Seismic performance of bolted L‐shaped column‐base joints: Experimental study, numerical modeling, and design approach

Abstract L‐shaped columns have emerged as a practical load‐bearing structural scheme in industrial construction, as they effectively enhance space utilization within building layouts. Conventional cast‐in‐place L‐shaped column‐base joints often suffer from low construction efficiency, limited quality controllability, and high labor costs. To address these issues, this study proposes a prefabricated L‐shaped column‐base joint mechanically assembled using high‐strength bolts with localized post‐cast grouting in the connection region, aiming to achieve reliable seismic performance and improved construction standardization. Three specimens, including two prefabricated bolted joints and one cast‐in‐place joint, were designed and cyclically tested to investigate the load‐bearing mechanism and failure characteristics of prefabricated bolted joints. The results indicated that the strength, stiffness, and ductility of the L‐shaped bolted joints are comparable to those of the cast‐in‐place joint. In the cracking stage, the drift ratio of the bolted joints reached 1/400, and in the failure stage, it reached 1/50. Finite‐element modeling and validation of the proposed L‐shaped column‐base joint were performed using ABAQUS. Subsequently, a parametric study was conducted to investigate the effects of axial load ratio and grout strength grade on the joint's mechanical response. Finally, based on the analysis results, an application‐oriented parameter‐selection table was developed, which provides direct design guidance for engineering applications of the joint.