Abstract:In order to explore the temperature field distribution characteristics and thermal effect of corrugated steel web (CSW) box girder in dry cold region, and to make up for the lack of the definition of temperature gradient mode of CSW box girder in the current standard, a new-pattern composite box girder bridge with CSWs in dry cold region of Northwest China was taken as the research object. Based on the field thermal observation data, the temperature distribution law of the new composite structure under the action of sunshine was analyzed, and the 2D temperature gradient model was proposed by least square fitting. By establishing the refined FEM of the new-pattern composite box girder with CSWs, the temperature response of the bridge was calculated based on the measured temperature gradient function, and the influence of profiled steel plate on the thermal stress of the composite box girder was analyzed. The results showed that the 2D temperature gradient of CSW box girder of vertical piecewise polynomial and transverse exponential function based on field measured data was in good agreement with the calculated value of measured temperature field, which could provide necessary reference for the calculation of similar engineering temperature load in this climate area. Under the action of solar temperature, there was a significant temperature gradient at the interface between the top plate and the web plate of the new-pattern CSW composite box girder. Transverse tensile stresses up to 2.42, 1.83 and 1.26 MPa appeared at the upper edge of the flange plate, the top plate web interface and the central axis of each box chamber, respectively, which might induce cracks in the deck and attention should be paid in the design. Under the measured temperature gradient, the transverse tensile stress of the upper edge of the central axis of each box chamber roof could be reduced by more than 0.5 MPa by the closed profiled steel sheet, which was beneficial to the crack resistance of the bridge deck. While the open profiled steel plate could increase the transverse tensile stress of the upper edge of the flange plate of each box chamber by 15%～18%, which was unfavorable to the crack resistance of the bridge deck.