摘要
研究长周期地震动对广州塔TMD体系的影响及结构响应的时频分布规律。对国内现行规范反应谱长周期段进行延长,选取7条地震动时程记录,并补充7条长周期地震动时程记录作为输入样本,研究不同周期的强震激励对超高耸结构TMD体系的影响。研究表明,长周期成分的地震激励显著增加了超高耸结构的响应,卓越周期在2.341 s至6.425 s的长周期地震动输入,比卓越周期低于1 s的短周期地震动输入,平均使结构桅杆顶的位移峰值与均方根值分别放大125.49%和91.63%;最优参数设计的TMD对短周期、长周期地震响应均起减震控制作用,对8度长周期大震下主塔顶和桅杆顶的位移峰值控制降幅分别达到28.61%和42.69%,对相应的位移时程响应均方根值的控制降幅分别达到32.56%和44.20%, TMD体系的减震控制性能对地震动卓越周期具有一定鲁棒性;对结构弱轴向的地震响应时程进行数值小波功率谱分析,结果表明:由于一般长周期地震动的卓越周期更接近广州塔结构弱轴向的二阶周期(2.888 s),不仅增加了一阶振型的响应,更显著加剧了以二阶振型为主的桅杆鞭梢效应, TMD对该效应一定程度上起了抑制作用;建议对周期大于6 s的超高耸结构TMD体系,在按规范反应谱选取地震动之外,应注意考虑长周期地震动的影响,以更全面评估结构性能。
The present paper studies the effect of long-period ground motion on the TMD system of Canton Tower, as well as the distribution of its time-frequency response. The paper lengthened the long-period part of the current specification response spectrum of China Code for selection of seven seismic records. Seven more long-period seismic records were also added up as input samples to study the effect of different periods of strong earthquake excitation on super-slender building with TMD system. The results show that the long-period excitation significantly increases the seismic response of the super-slender structure. Compared to the short-period ground motions with predominant periods less than 1 s, the long-period ground motions with predominant periods from 2.341 s to 6.425 s, enlarged the peak value and the root-mean-square of the displacement time histories respectively of the mast top respectively by 125.49% and 91.63%. Under 8-degree long-period earthquakes, the optimized TMD can suppress both short-period and long-period seismic responses. The TMD system enables reductions of peak displacement responses at the main tower top and the mast top respectively in28.61% and 42.69%, enables reductions of root-mean-square of the root-mean-square displacement response at the main tower top and the mast top respectively in 32.56% and 44.20%, so the vibration control performance of TMD system has certain robustness to the predominant period of ground motion. The results of numerical wavelet power spectrum analysis on the seismic response time history of the key parts of the structure show that the TMD control on the first-order vibration mode is effective. Moreover, because many long-period predominant periods recorded are closer to the second-order period( 2.932 s) in the weak axial direction of Guangzhou tower structure, the whipping effect of mast dominated by this mode is significantly intensified, and TMD also inhibits the effect to a certain extent. It is suggested that the seismic performance of the TMD system of long-period structures with period longer than 6 s, should be comprehensively evaluated by selecting different periods of ground motions.
作者
钱志超
陈洋洋
谭平
QIAN Zhichao;CHEN Yangyang;TAN Ping(Earthquake Engineering Research &Test Center,Guangzhou University,Guangzhou 510405,China;Guangdong Provincial Key Laboratory of Earthquake Engineering and Applied Technology,Guangzhou 510405,China;Key Laboratory of Earthquake Resistance,Earthquake Mitigation and Structural Safety,Ministry of Education,Guangzhou 510405,China)
出处
《华南地震》
2018年第4期96-104,共9页
South China Journal of Seismology
基金
"广东特支计划"科技创新领军人才(2014TX01C141)
广州市"珠江科技新星"(201610010159)
广东省自然科学基金(2016A030313544)
广东省教育厅创新团队项目(2016KCXTD016)
关键词
长周期地震动
广州塔
调谐质量阻尼器
小波变换
Long-period ground motion
Guangzhou tower
Tuned mass damper
Wavelet transform
