Calculation of standard values of temperature differences in a large-span steel-concrete composite girder bridge through probabilistic statistics and cycle-life simulation analysis

Abstract

Using the monitoring temperature data from a large-span steel-concrete composite girder bridge, the spatial distribution laws of the transversal and vertical temperature differences in the steel-concrete composite girder are analyzed; then, the probabilistic statistical characteristics of the daily extreme values of temperature differences are analyzed using probability statistical method, and then cycle-life simulation is carried out to obtain the yearly maximum or minimum values in the whole bridge service life; furthermore, the standard values of positive and negative temperature differences are calculated, and finally the correlation between the standard values and the monitoring extreme values are explored using correlation analysis method. The results show that: (1) there are significant transversal and vertical temperature differences in the steel-concrete composite girder, and the maximum positive temperature difference in the transversal direction of this girder reaches 7.40°C, and the minimum negative temperature difference in the vertical direction reaches −6.80°C; (2) the generalized extreme value distribution (GEVD) has a smaller fitting error 0.0016 compared to the extreme value distribution (EVD) and the normal distribution (ND), so GEVD is selected as the optimal probability density function; (3) the maximum and minimum values of standard values for transversal temperature differences are 10.74°C and −6.38°C, respectively; the maximum and minimum values of standard values for vertical temperature differences are 4.81°C and −7.77°C, respectively; (4) there is a good linear correlation between the measured values and the standard values, with a linear correlation coefficient of 0.9044; (5) there is a big difference between current bridge codes and the calculation results by comparison, hence the actual standard values of temperature difference for steel-concrete composite girder bridges is relatively complex, and the calculation results can provide an important reference for the current bridge codes.