacement,inter-story drift angle and story stiffness are also changed in same degree considering the coupled effect of the stair.Under the earthquake case,stairs coupled with primary structure have greater effect on the axis force and smaller effect on the shear force and moment of columns near to the stairs.