Numerical Analysis and Design of a Telescopic Joint for Rapid Assembly of Steel Frames

Steel modular construction is increasingly adopted due to its high level of prefabrication and rapid on-site assembly; however, its widespread application remains constrained by the tolerance sensitivity of structural connections. Conventional bolted joints require precise geometric alignment, often resulting in time-consuming assembly procedures and increased construction complexity. This study introduces a novel telescopic beam-to-column joint for rectangular hollow section (RHS) steel frames, explicitly conceived to accommodate geometric tolerances through a geometry-driven assembly mechanism. The proposed system enables vertical insertion of beams into pre-welded column supports, where gravity-assisted positioning ensures initial alignment, while bolted fastening provides structural continuity and load transfer. A nonlinear finite element framework, calibrated against experimental data available in the literature, is employed to investigate four joint configurations characterized by increasing levels of geometric confinement and stiffness. The findings highlight that connection systems explicitly designed to accommodate geometric tolerances can simultaneously improve constructability and structural performance, providing a viable design strategy for modular steel buildings and industrialized construction.