混凝土框架楼梯设置滑动支座的结构模型振动台试验研究

我国现行建筑抗震设计规范及标准设计图集对现浇钢筋混凝土板式楼梯提出了增设滑动支座的构造措施，为检验其有效性，以设置聚四氟乙烯板构成的滑动支座的混凝土框架楼梯间结构单元为对象，对缩尺比例为1∶3的模型结构进行了振动台试验，通过输入不同的地震波，考察其遭遇不同烈度水准地震作用下的抗震性能。试验结果表明：梯段板下端设置滑动支座的楼梯间结构单元具有良好的抗震性能，破坏主要集中在楼梯间的框架梁柱中，在强震作用下，楼梯构件（包括梯段板、平台板、梯梁和梯柱）本身未发生先于框架梁柱的破坏；聚四氟乙烯板构成的滑动支座作用很有效，梯段板下端沿输入动方向发生了期望的水平滑动位移；同时，此处也伴随出现值得注意的竖向翘起和落下的现象。

Shaking table test on structural model of concreteframe-staircase with sliding supports

A new measure, in which sliding supports are used between the staircases and the main structure, is proposed in the current code for seismic design of buildings. To experimentally verify the new measure, the shaking table test of a large scaled structural unit of concrete frame-staircase with sliding supports made of ploytetrafluoroethene (PTFE) plate was conducted to dynamically test its performance under input motions of different intensities. It shows that, with the sliding supports at the lower end of the stairway slabs, the seismic behavior of the structural unit of concrete frame-staircase is satisfactory; even subjected to very severe motions, serious damages happen mainly in the members of concrete frame and no serious failure occurs earlier than the frame in the staircase parts, including stairway slabs, platform, supporting beams and columns; the sliding support made of PTFE plate works effectively and, horizontally along the direction of the input motions, the lower ends of the stairway slabs can slide back and forth as expected; meanwhile, they also have repeated up and down movements there.