Analysis of Sunshine Temperature Field of Steel Box Girder Based on Monitoring Data

Table 1

Thermophysical parameters of the materials.

Parameters	Asphalt concrete	Concrete	Q345C steel	Painting^a
Density (kg/m^3)	2100	2300	7850	—
Specific heat (J/kg·°C)	886	1010	480	—
Conductivity (W/m·°C)	1.17	0.98	48	—
Absorptivity	0.93	—	—	0.28
Emissivity	0.93	—	—	0.87
Heat coefficient	—	7	5	—

^aThe absorptivity of radiation on the surface of steel box girder is related to the color of the coating, and the bridge surface is painted in white.