Pull-Out Performance Analysis of PBL Joint of Beam-Truss Composite Structure

This technical note presents a practical numerical evaluation of the pull-out behavior of an embedded multi-plate PBL joint in a steel–concrete composite box girder, using the Hanjiang Bridge on the Xi’an–Shiyan High-Speed Railway as an engineering case. A three-dimensional nonlinear finite element model was established to investigate the pull-out capacity, stress distribution, and load-transfer characteristics of the joint, with particular emphasis on the effects of steel-plate spacing and transverse reinforcement arrangement. The results indicate that steel-plate spacing influences the load sharing among the perforated steel plates and leads to a nonuniform stress distribution in the transverse reinforcement. The pull-out capacity predicted by the finite element model differs from that obtained using existing empirical formulas developed primarily for single-plate PBL connectors, suggesting that the interaction among multiple steel plates is not explicitly represented in these formulations. However, because the finite element model has not been validated against direct pull-out test data for the investigated joint, the findings should be regarded as case-specific numerical observations rather than generally applicable conclusions. This study provides a practical basis for evaluating the pull-out behavior of similar embedded multi-plate PBL joints and identifies key parameters requiring further experimental verification.