Observation and research on temperature distribution of concrete box girder in diurnal change of temperature

This paper investigates temperature distribution in concrete box girder which is prefabricated in the precast yard, under the influence of diurnal change of temperature. One concrete box girder in the precast yard of Liutiaohe Bridge is experimental subject. Observation data of four days were collected by embedded sensors and non-contact infrared thermo detector. And regression analysis is used to study observation data by using the nonlinear least squares method. Experimental results show that difference of transverse temperature gradient is large in outboard web, bottom slab. The difference of vertical temperature gradient is also big at top plate. Furthermore, there mainly shows vertical negative differential temperature in concrete box girder. And a regression equation is proposed.