基于小波分析的基础隔震结构的抗震分析

发布时间：2018-04-17 21:52

本文选题：小波分解 + 基础隔震　；参考：《西安建筑科技大学》2015年硕士论文

【摘要】：本文利用小波分解的方法将5.12汶川地震动分解为相邻频带互不重叠的小波分量,然后将原波及其不同的小波分量作为地震动输入到基础隔震结构模型中,并与未隔震结构模型进行对比分析,得到地震波以及不同小波分量作用下对结构动力的影响。所做的主要工作及研究成果如下:1、从5.12汶川地震数据库中,分别选取距震中19 km的汶川卧龙地震波和距震中634km的陕西草滩地震波,并采用B-样条小波将其进行8次分解,得到9段紧相邻互不重叠的小波分量,以此作为基础隔震体系及未隔震体系时程分析所使用的输入地震波,并绘制出它们的加速度时程图以及对应的傅里叶谱图。2、本文研究表明:不论是在卧龙波不同频带、还是在草滩波不同频带作用下,不论隔震结构还是未隔震结构,同时包含结构基本频率和原波卓越频率的频段对结构的位移反应最大,其次是包含结构基本频率的频带对结构的位移反应也很大,包含有原波卓越频率的频带对结构的位移反应比前两个频带作用下的反应小,但是均大于其它频带作用下结构的位移反应。结构的等效静力也是如此。3、高频分量对结构位移的贡献很小,可以忽略高频分量对位移的影响,低频分量对位移的贡献很大,隔震结构各个楼层的位移几乎全由结构第一振型贡献,隔震结构的顶部总位移绝大部分是由基底位移贡献的,隔震结构的层间变形相比未隔震结构而言,大大减小。在长周期草滩波作用下隔震结构各个楼层的位移远远大于在短周期卧龙波作用下隔震结构的位移,说明长周期波对隔震结构更为不利。4、在卧龙波及其小波分量作用下,隔震结构各个楼层的等效静力远远小于未隔震结构各个楼层的等效静力,但是在草滩波作用下,隔震结构各个楼层的等效静力与未隔震结构各个楼层的等效静力相差不大,说明隔震结构在草滩波作用下的隔震效果不是那么明显。长周期草滩波高频带作用下未隔震结构各个楼层的等效静力明显小于短周期卧龙波高频带作用下未隔震结构各个楼层的等效静力。在高频分量作用下,隔震结构的等效静力远远小于未隔震结构的等效静力,可以认为隔震层相当于一个软弱的地基,起到一个低通滤波器的作用,大大滤去了地震波的一些高频分量。5、不论是在长周期草滩波还是在短周期卧龙波作用下,低阶振型对结构各个楼层的等效静力起到主导作用。隔震结构在第一、第二阶振型下各楼层的等效静力所占的比重最大,在3.13Hz以下频带,第一振型所占的比重大于第二振型的比重,3.13Hz以上的频带,由于激发了高阶振型的作用,导致第一振型所占的比重减少。6、在草滩波、卧龙波及其相应不同频带作用下,隔震结构隔震层的剪力VA0与上部结构的基底剪力VA1大致相等,楼A隔震层的剪力要稍稍大于上部结构的基底剪力,但在某些频带会出现反常,在6.25~12.5Hz频带内,出现VA0小于VA1,3.13~6.25Hz频带也出现这种情况。
[Abstract]:In this paper, using the method of wavelet decomposition of the 5.12 Wenchuan earthquake are decomposed into wavelet components of adjacent bands do not overlap each other, then the original wave and different wavelet components as seismic input to the model of base isolation structure, and the results are compared with the non isolated structure model, the influence on the power structure of the seismic wave and different wavelet under the action of components. The main work and research results are as follows: 1, from the 5.12 Wenchuan earthquake database, were selected from the epicenter of 19 km Wenchuan Wolong earthquake wave and 634km from the epicenter of Shaanxi caotan seismic wave, and using B- spline wavelet and its 8 decomposition, wavelet components get 9 tight the adjacent non overlapping, as the input seismic wave using the analysis of base isolation system and isolation system time history, and draw their acceleration diagram and the corresponding Fourier spectrum of.2, this paper research Research shows that whether in Wolong or in different wave bands, caotan wave under the action of different frequency bands, whether or not the isolation structure isolation structure, and contains the basic frequency of the structure and the original wave frequency band of excellent structural displacement response, followed by the frequency band structure contains the basic rate of displacement response of the structure are also great. Contains the original wave frequency band of excellent structural displacement response than the first two bands under the action of the reaction, but were higher than the displacement response of the structure under the action of other bands. The equivalent static structure such as.3, high-frequency component of structure displacement contribution is very small, can ignore the high-frequency components of the displacement. With low frequency components on the displacement, displacement of the isolation structure floor almost entirely by the structure of the first mode contribution, the total displacement of the top isolation structure mostly base displacement contributions, Isolated structure layer deformation, compared with non isolated structure is greatly reduced. In the long period wave displacement under the action of various marsh isolation structure is far greater than the floor during the short period of Wolong wave isolation structure displacement, long periodic wave of isolated structure is more detrimental to.4 in Wolong wave and wavelet components under the action of equivalent the static equivalent static isolation structure is far less than the floor not all floors of the isolation structure, but in the role of caotan wave, the equivalent static equivalent static structure of various isolation and non isolation structure of each floor floor is not large, indicating isolation structure under wave effect caotan isolation effect is not so obvious. The equivalent static long period caotan wave frequency band under the action of non isolated structure of each floor is significantly less than the equivalent static short cycle of Wolong wave frequency band under the action of non isolated structure. In each floor The effects of high frequency components, the equivalent static isolated structure is much less than the equivalent static isolation structure, the isolation layer can be considered equivalent to a weak foundation, to a low pass filter, filter out some greatly seismic waves of high frequency component.5, whether in the long period caotan wave or in short period Wolong wave, the equivalent static low floor vibration mode of the structure of each play a leading role. In the first isolation structure, the proportion of each floor of the equivalent static for second modes of the largest band below 3.13Hz, the first mode of the proportion of more than second modes of the proportion of more than 3.13Hz due to the high frequency band, excitation mode, leading to the first mode of the proportion of reduced.6 in caotan wave, Wolong wave and the corresponding different frequency bands under basal shear VA1 shear VA0 and upper structure of isolation layer. Roughly equal, the shear force of the building A isolation layer is slightly larger than the base shear of the upper structure, but it will be abnormal in some frequency bands. In the 6.25~12.5Hz frequency band, the VA0 less than VA1,3.13~6.25Hz frequency band also appears.

【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU352.12

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