Vertical temperature gradients of concrete box girder caused by solar radiation in Sichuan-Tibet railway
Tao Shi, Xingwang Sheng, Weiqi Zheng, Ping Lou
Abstract
Spatial and temporal temperature variations are critical for concrete box girders, and non-uniform temperature distributions induced by solar radiation depend on the structural shapes and shadows cast on them. There have been many studies of temperature distributions and temperature gradients of concrete box girders, but few have considered a high altitude plateau climatic environment. In this study, the nonlinear temperature distributions of concrete box girders in the Sichuan-Tibet railway caused by solar radiation were investigated based on experimental analysis, real-time shadow-selection algorithm, and finite element method. Furthermore, a vertical temperature gradient model of the concrete box girders was obtained. The vertical temperature gradient values first rise, then decrease, and finally rise again from Chengdu to Lhasa, with samples forming a normal distribution. The recommended vertical temperature gradient value was 25 °C with a confidence interval of 95%. This provides a reference for the design and maintenance of concrete box girders on the Sichuan-Tibet railway.