Temperature field characteristics of concrete box girders in rigid-frame bridges based on fine simulation and monitoring

The non-uniform temperature distribution in long-span double-box single-cell concrete box girder bridges can lead to reduction in structural bearing capacity and temperature-induced diseases. In this paper, a fine simulation method for two-dimensional non-uniform temperature field of double-box single-cell concrete box girders is proposed. The temperature time history and temperature gradients are validated based on long-term measurement data from temperature monitoring in long-span single-pier rigid-frame bridge. The proposed simulation method is used to recover missing data for temperature measurement points. Vertical and transverse temperature distribution characteristics of the box girder are investigated by combining measured values, simulated values and statistical analysis method. The average annual temperature of box girder is 20.10°C, with daily temperature variations ranging from 0.15°C to 2.96°C at all measurement points. The standard values and models of the most disadvantageous vertical in dayside web and transverse temperature difference are obtained. The results indicate that the temperature distribution of double-box single-cell concrete box girders has obvious non-uniformity. Some temperature difference models differ from the gradient patterns specified in the code substantially. The research results of this study can supply references for temperature field simulation, temperature effects calculation, and codes design for long-span double-box single-cell concrete box girder bridges.