隔震橡胶支座楼梯间模型结构振动台试验研究

Shaking table test of RC frame-staircase model with seismic isolation rubber supports

为检验梯段板下端设置隔震橡胶支座和聚四氟乙烯板滑动支座对现浇钢筋混凝土(RC)板式楼梯抗震性能的影响,以设置这两种支座的RC楼梯间框架结构单元为对象,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,观察其破坏过程,分析其遭遇不同水准地震作用时模型结构的自振频率变化、加速度反应、位移反应和破坏机制等。试验结果表明:梯段板下端设置隔震橡胶支座的楼梯单元具有良好的抗震性能,罕遇地震作用下破坏主要集中在框架结构中,有效地释放了梯段板的斜撑效应,实现了楼梯子结构迟于主体结构发生严重破坏的设计目标;采用聚四氟乙烯板滑动支座时,在共振破坏试验中梯段板出现剧烈的竖向翘起、左右晃动现象;采用隔震橡胶支座时,梯段板竖向加速度有所减小,且共振破坏试验中未出现晃动现象。

In order to verify the influence of seismic isolation rubber supports and polytetrafluoroethane plate sliding supports at the lower part of the stairway slabs on the seismic performance of cast-in-place reinforced concrete （RC） slab-stairs, the shaking table test of a 1/3 scaled RC staircase frame unit model structure was conducted to observe the failure process, and to analyze the natural vibration frequency variation, acceleration response, displacement response and failure mechanism by inputting motions of different intensities. Experimental results indicate that staircase unit with seismic isolation rubber supports at the lower part of the stairway slabs has excellent seismic performance and the failure is concentrated at main structure under rare earthquake input, which releases bracing effect of the stairway slabs effectively and realizes that substructure fails seriously later than main structure. When ploytetrafluoroethene plate sliding support is used at the lower part of the stairway slabs, severe vertical deformation and horizontal sway occur in the resonance destruction test. However, when seismic isolation rubber support is used at the lower part of the stairway slabs, vertical acceleration of staircase slabs is decreased, no sway occurs in the resonance destruction test.