自保护隔震支座力学性能试验研究

Experimental investigation on mechanical properties of self-protection isolation bearing

为解决传统隔震支座不具备自保护能力的问题,研发了一种自保护隔震支座,并对其工作机理进行了阐述。据该隔震支座在不同侧向荷载作用下的工作特点可将其分为两个工作阶段。根据隔震支座的自保护能力要求对支座滑移材料进行了摩擦性能测试及择优分析,并对本次设计的自保护隔震支座及传统隔震支座进行了力学性能试验,结果表明:自保护隔震支座比传统隔震支座的竖向刚度最大降低幅值为21.91%,但仍具有足够的竖向刚度承受上部荷载,且这种差异随着竖向面压的增大而逐渐减小;支座在第一工作阶段的水平剪切变形加载下未滑动,发挥与传统隔震支座相同的功效,其滞回特性表现为典型的双线性特点;在第二工作阶段的水平剪切变形加载下支座开始滑动并摩擦耗能,其滞回曲线呈现为三线型特征,虽然有一定的捏拢,但滞回曲线的包络面积仍比传统隔震支座增加约86%;自保护隔震支座在第一工作阶段随加载速率的增加,屈服力和屈服后刚度均有增加,对应包络曲线的面积也呈增大趋势,整体的滞回曲线仍和传统铅芯橡胶支座相似,呈现出典型的双线性特性;在"第二工作阶段"启动后随着加载速率的变大,自保护隔震支座在复位段的捏拢现象逐渐减轻且支座在滑移状态下的性能逐渐趋于稳定。通过对试验曲线进行参数识别发现自保护隔震支座的恢复力模型可以采用呈捏拢效应的Bonc-Wen模型进行模拟,且拟合曲线与试验曲线吻合较好。

This paper puts forward a self-protecting isolation bearing(SPIB)to solve the problem that the traditional isolation bearing does not have the ability of self-protection.Moreover,the mechanism is introduced.Under the different lateral loads,the SPIB possesses two work stages by different functions at different stages.The friction performance test and the optimal analysis of sliding material are carried out.The mechanical properties of SPIB and the traditional isolation bearing are tested.Research results show that the vertical stiffness of SPIB has a maximum reduction of 21.91%compared with the traditional isolation bearing and the SPIB still has the sufficient vertical stiffness to withstand the upper load.In addition,this difference gradually decreases with the increase of the vertical surface pressure.The SPIB does not slip under the horizontal shear deformation loading at the first work stage,which works the same as the traditional isolation bearing.Its hysteretic behavior is characterized by typical bilinear characteristics.In the second work stage,the SPIB starts to slide under the horizontal shear deformation load and the friction consumes energy.The hysteretic curve shows a three-line feature,whose area is still about 86%greater than that of the traditional isolation bearing although it has some kneading.With the increase of the loading rate,the yield force and post-yield stiffness of SPIB increase at the first work stage.Additionally,the area of the corresponding envelope curve also increases.The overall hysteretic curve is still similar to the traditional isolation bearing,showing a typical bilinear characteristic.After the start of second work stage,with the increase of the loading rate,the pinching phenomenon of SPIB in the reset section gradually decreases and the bearing’s performance in the sliding state gradually becomes stable.It is found that the resilience model of SPIB can be simulated by the Bonc-Wen model with the pinching effect by the parameter identification of the test curve.The fitting curve agrees well with the experimental curve.