Time-History Analysis of Temperature Field of Medium-Low Maglev Guideway Girder

To master the laws of time-varying temperature fields of maglev girders generated by long-term environmental loading, thermal sensors were installed on a concrete guideway girder in the Changsha Maglev Express. By performing up to 1.5 a of site monitoring, the time-history curve of points was obtained. A method based on the time-series addition model is presented. With this method, the original temperature is decomposed into uniform temperature and fluctuating temperature, and the time-history curves of both temperatures are analysed using the Fourier curve fitting method. Then, the time-varying temperature field of the guideway girder is determined. The results show that uniform temperature is relevant to the climate, and each point is basically the same, reflecting the trend of the original temperature. The overall time-history curve of the girder can be expressed as a cosine function with a median value of 20.41 ℃, amplitude of 12.61 ℃, initial phase of 20 d, and cycle of 365 d. The fluctuating temperature is mainly because of solar radiation, and the curves fluctuate near the zero line. Two sine functions can be used to fit the rising and falling time-history curves.