Seismic Performance of Prefabricated Steel–Timber Hybrid Joint: Experimental and Numerical Study

Existing steel–timber structures may exhibit limited composite action between the two materials. To address this issue, this study proposes a novel sleeve-connected prefabricated steel–timber (SCPST) beam–column joint that utilizes steel sleeves and high-strength bolts for assembly. To assess its seismic performance, five full-scale interior joint specimens with different beam-sleeve thicknesses and lengths were tested under low-cycle reversed loading. The experimental results revealed that deformation and damage were concentrated at the beam ends, whereas the timber columns remained essentially elastic, satisfying the strong-column–weak-beam seismic design objectives. Within the tested specimen matrix, the peak load of the specimen with an 8 mm beam-sleeve thickness was 43.75% higher than that of the 4 mm specimen, while that of the specimen with a 400 mm sleeve length was 17.46% higher than that of the 300 mm specimen. Frictional slip at the timber–steel interfaces and yielding of the stiffeners were identified as the primary energy-dissipation mechanisms. Simplified analytical expressions based on Eurocode 3 and Chinese timber design provisions were developed to evaluate three potential beam-end failure modes, and the calculated resistances differed from the experimental results by less than 10%. A simplified finite element model was also established in ABAQUS. The simulated failure patterns and peak loads were in reasonable agreement with the experimental observations, with average peak-load errors of 2–6%. These results indicate that the analytical resistance estimates and simplified numerical model can provide a preliminary basis for evaluating the resistance and global response of SCPST joints within the investigated parameter range.