根据预期减震目标,对总高度90.35m,高宽比达3.96,设防烈度为8度(0.2g)的玉溪公租房项目中基础隔震高层剪力墙结构,按照7度设防对上部结构进行设计,对其进行罕遇地震作用下静力弹塑性(Pushover)分析,并对隔震结构整体进行非线性时程分析。设计并制作了1:12.5的缩尺模型,对其进行振动台试验研究。结果表明:基础隔震高层剪力墙结构呈现出良好的抗震性能及较高的地震安全储备;在8度多遇、设防地震作用下,结构完好,前5阶频率基本未发生变化,结构尚处于弹性状态;在8度罕遇地震作用下,仅少数连梁轻微开裂;结构层间位移角、隔震支座最大位移、支座应力均未超过规范限值;隔震层滞回曲线饱满、耗能显著;在9度超罕遇地震(0.7g)作用下,未出现倾覆、局部倒塌现象,仅少数连梁、剪力墙出现轻微损伤,频率最大衰减幅度小于10%,刚度下降不明显。
The superstructure of Yuxi public rental buildings, which is base-isolated high-rise shear-wall structure with a height of 90.35 m, a height-width ratio of 3.96, and a seismic fortification intensity of 8 degree (0.2g) , was designed under 7 degree, according to the expected earthquake reduction target. The Pushover analysis under rare earthquake was done. Furthermore, the nonlinear earthquake time-history analysis on the entire isolated structure was also done. Then, a 1:12.5 scaled model was made according to similitude theory, and shaking table tests were carried out. The experimental investigation results show that the base-isolated high-rise shear-wall structure designed with the given method has excellent seismic performances and enough seismic safety margin. The structure is well without any failure, frequencies of the first 5 orders unchanged. The structure still remains elastic, under frequent and moderate earthquake of 8 degree. Tiny cracks appear on several coupling beams, under rare earthquake of 8 degree. The inter- story displacement angle, the maximum displacement as well as the stress of rubber bearings completely match the requirement of the code. The horizontal shear force-displacement hysteretic loops of isolation story are full, which shows a significant dissipation of seismic energy. After suffering from the super rare earthquakes of 9 degree (0.7g), the structure has not overturned, and local collapse has not occurred. A few coupling beams and walls are damaged slightly, and the maximum decrease of the first 5 order frequencies has been smaller than 10%, which means the decrease of the structure' s stiffness is negligible.