基于汶川地震记录的远场长周期地震动设计反应谱研究

发布时间：2018-08-29 11:07

【摘要】：合理的长周期地震动输入对长周期结构的抗震设计至关重要。日本在长周期地震动输入问题的研究上取得了丰硕的成果,并在工程设计中得到了良好实践,我国地震环境和抗震设防思想不同于日本,不可照搬日本研究成果。当前国内对长周期地震动输入问题的研究远不能满足工程实践需求,对规范设计谱长周期段的设定和调整争议不断,显然,对不同的地震动类型,设计反应谱长周期段的设定应有所不同。基于上述原因,文章以汶川地震记录为基础,分别研究了常规地震动和远场长周期地震动的设计反应谱,研究的主要工作内容如下:(1)对收集到的汶川记录进行基线校正和滤波处理,并计算了每条地震记录的加速度、速度反应谱以及相关的地震动参数;(2)对所有地震记录的多个频谱参数进行了计算和统计分析,结合震中距和峰值速度,筛选出本文的远场长周期地震动;(3)为完善长周期结构的地震输入,先拟合形成与远场长周期地震动设计谱相对比的常规地震动设计反应谱,并利用遗传算法进行设计参数的标定计算;(4)对所选远场长周期地震动进行了速度设计谱拟合分析和设计参数的标定计算,借助拟谱关系,获得对应的长周期地震动加速度设计谱。通过以上研究,主要得到以下结论和成果:(1)加速度反应谱平均周期Tavg适合评估地震动的频谱特性,本文提出选用Tavg、震中距和速度峰值作为远场长周期地震动的界定指标;(2)拟合得到了新的常规地震动设计反应谱,并给出了不同设计条件下拟合设计谱参数取值建议;(3)利用遗传算法进行反应谱拟合能获得良好的拟合效果;(4)拟合得到了能与我国抗震设计方法接轨的长周期地震动速度设计谱,并给出了不同设计条件下拟合设计谱参数取值建议,通过拟谱关系,得到了对应的加速度设计谱。与规范相比,文章得到的远场长周期地震动拟合设计谱能更好地反映长周期地震动的反应谱特征。
[Abstract]:Reasonable input of long period ground motion is very important for seismic design of long period structure. In Japan, great achievements have been made in the study of long-period earthquake input, and good practice has been obtained in the engineering design. The earthquake environment and anti-seismic fortification in China are different from Japan, so it is not possible to copy the Japanese research results. At present, the domestic research on the input problem of long-period ground motion is far from meeting the requirement of engineering practice. There are many disputes about the setting and adjustment of the long-period section of the code design spectrum. Obviously, for different types of ground motion, The design of the long period response spectrum should be different. Based on the Wenchuan earthquake records, the design response spectra of conventional and far-field long-period ground motions are studied. The main work of the study is as follows: (1) the baseline correction and filtering of the collected Wenchuan records are carried out, and the acceleration of each seismic record is calculated. Velocity response spectrum and related seismic parameters. (2) calculation and statistical analysis of multiple spectral parameters of all seismic records, combined with epicentral distance and peak velocity, (3) in order to perfect the seismic input of long-period structure, the conventional seismic design response spectrum, which is compared with the design spectrum of far-field long-period ground motion, is formed. Genetic algorithm is used to calibrate the design parameters. (4) the velocity design spectrum fitting analysis and the calibration calculation of the design parameters are carried out for the selected far-field long-period ground motion, and the pseudospectral relationship is used. The corresponding design spectrum of long-period ground motion acceleration is obtained. Through the above research, the following conclusions and results are obtained: (1) the average period Tavg of acceleration response spectrum is suitable for evaluating the spectral characteristics of ground motion. In this paper, Tavg, epicentral distance and peak velocity are selected as the defining indexes of long-period far-field ground motions. (2) A new conventional seismic response spectrum is obtained by fitting. At the same time, some suggestions of fitting design spectrum parameters under different design conditions are given; (3) response spectrum fitting with genetic algorithm can get good fitting effect; (4) long period seismic velocity design spectrum, which is in line with the seismic design method of our country, is obtained by fitting. The corresponding acceleration design spectrum is obtained by pseudospectral relation. Compared with the code, the design spectrum obtained in this paper can better reflect the characteristics of the response spectrum of the long-period ground motion.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU352.11

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