8度区异形柱框架结构基础隔震研究

A study on a base isolation RC frame structure with specially shaped columns designed for seismic fortification intensity 8 zone

对抗震设防烈度8度(0.2g)、预期隔震目标降低一度的基础隔震异形柱框架结构的隔震性能展开研究。对比了异形柱框架结构和矩形柱框架结构的隔震设计,并对满足隔震设计目标的基础隔震异形柱框架结构开展振动台试验。结果表明异形柱框架结构抗侧移刚度的优势使其在隔震设计阶段能获得比同条件的等截面面积矩形柱框架更小的水平向减震系数;且基础隔震异形柱框架结构振动台试验的加速度和位移响应得到明显降低,实现了小震不坏,大震不倒的设防目标。验证了基础隔震是提升异形柱框架结构抗震性能的有效措施之一,但隔震设计应充分考虑上部结构的抗震性能劣势,适当限制其塑性性能的发展程度。总的来说,引入基础隔震技术能提升8度(0.2 g)区异形柱框架结构的抗震性能,其在高烈度地区具有良好的推广应用前景。

The isolation performance of a base seismic isolated RC frame structure with specially shaped columns designed for seismic fortification intensity 8(0.2 g)zone were investigated through numerical analyses and shaking table test.The base isolation design of RC frame structure with specially shaped columns was compared with that of a RC frame structure with common rectangular columns.A shaking table test was conducted on the model of base seismic isolated RC frame structure with specially shaped columns that satisfied the objective of base isolation design.Results show that the RC frame structure with specially shaped columns tends to have considerable lateral stiffness,which makes it have smaller horizontal seismic decrease coefficient than the RC frame structure with rectangular columns.In addition,the shaking table test shows that the acceleration and displacement responses of base seismic isolated RC frame structure with specially shaped columns are significantly reduced.That is to say,the seismic fortification objective,i.e.,buildings are neither damaged when subjected to frequently earthquake influence nor collapsed when subjected to rarely earthquake,has been achieved.Furthermore,the base isolation has been validated to be one of effective ways to enhance the seismic performance of the RC frame structure with specially shaped columns.It should be noted,however,that the weakness of the upper structure should be carefully considered in seismic isolation design,and the development of the plastic state should be constrained to a certain level.In sum,the seismic isolation technique can improve the seismic performance of the RC frame structure with specially shaped columns in seismic fortification intensity 8(0.2 g)zone,indicating the promising application in high intensity area.