基于小波变换的长周期桥梁选波方法研究

Study on Wave Selection Method of Long-period Bridges Based on Wavelet Transform

时程分析输入地震波的选取对长周期大跨度桥梁影响显著。本文基于规范目标谱,以MATLAB为依托,通过选取最优小波基并利用小波系数迭代法实现频域调整,使地震波反应谱不断逼近给定目标谱,最后结合相对误差和长周期拟合参数两个指标进行综合评价,选取适用于长周期大跨度桥梁的时程分析地震波,提出长周期桥梁全过程批量选波方法。将该方法应用于奉节长江大桥,与基于时域调整方法的Seismo Match选波软件对比选波效果,并将选波结果应用于背景桥梁的时程分析。结果表明,利用本文选波方法所得结构关键截面响应与软件选波所得响应在横桥向和竖桥向存在一定差异。本文方法可为长周期大跨度桥梁时程分析选波提供参考。

In the time history analysis,the selection of seismic waves has a significant impact on long-period and long-span bridges.Based on the standard target spectrum and MATLAB program,in this paper we select the optimal wavelet base and use the wavelet coefficient iteration method to achieve frequency domain adjustment,so that the seismic wave response spectrum can continuously approach the given target spectrum.Moreover,by using two parameters including relative error and long-period fitting parameter to make a comprehensive evaluation,we are able to select seismic waves applicable to long-period and long-span bridge in the time-history analysis,and to propose a whole-process batch wave selection method for long-period bridges.The method is applied to Fengjie Yangtze River Bridge,and the effects of wave selection are compared with Seismo Match wave selection software based on time domain adjustment method.The results of wave selections are applied to the time-history analysis of the background bridges.The results indicate that there exists the certain difference between the key section response obtained by the wave selection method in this thesis and the response obtained by the software wave selection in the transverse and vertical bridge directions.The method in this paper can provide references for wave selections in time-history analysis of long-period and long-span bridges.