Temperature Field Observation And Temperature Effect Analysis Of Prestressed Concrete Box-girder Bridge

The temperature effect on concrete box-girder bridges directly affects the safety and durability of bridges. Large deformation and stress will be produced in the bridge under the thermal load. Especially during the cantilever construction of bridges, the deformation of bridges due to temperature has impacted the initialize heights of girders in construction state, and further affects the profile of finished bridges. This paper focus on the temperature field and temperature effect of concrete box-girder bridge based on the long term observation of an existing bridge, and the results provide reference for the bridge criterion on temperature field of concrete box-girder.The variety of temperature field of concrete box-girder on solar radiation, weather and season is analyzed based on one year observation of a long-span continuous rigid frame concrete box girder bridge. The temperature effect of this bridge is measured simultaneously through recording the temperature stress at midspan. Then the relationship between temperature field and temperature stress is obtained through measuring data. In addition, the deflection of box-girders in the cantilever construction stage is measured at the same time to analyze the relationship between temperature gradient and deflection on box-girder.A 2D finite element model is established according to heat transfer theory. The first boundary condition is applied in calculating the temperature field of box-girder. By comparing the numerical results to the measured ones, it is found that the numerical results are close to measured ones in the first boundary condition.In addition, this paper compared and analyzed the temperature effect between measured results and numerical results from beam element model. In the end, the existent problem caused by adopting beam element method to simulate the temperature effect was discussed.