框架结构中折板楼梯的抗震性能分析

Analysis on Seismic Performance of Folded-slab Stair

通过ANSYS数值模拟,对比了纯框架结构、带直板楼梯或带折板楼梯框架结构的振动特性.建议框架的楼梯设计尽量采用折板楼梯,并且使平台板与框架柱不连接或弱连接.这样可以削弱楼梯在水平地震作用下的"斜撑"效应,减弱楼梯参与整体结构受力的性能,减轻地震作用在框架间分配不均的现象,进而减小楼梯构件内力及其设计难度,并且使楼梯间的框架柱不再会形成短柱,同时降低位移限值的保守度,减少浪费.通过大量数据寻找出应力的变化规律,给出折板楼梯设计时需要的一些尺寸的建议值.

A comparative study was made of the vibration performances of frame structures without stair tread,with straight stair tread or with folded stair tread by ANSYS numerical simulation.The stair with folded slab was proposed to adopt while designing stair in frame structure.Landing board and frame column were proposed to be separated as well.With the method,the K-effect of stairs during earthquake would be weakened and the stairs＇ capability to take part in the whole structure decreases,too.The mal-distribution of seismic force among frames would be lightened.As a result,the internal force of the stair components and the difficulty of design would diminish.However,frame columns would not be changed into short columns.Meanwhile,the conservative degree of allowable value of drift angle would be reduced.Based on a lot of data,the variation law of stress was investigated,and proposals on dimensions of folded stair were put forward.