高层隔震结构减震机理探讨
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摘要
从时域和频域两个角度分别研究了高层隔震结构的减震机理。采用Etabs软件建立了高层框剪隔震建筑模型和多层框架隔震建筑模型,输入单向地震波,提取隔震层的加速度时程,将其视为地震动,输入原抗震结构中。对比了两者隔震前后的加速度反应谱,发现无论是高层隔震结构还是多层隔震结构都存在多振型减震的作用,但在高层结构中,高阶振型反应谱加速度的减少量相对于第一阶振型反应谱加速度的减少量要大很多,而在多层结构中,高阶振型的减少量与第一阶振型差不多,使得多振型减震在高层结构当中的效应要远大于多层结构;对比两者隔震前后基底最大剪力的减震率,发现对于高层隔震结构,叠加上高阶振型后,基底最大剪力的减震率有较大的提高,而对于多层隔震结构,减震率变化不大。从以上两个方面可以说明,多层隔震结构的高阶振型减震效应很小,且以第一振型减震为主,而高层隔震结构存在较大的高阶振型减震的效应,从而产生了其多振型减震的效应。
Isolation mechanism of high-rise isolation structrue was investigated in domains of both time and frequency.With the aid of Etabs software,high-rise frame-shear isolation building model and multi-story frame isolation building model were established with the unidirectional seismic waves as inputs,and the time histories of isolation layer accelerations were calculated,which were then considered as seismic wave inputs into the original seismic structure.Comparing the acceleration response spectra of the two models with and without the isolation devices,it is found that high-rise isolation building and multi-story isolation building are both under the action of multi-vibration modes isolation,but the reduction of high-order vibration modes accelerations in response spectrum is much more than that of the first-order vibration mode for high-rise structure while the reduction of high-order vibration modes accelerations in response spectrum is almost the same as that of the first-order vibration mode for multi-story structure,which makes the multi-vibration modes isolation much more effective in high-rise isolation structure than in multi-story isolation structure.Comparing the isolation ratio of the largest base shear forces,with and without the isolation devices,it is found that the isolation ratio of the largest base shear force increases obviously with the superposition of the effect of high-order vibration modes for high-rise isolation structure,while the ratio has only little change for multi-story isolation structure.From the two aspects mentioned above it can be explained that the effectiveness of multi-vibration modes isolation for multi-story isolation structure is low and the isolation mechanism mainly emerges on the first-order vibration mode isolation,while the high-order vibration modes isolation for high-rise isolation structure is really effective,which leads to the multi-vibration modes isolation.
Isolation mechanism of high-rise isolation structrue was investigated in domains of both time and frequency.With the aid of Etabs software,high-rise frame-shear isolation building model and multi-story frame isolation building model were established with the unidirectional seismic waves as inputs,and the time histories of isolation layer accelerations were calculated,which were then considered as seismic wave inputs into the original seismic structure.Comparing the acceleration response spectra of the two models with and without the isolation devices,it is found that high-rise isolation building and multi-story isolation building are both under the action of multi-vibration modes isolation,but the reduction of high-order vibration modes accelerations in response spectrum is much more than that of the first-order vibration mode for high-rise structure while the reduction of high-order vibration modes accelerations in response spectrum is almost the same as that of the first-order vibration mode for multi-story structure,which makes the multi-vibration modes isolation much more effective in high-rise isolation structure than in multi-story isolation structure.Comparing the isolation ratio of the largest base shear forces,with and without the isolation devices,it is found that the isolation ratio of the largest base shear force increases obviously with the superposition of the effect of high-order vibration modes for high-rise isolation structure,while the ratio has only little change for multi-story isolation structure.From the two aspects mentioned above it can be explained that the effectiveness of multi-vibration modes isolation for multi-story isolation structure is low and the isolation mechanism mainly emerges on the first-order vibration mode isolation,while the high-order vibration modes isolation for high-rise isolation structure is really effective,which leads to the multi-vibration modes isolation.
引文
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[9]付伟庆,王焕定,丁琳,等.规则型高层隔震结构实用设计方法研究[J].哈尔滨工业大学学报,2007,(10):1542-1545.
[10]吕西林.高层建筑结构[M].武汉:武汉工业大学出版社,2000.
[2]日本建筑学会.隔震结构设计[M].刘文光译.北京:地震出版社,2006.
[3]刘文光,闫维明,霍达,等.塔型隔震结构多质点体系计算模型及振动台试验研究[J].土木工程学报,2003,36(5):64-70.
4]王铁英,王焕定,刘文光,等.大高宽比橡胶垫隔震结构振动台试验研究(1)[J].哈尔滨工业大学学报,2007,(2):2060-2064.
5]王铁英,王焕定,刘文光,等.大高宽比橡胶垫隔震结构振动台试验研究(2)[J].哈尔滨工业大学学报,2007,(2):196-200.
6]付伟庆,王焕定,刘文光,等.LRB隔震结构模型振动台试验研究(1)[J].哈尔滨工业大学学报,2007,39(2):201-205.
7]付伟庆,王焕定,刘文光,等.LRB隔震结构模型振动台试验研究(2)[J].哈尔滨工业大学学报,2007,39(4):521-524.
[8]刘文光,杨巧荣,周福霖.大高宽比隔震结构地震反应的实用分析方法[J].地震工程与工程振动,2004,(4):116-121.
[9]付伟庆,王焕定,丁琳,等.规则型高层隔震结构实用设计方法研究[J].哈尔滨工业大学学报,2007,(10):1542-1545.
[10]吕西林.高层建筑结构[M].武汉:武汉工业大学出版社,2000.
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