基于隔震支座的吊脚框架结构刚度调整及其抗震性能分析

Stiffness adjustment and seismic performance analysis of stilted frame structure based on isolation bearing

基础不等高嵌固导致吊脚框架结构底层柱间抗侧刚度不均匀,采用设置隔震支座来调整这类结构抗侧刚度不均匀性是一种新的思路。文章采用理论方法分析了基于隔震支座调整吊脚框架结构底层柱间抗侧刚度不均匀的有效性,设计了不同坡度的2个吊脚框架结构算例和对应的6个设置隔震支座的吊脚框架结构算例,通过结构振型分解反应谱法弹性分析和弹塑性时程分析,分析了8个算例结构的底层柱内剪力和弯矩分配、结构剪力和层间位移等地震响应特征,进一步探讨了隔震支座的合理选型和布置对调整该类结构柱间抗侧刚度不均匀的有效性。结果表明:合理的隔震支座布置可有效调整吊脚结构底层柱的抗侧刚度不均匀,显著减小吊脚框架结构底层短柱的剪力,避免吊脚短柱局部破坏;同时隔震支座的布置可以降低吊脚框架结构整体地震响应,并改善其扭转效应。

The uneven lateral stiffness between the bottom columns of the stilted frame structure is caused by the fixed foundation with different heights.It is a new idea to adjust the uneven lateral stiffness of this kind of structure by setting isolation bearings.In this paper,the effectiveness of adjusting the lateral stiffness non-uniformity between the bottom columns of the stilted frame structure based on the isolation support is analyzed theoretically.Two calculation examples of the stilted frame structure with different slopes and six corresponding calculation examples of the stilted frame structure with isolation support are designed.The seismic response characteristics of eight example structures,such as shear and moment distribution in the bottom column,structural shear and inter story displacement are analyzed through the method of elastic analysis and elastic-plastic time history analysis of the structural mode decomposition response spectrum,and the effectiveness of reasonable selection and layout of isolation bearing in adjusting the non-uniformity of lateral stiffness between columns of this kind of structure is further discussed.The results show that:The uneven lateral stiffness of the bottom column of the stilted structure can be adjusted effectively by the reasonable arrangement of isolation bearings,the shear force of the bottom short column of the stilted frame structure can be reduced significantly,and the local damage of the hanging foot short column can be avoided.At the same time,the overall seismic response of stilted frame structure can be reduced and its torsional effect can be improved by the arrangement of isolation bearings.