Mechanical characteristics and damage evolution of anchorage system in bridge-subgrade transition section under temperature loads

Purpose: The longitudinally connected slab ballastless track (LCSBT) in the bridge-subgrade transition section is highly sensitive to temperature variations. To counterbalance the resultant longitudinal thermal forces, an end stab anchorage system is installed in the subgrade behind the abutment. This system features a serrated structure with clear mechanical behavior and an efficient locking effect. The paper addresses the issues associated with this system. Design/methodology/approach: A high-fidelity finite element (FE) model of the LCSBT that integrates the subgrade, transition and bridge sections is developed by utilizing in situ monitoring data. Through comprehensive qualitative and quantitative investigations, the mechanical characteristics of the end stab anchorage system and the evolution mechanism of structural damage under temperature loads in summer and winter are elucidated. Furthermore, key control indicators of the concealed anchorage system are proposed based on existing technical data and stress-deformation characteristics. Findings: The results indicate that the main end stab area is particularly vulnerable to high-temperature loads, with the maximum longitudinal stress and deformation occurring at the vertical wall of end stab II. Structural damage in the end stab area follows a periodic pattern that aligns with seasonal temperature fluctuations. The recommended control indicators for longitudinal stress and deformation of the end stab anchorage system are 9.84 MPa and 2.76 mm, respectively. Originality/value: These conclusions provide invaluable insights for enhancing the reliability and performance of the anchorage system in the bridge-subgrade transition section, and present practical implications for the design, evaluation and maintenance of comparable systems in engineering practice.