Analysis of Vertical Temperature Difference of the Low-Speed Maglev Steel Girder Based on Measured Data

Track irregularity is strictly controlled in low-speed maglev system. Vertical deflection due to vertical temperature difference is one of the important factors in track irregularity, which should be considered in structural design. In the field of low-speed maglev, few researches have been developed directly about the measurement of temperature and corresponding effect. In this paper, the surface temperature and deflection of a steel box girder in the low-speed maglev experimental line in Shanghai have been measured for several months. Measured surface temperature data are decomposed into temperature trend and fluctuating part with wavelet based MRA and the former is highly relevant with local climatic. In the analysis of probability distribution characteristics of the vertical temperature difference, three weighted probability models are compared, and the weighted sum model of one Weibull distribution and one normal distribution is appropriate, based on which the standard values of the temperature difference with 50-year return period are derived. To determine the correlation between the temperature difference and deflection, scatter plots of equivalent linear temperature difference obtained by deflection and measured temperature difference were fitted, and the results shows an approximate linear relationship.