设置水平接地构件的掉层RC框架结构振动台试验研究

Shaking table test of RC frame structures supported by different elevation grounds with horizontal embedding members

在山地掉层结构的实际设计中是否应建议设置水平接地构件是一个具有争议的问题。基于岩质地基的前提,设计和制作设置水平接地楼盖与未设置水平接地楼盖的6层1/8掉层RC框架结构模型各一个并进行振动台试验。对两模型的试验宏观现象及频率、振型曲线、阻尼比、加速度响应、位移响应、扭转响应等进行对比研究。结果表明:水平接地构件的设置加强结构顺、横坡向的刚度,显著改变结构的振型曲线;水平接地构件所在楼层的加速度放大系数受到限制,且相邻下层的加速度放大系数随地震强度增加而增大;两模型顺、横坡向变形规律不同且水平接地构件的设置大大减弱结构的扭转效应;设置水平接地构件的模型整体破坏相对轻些,且未发生显著的损伤转移。

Whether horizontal embedding members should be suggested to be set for the structures supported by different elevation grounds or not is a controversial issue in actual design.On the assumption of rock ground, two 6-floor and 1/8-scaled RC frame structure models supported by different elevation grounds were designed with or without horizontal embedding members, respectively, and the shaking table tests were carried out.The test phenomena, natural frequency, mode curve of vibration, damping ratio, seismic acceleration response, displacement response and torsional response were comparatively analysed.The results show that the horizontal embedding members may enhance the stiffness of structure along the slope direction and in the cross-slope direction, and they may remarkably change the mode curves of vibration.The seismic acceleration response of the floor with horizontal embedding members is under restriction and the amplification factors of acceleration at the adjacent lower floor increases with the increase of earthquake intensity.The deformation rules of the two models along the slope direction and in the cross-slope direction are different, and the horizontal embedding members may greatly reduce the overall torsional response of the building structure.Generally, the overall failure degree of the model with horizontal embedding members is lower without remarkable transfer of damage.