A novel boltless interlocking steel modular building system: Design, construction and mechanical performance

This study proposes and evaluates a steel modular building (SMB) system employing a novel boltless interlocking, which balances the requirements of rapid assembly/ disassembly with enhanced structural performance. This boltless interlocking SMB system utilizes a self-adapting and self-locking interlocking mechanism, ensuring excellent connection reliability and ultra-high strength, while significantly simplifying the construction process of the SMB. It provides an effective solution for the automated assembly and tolerance control of modular buildings, which promises to considerably accelerate the automation in construction. As the joint configuration of this system possesses highly complex geometry, it is difficult to model directly and accurately in conventional finite element environments. Therefore, this paper employs Rhino software for three-dimensional geometric modeling and imports the data seamlessly into the Abaqus platform to perform finite element analysis, thus achieving high-fidelity numerical simulations that accurately reflect the complex geometry. Using numerical simulation methods, this paper analyzes the mechanical response of a three-story SMB structure under gravity load, wind load, seismic action, and a corner column failure scenario. The results demonstrate that the boltless interlocking system substantially enhances the tensile, shear, and bending capacities of the joints, with its load capacity being approximately five times that of traditional bolted connections. Under gravity load, the maximum floor slab displacement is only 7.45 mm, indicating excellent overall stability of the structure. The structural performance of SMB under lateral loads is satisfactory, with maximum inter-story drift ratios of 0.035% and 0.062% under combined wind-gravity and seismic-gravity loads, respectively. Anti-progressive collapse analysis indicates that the SMB structure can develop an efficient alternative load path after the failure of a corner column, with an ultimate load capacity reaching 1315 kN.