Probabilistic statistical evaluation of the design values of temperature differences of steel truss girder bridges through finite element simulation and monitoring data analysis

At present, steel truss girder bridges have been widely used because of its light weight and high strength. Existing studies have shown that the temperature field of steel truss bridges will produce adverse effects such as concrete slab cracking and bridge support diseases, but current bridge design specifications do not clearly stipulate the temperature difference of steel trusses, and only uniform temperate action is considered for steel truss girder bridges. Therefore, this research carried out a study on temperature differences of steel truss girder bridges. In detail, the monitoring temperature differences of a steel truss bridge are analyzed by virtual of bridge health monitoring system; then, finite element simulation is carried out to reveal the reason of existing big temperature differences; finally, the design values of temperature differences are calculated to provide reference for bridge design through probabilistic statistical analysis. The results show that there are big temperature differences between some steel truss members, and the maximum value reaches 14.7 °C; the shade length of deck flange under solar radiation is an important influence factor of causing big temperature difference; generalized extreme value (GEV) distribution is the best distribution to fit cumulative probabilities, the maximum design value of temperature differences is 22.11 °C, and the minimum design value of temperature differences is −17.56 °C, which may lead to significant temperature effects; the design temperatures of M₁, M₂, M₃ and M₅ are 0 °C, and the design temperatures of M₄ and M₆ are 19.75 °C and 22.11 °C, respectively. The research results will provide important reference for temperature action design of steel truss bridges.