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GPS因其能够全天候、高精度、高分辨率地采集桥梁形变数据,在桥梁健康监测中得到了广泛的应用。桥梁形变GPS观测数据是由多种低频和高频周期信号叠加的时间序列,需要通过傅立叶变换将其转换到频域空间,通过频谱分析可提取各种周期项信息,分析这些周期变形的激发机制,进而鉴别桥梁的健康状况。本文根据东海大桥2006年6月19日至2006年7月1日共13天的GPS监测数据,通过频谱分析发现该大桥的周期形变主要是温度变化引起的热胀冷缩,平均形变量为3cm以上,周期为一天;其次初步判断潮汐引起的周期为半天的平均变形量约为7mm,没有发现非周期的趋势性的形变,反映出该桥梁状态正常。
GPS is widely used in the bridge health monitoring because it can collect the deformation data of the bridge all-weather, high-precision and high-resolution. Bridge deformation GPS observation data is composed of a variety of low frequency and high frequency periodic signal superimposed time series, need to be transformed into the frequency domain space by Fourier transform, spectral analysis can extract a variety of periodic information, analysis of these periodic deformation of the excitation mechanism , And then identify the bridge’s health status. According to the GPS monitoring data of Donghai Bridge from June 19, 2006 to July 1, 2006, a total of 13 days of GPS monitoring data are obtained. Through spectral analysis, it is found that the periodic deformation of the bridge is mainly caused by thermal expansion and contraction with the average deformation of 3 cm , And the period is one day. Secondly, the average deformation caused by the tidal cycle is estimated to be about 7 mm for the first half of the day. No aperiodic trend of deformation is observed, which indicates that the bridge is in normal condition.