基于CNN的考虑地震波时频特征影响选波方法研究

RESEARCH ON GROUND MOTION SELECTION METHOD CONSIDERING THE IMPACT OF TIME AND FREQUENCY CHARACTERISTICS OF GROUND MOTIONS BASED ON CNN

  • 摘要: 地震波的时域特征对高层建筑地震反应有显著影响,而现有地震波选取方法并未有效考虑地震波时域特征的影响,导致高层建筑弹塑性时程分析结果不合理。该文在现有选波方法的基础上,提出了一种基于卷积神经网络(CNN)的选波方法以有效考虑地震波时频特征对结构地震反应的影响。该选波方法采用弹性时域反应图表征地震波时域特征对建筑结构地震反应的影响,结合迁移学习方法搭建并训练CNN模型,建立建筑结构地震反应与地震波弹性时域反应图之间的映射关系。利用训练好的CNN模型判断备选地震波时域特征对结构地震反应的影响,并完成选波。采用该文提出的基于CNN选波方法和现有选波方法对6个周期不同的高层结构进行选波测试及验证。结构弹塑性时程分析结果显示,基于CNN选波方法可以在少量地震动记录的输入下,实现对大量地震动输入下结构响应的稳定估计,显著提高弹塑性时程分析结果合理性。

     

    Abstract: The seismic response of tall buildings is influenced by the time characteristics of ground motions. However, existing ground motion selection methods inadequately account for the impact of time characteristics, leading to noticeable irrationality in the results of nonlinear response time-history analysis of tall buildings. Based on the existing two-step ground motion selection procedure, a ground motion selection method considering the impact of time and frequency characteristics of ground motions based on the convolutional neural network (CNN) was proposed. The proposed method employed the elastic response diagram in the time-domain (RDTD) to represent the impact of the time characteristics of ground motions and consider the impact of time characteristics. The CNN model was selected and trained with transfer learning technique to establish the mapping relations between the characteristics of the RDTD and the seismic response of tall buildings. The trained CNN model was then used to evaluate the impact of the time characteristics of candidate ground motions, and select ground motions for the nonlinear response time-history analysis of building structures. The proposed method was compared with existing selection techniques on six structures with varying vibration periods. The results demonstrated that the CNN-based approach enabled accurate seismic response calculations with a fewer number of ground motions, achieving comparable outcomes to those obtained with a larger set of ground motions. This substantial improvement in the rationality of nonlinear response time-history analysis had promising implications for tall building seismic assessment and design.

     

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