实时往复大变形下铅芯橡胶隔震支座力学性能试验研究

针对铅芯橡胶隔震支座在大变形多次实时往复荷载下力学性能退化问题，采用足尺铅芯橡胶隔震支座，通过高速压剪试验设备，对铅芯橡胶隔震支座进行了基本竖向力学性能试验、基本水平力学性能试验、多次不同大变形下实时加载水平力学性能试验，试验结果显示：铅芯橡胶隔震支座在实时往复多次大变形下，随着加载圈数的增加，隔震支座屈服力急剧下降，支座耗能能力降低，到试验结束时屈服力平均下降46.1%，加载圈数对屈服后刚度影响相对较小；实时往复大变形下测得的铅芯橡胶隔震支座屈服力在第2圈以后均小于采用国家标准试验方法得到的屈服力，试验结束时屈服力小于国家标准测到屈服力的43.8%，国家标准试验方法测得的屈服力与实际地震下铅芯橡胶隔震支座的屈服力相比偏小；铅芯橡胶隔震支座实时多次往复变形对其竖向刚度基本没有影响；铅芯橡胶隔震支座在实时往复大变形试验时其力学性能退化，静置一段时间后，其性能基本又恢复到实时往复大变形试验前的状态。

Experimental study on mechanical performance of lead rubber bearings under real-time reciprocating large deformation

Aimed to the degradation of mechanical properties of Lead Rubber Bearings (LRB) under real-time large-deformation reciprocating loads, the basic vertical mechanics performance test, the basic horizontal mechanics properties test and the horizontal mechanical properties tests under real-time large-deformation reciprocating loads of a full-scale lead-rubber bearing were carried out by high-speed compression-shear test equipment. The experimental results show that with the increases of number of loading cycle under real-time large-deformation reciprocating loads, the yield strength and energy dissipation capacity of the LRB abruptly decreases. At the end of the test, the yield strength of LRB decreases by 46.1% on average, and the number of loading cycle has a relatively small effect on the post-yield stiffness. The yield strength of LRB obtained after second loading cycle under real-time large-deformation reciprocating loads is all less than yield strength measured by testing method of national standard and the yield strength at the last loading cycle under real-time large-deformation reciprocating loads is less 43.8% than that measured by the national standard. The yield strength of LRB obtained by the test method of national standard is smaller than that of LRB under actual earthquakes. The real-time reciprocating large deformation has no effect on the vertical stiffness. Mechanical performance of LRB degrades under real-time large-deformation reciprocating loads, however, after an interval of time, mechanical performance of LRB return back to the state before real-time large-deformation reciprocating loads.