柱顶层间隔震体系增量动力响应研究

针对悬臂柱顶有拉梁和无拉梁层间隔震体系的抗震性能问题,运用增量动力分析(IDA)方法进行弹塑性分析,模拟结构从弹性到弹塑性直至最后倒塌的全过程。通过调幅地震动得到相应的层间位移角及峰值加速度,分别绘制单条与多条IDA曲线分析拉梁对隔震结构动力响应的影响,研究两种结构的抗震性能。结果表明:在相同性能点,有拉梁和无拉梁对纤维铰弯矩值和曲率值基本无影响,而在不同性能点,纤维铰状态明显不同;两种体系从正常使用阶段到防止倒塌阶段所需的加速度峰值的差距慢慢增大;在极罕遇地震下,柱顶有拉梁层间隔震体系的下部结构抗震性能要高于柱顶无拉梁层间隔震体系。

Incremental Dynamic Response of Inter-story Isolation System on Top of Columns

To study the seismic performance of inter-story isolation systems with and without a straining beam on the top of cantilever columns, we used the incremental dynamic analysis (IDA) method to simulate the whole process from elasticity to elasto-plasticity until structural collapse. We obtained the story drift ratio and peak acceleration by modulating the amplitude of the ground motions. We then plotted IDA curves to explore the influence of the straining beam on the dynamic response of the isolation structure and to study the seismic performances of the two structures. The results show that at the same performance point, the straining beam has no effect on the bending moment and curvature values of the fiber hinge, but at different performance points, the state of the fiber hinge is significantly different. The difference between the peak acceleration of the two systems increases from the normal-use state to the collapse-prevention state. When subjected to extremely rare earthquakes, the seismic performance of the sub-structure in the inter-story isolation system with a straining beam on top of the cantilever column is higher than that without a straining beam.