Upgrading the Structural Performance of Precast Slab–column Connections under Eccentric Loading

The structural performance of precast reinforced concrete (RC) slab-to-column connections remain a critical challenge due to the inherent discontinuity at the interface, which often leads to premature cracking, limited load transfer capacity, and brittle failure modes, particularly when the column is a concrete core encased within a steel box. This study investigates the structural performance of reinforced concrete slab-to-precast column connections, where the columns consist of concrete cores encased in steel boxes. A comprehensive numerical program was developed using ABAQUS to evaluate different mechanical connection strategies, including welded steel bars, anchorage bolts with varying embedment lengths, reinforcement spacing optimization, steel meshes, and embedded steel sections. The models were validated against reference configurations and then used to assess cracking load, ultimate load capacity, elastic stiffness, and load–deflection behaviour. The results demonstrate that all strengthening techniques significantly enhance connection performance compared to the unstrengthened case. Cracking loads increased by up to about 550