摘要
近、远场长周期地震动中的长周期和近场脉冲特性的存在,可能导致长周期的高层隔震结构产生隔震层位移放大效应。通过振动台试验分析与验证其对长周期的高层隔震结构减震性能带来的不利影响,首先分析近、远场长周期地震动的反应谱特性;接着设计制作一个具有典型工程意义的大底盘单塔楼缩尺模型,进行有限元分析与振动台试验,探讨长周期地震动对楼层加速度、层间位移和隔震层位移等减震性能的影响;最后针对可能出现的隔震层位移超限问题,提出在隔震层增设黏滞阻尼器组成的复合减隔震体系,分析验证其减震和限位保护效果。结果表明:远场长周期地震动下隔震结构的响应明显大于普通周期地震动;近场脉冲长周期地震动作用下结构减震效果较差,隔震层位移明显大于位移容许值;复合减隔震体系有效地控制了隔震层的最大位移,降低了大底盘的加速度和层间位移响应,同时对上部塔楼也具有较好的减震效果。
Near-field and far-field long-period ground motions are featured by rich long-period components or near-field pulse components, which may result in the excessive deformation of the isolation layer. Its adverse influence on the seismic-reduction performance of the high-rise isolated structures should be revealed and validated by shaking table test. To this end, the re-sponse spectrum characteristics of near and far field ground motions are analyzed. Then, a single-tower steel frame structure with a large chassis is designed to form a typical test model. One-dimensional shaking table test and numerical simulation are performed. Also, the impacts of long-period ground motions on the seismic-reduction performance of story acceleration and in-terstory drift are investigated. Further, in view of the possible excessive displacement of the isolation layer, a combined seismic mitigation and isolation system is proposed by adding viscous dampers on the isolation layer. The effectiveness of the seismic mitigation and the limit protection are analyzed and verified. The results show that when compared with the conventional ground motions, the response of isolated structures will be larger under the far-field long-period ground motions. When subjec-ted to near-field pulse long-period ground motions, the seismic-reduction effect of the structure get worse and the maximum displacement of isolation layer is far beyond the allowable displacement. Besides,the combined seismic mitigation and isolation system can effectively control the maximum drift of the isolation layer and reduces the acceleration and interstory drift response of the large chassis. It also have well seismic-reduction effect on the upper tower.
出处
《振动工程学报》
EI
CSCD
北大核心
2017年第5期806-816,共11页
Journal of Vibration Engineering
基金
国家自然科学基金资助项目(51678158)
关键词
长周期地震动
高层隔震结构
近场脉冲型地震动
复合减隔震
振动台试验
long-period ground motions
high-rise isolated structures
near-field pulse-like ground motions
combined seismic mitigation and isolation
shaking table test
