Thermal effect analysis of a steel truss cable-stayed bridge with two-layer decks under sunlight

Due to the sheltering effect of the upper structures and the significant influence of temperature changes in the cables, the steel truss cable-stayed bridge with two-layer decks exhibits complex spatial thermal effects under solar radiation and environmental temperature. In order to study the temperature distribution characteristics and thermal deformation during the construction stage, the thermal effect of a steel truss cable-stayed bridge with two-layer decks under construction is analyzed through numerical simulation. Firstly, a temperature field analysis algorithm, which considers geo-meteorological factors and the sheltering relationship between members, was used to simulate the structure's transient temperature field and thermal deformation. Then, the temperature distribution characteristics and thermal deformation under the influence of seasons were discussed. The results indicated that the web members and the lower deck showed a significant temperature difference when shaded by the upper structure, with a maximum temperature difference of 7.6°C; The transverse temperature difference of the lower chord was the main factor controlling the transverse deformation of the steel truss girder; During a day in summer, the maximum vertical, longitudinal, and transverse deformations of the main members at the closure during the maximum single cantilever stage were 7.2 cm, 6.4 cm, and 5.9 cm, respectively.