Bidirectional Shear Performance of Corroded Stud Connectors in Steel–Concrete Composite Monorail Track Beams

Under the combined action of bidirectional (longitudinal and transverse) shear loads and corrosive environments, the shear performance of stud connectors in steel–concrete composite track beams of straddle-type monorail transit systems is susceptible to degradation, thereby posing a potential risk to the structural safety of the track girders. This study employs push-out tests and numerical simulations to investigate the influence of bidirectional shear loads and stud corrosion on the shear performance of stud connectors. The results showed that both transverse shear loads and stud corrosion lead to a reduction in the shear capacity of stud connectors, with their coupling effect amplifying the degradation. Transverse shear loads induce an accelerated decay trend in the load-bearing capacity of stud connectors, while an increase in corrosion depth results in a linear degradation of the load-bearing capacity. The corrosion depth at the stud root exerts a more pronounced influence on shear performance compared to the corrosion height. Furthermore, the dominant failure mode of stud connectors manifests as root fracture, while transverse shear loads induce alterations in the concrete damage zone. Based on the verified FE model, a shear capacity reduction factor accounting for the coupling effects of bidirectional shear and stud corrosion was established to improve the Oehlers model. This research provides critical theoretical support for the safe design and durability assessment of monorail track girders.