多点激励的高位隔震单层柱面网壳振动台试验

Shaking table experiment for high position seismically isolated single-layer latticed cylindrical shell under multi-support excitations

为研究单层柱面网壳结构橡胶支座隔震的效果以及地震动行波效应对隔震网壳地震响应的影响,采用高阻尼橡胶支座对网壳缩尺模型进行高位隔震,输入多组实际地震波进行振动台试验,包括一致激励及视波速1 000m/s、500 m/s和250m/s,测试结构的加速度、位移及杆件应变等动力响应。试验结果表明:HDR支座高位隔震有效延长大跨网壳结构的自振周期,上部结构所承受的总水平地震作用值降低烈度1~3度,隔震后上部结构的运动趋于同步。行波激励下,结构地震响应沿地震波传播方向相对逐渐增大,地震波传出端附近的隔震支座剪切变形明显增大,按一致激励设计偏于不安全。

In order to investigate the changes of earthquake responses in the single-layer cylindrical latticed shell following using the HDR（ high damping rubber）beatings, and the influences from earthquake wave-passage effect, a series of shaking table experiments of a single-layer cylindrical latticed shell shrunk model were conducted. The HDR bearings were installed at the top of the supporting columns. The visual wave velocity of earthquake records inputting to the structural model included infinite, 1 000 m/s, 500 m/s and 250 m/s. The dynamic responses such as acceleration, displacement and strain of members were examined. The results show that high-position seismic i- solation with HDR bearings could prolong the vibration period of latticed shell efficiently and reduce 1 to 3 degrees earthquake response of structure upon isolation layer. The latticed shell tends to produce whole motion following the application of the rubber beatings. The structural responses tend to be enlarged along the propagative direction of earthquake and the shear deformations of rubber beatings increase observably at the earthquake wave outlet under non-consistent excitation. Wave passage effect should be taken into account as consistent excitation may cause un- safe estimation.