Experimental and numerical investigation on the lateral force resistance of modular steel sub-frames with laminated double beam

Modular construction was widely applied since higher integrity, faster speed and less emission. Especially for COVID-19, several modular steel hospitals were urgently built for treatment and successfully contributed to epidemic control. It has been known that laminated double beam has the capability of significantly strengthening the cooperation between adjacent floor and ceiling beams in modular steel buildings. However, the effect of the superposition of laminated double beam on the lateral force resistance of modular steel structure has not been fully understood. In present study, a series of full-scale lateral experimental tests and finite element analysis were conducted to comprehensively investigate the lateral response of modular steel sub-frames with laminated double beam. Moreover, a simple validated analytical procedure was developed to support the design and assessment of modular steel buildings in engineering practice. The results show that the application of corner plug-in junction could significantly strengthen the connection of critical components of a modular steel sub-frame. The superimposed bending action of the laminated beam was demonstrated by that the strain neutral axes of the layered beams are relatively close to the interface of the beams resulting from interfacial bolt connections. It shows that the superimposition of adjacent double beams could obviously reinforce the structural integrity and lateral force resistance of a modular steel sub-frame. Furthermore, the developed analytical procedure provides an accurate and efficient method for estimating the initial lateral stiffness of modular steel sub-frames.