The monitoring of temperature differences between steel truss members in long-span truss bridges compared with bridge design codes

摘要

The temperature differences in bridge structures have been one primary concern for bridge engineers and researchers. In the traditional view, the temperature differences between steel truss members are treated as uniform because of the good heat transfer characteristic of steel material and the shading effect of deck coverage. However, for some steel truss bridges, some truss members are directly exposed to solar radiation, while some other truss members are totally shaded by steel decks, which may cause obvious temperature differences between them, so it is reasonable to doubt the correctness of uniform temperature existing between steel truss members. In this research, the temperature differences between steel truss members in two long-span truss bridges are analyzed using long-term temperature field data, and after analysis, the temperature differences which contain obvious positive or negative values are made clear. Furthermore, the evaluation method of temperature differences in bridge service life for thermal action design is put forward together with the determination method of probability density function, and the evaluated temperature differences are further obtained after probability statistics analysis. Finally, the evaluated temperature differences are classified by sun radiation and steel deck coverage, and then compared with the specified values in the three specifications. The research results can provide important reference for current specifications and structural design, especially for steel truss bridges.