Experimental and theoretical analysis of thermal-structural coupling of CRTS Ⅲ slab track on long-span bridges under continuous high-temperature

Under continuous high-temperature (HT) conditions, CRTS Ⅲ slab track on long-span bridges is prone to internal heat accumulation and thermal stress concentration. This study proposes a thermal-structural coupling analysis method for slab track on long-span bridges under continuous HT. A full-scale field experiment of the temperature distribution and thermal deformation of slab track is performed to validate the refined finite element (FE) model and obtain the thermal behavior of slab track. The extreme temperature of each layer in the slab track exhibits noticeable hysteresis. The maximum positive vertical temperature gradients (VTGs) in the middle and bottom of track slab are 104.25 °C/m and 74.25 °C/m, respectively. The upper layer of track slab exhibits greater strain than the lower layer during the daytime, while the opposite trend appears at night. Based on the refined FE model of slab track on long-span bridges under continuous HT, the slab track on long-span bridges mainly exhibits the accumulation of longitudinal stress and the deterioration of track geometry in the first four days. Compared to the second day, the longitudinal stresses of track slab, self-compacting concrete (SCC), and base slab increase by 10.56%, 129.63%, and 83.1%, respectively, on the sixth day. The cross level of rail exhibits the most pronounced variation, increasing by 34.53% on the sixth day compared to the second day. The proposed thermal-structural coupling analysis method provides valuable guidance for designing and maintaining the slab track on long-span bridges under continuous HT.