Temperature gradient of flat steel box girder in suspension bridge

Based on case engineering Runyang Bridge, the temperature gradient of flat steel box girder in suspension bridge was continuously observed. According to the analysis of measured datum, the temperature gradient on flat steel box girder was proposed. With three temperature gradient models (JTG D60-2004 specification, BS5400 specification and the temperature gradient which was proposed in this paper), the control sections stress was calculated by finite element program ANSYS. The calculated result indicates that the temperature gradient that was put forward in JTG D60-2004 specification and BS5400 specification for calculating stress of flat steel box girder was not suitable to apply to flat steel box girder and inclines to unsafe. The temperature gradient on flat steel box girder which was proposed in this paper was reasonable.