Experimental and Finite Element Analysis of the Built‐Up Hot‐Rolled Channel Steel Beams

Built‐up hot‐rolled channel steel beams are crucial for modern construction due to their excellent structural efficiency, yet existing studies mainly focus on cold‐formed thin‐walled built‐up beams, leaving gaps in understanding the bending performance of hot‐rolled counterparts. This study investigates the flexural performance of double‐limb built‐up hot‐rolled channel steel beams through four‐point bending tests (eight specimens) and Abaqus finite element (FE) analysis, considering parameters like bolt spacing, bolt preload, steel yield strength, and geometric ratios. Technically, it quantifies the relationship between key parameters and flexural performance (e.g., bolt spacing from L/3 to L/4 reduces ultimate capacity by up to 20.52%, with an optimal range of L/6 to L/4) and develops a dumbbell‐shaped bolt FE model (calculation error < 5%) to balance computational accuracy and efficiency. Theoretically, it reveals two novel findings: The weaker component dominates the overall load‐bearing capacity when there is a significant difference in steel yield strength between the two limbs, and the adverse effect of increasing span‐to‐height ratio on structural capacity is more pronounced at higher height‐to‐width ratios—both enriching the stability analysis theory of built‐up steel beams. These results provide practical design references and promote the application of such beams in seismic and high‐load environments.