中文摘要：

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。

英文摘要：

GPS has been widely used in healthy monitoring of bridge because it can collect useful data of all-weather, high resolution and precision deformation. The GPS time series signals can be transformed into frequency domain by Fourier transform method. With the help of spectrum analysis, periodical signals should be distilled, and thus, bridge healthy status can be evaluated. According to GPS measurements of Donghai bridge from June 19-July 1, 2006, this paper finds that the thermal expansion above 3cm is the main periodical deformation just within 1 day. Besides, the deformation caused by ocean load tide is about 7 mm in half day. And there is no significant non-periodical trend. In view of this, it could prove that the bridge is in good status.