Theoretical Prediction and Evaluation of Rail Deformation for CRTS II Ballastless Track Under Creep Camber of Girders

The time‐dependent deformation due to creep in simply supported girders represents a key controlling factor for the long‐term service performance of ballastless tracks. Accordingly, establishing the correlation between girder deformation and long‐term track irregularity provides the theoretical basis for the safety assessment of track structures. Taking a CRTS II slab ballastless track–simply supported girder system as the investigation case, an analytical mapping model between the creep camber of girder (CCOG) and rail deformation was established by equating the ballastless track to a composite beam and incorporating numerical predictions of the CCOG. Deformation compatibility and void length between the girder and the ballastless track were investigated, and rail smoothness was evaluated using the local peak value (LPV) of rail deformation and the vertical track quality index (VTQI). Results revealed that the CCOG peaks at 3.423 mm at approximately 14 years of service (which remains within the specified thresholds), inducing a maximum vertical deformation difference of 0.562 mm between the girder and the base slab. The maximum deviation between the analytical and numerical results for the LPV of rail deformation is as low as 0.77%, indicating that the proposed theory for rail deformation provides satisfactory predictions. Under the effect of the CCOG, the LPV of rail deformation is within the specified thresholds, whereas the VTQI exceeds the threshold at about 4.7 years. Considering the randomness of the CCOG, the LPV of rail deformation presents a certain probability of exceeding the threshold but mainly falls within Level I management requirements, while the time when the VTQI exceeds the threshold may be significantly advanced. Therefore, the randomness of CCOG should be taken into account in the evaluation of long‐term rail deformation.