Research On Mechanical Behavior Of Self-locking Inter-module Connection Of Modular Steel Buildings

Modular steel building(MSB)is a modern style of building form that divides the conventional form of building into three-dimensional modular units that are prefabricated and fully-decorated in the factories,transported to the site,and assembled as a whole building blocks.As the high-end product of prefabricated building,MSBs have a wide development foreground with outstanding advantages of speedy construction,superior engineering quality,saving human power and reduced environmental impact,etc.As a typical connection of MSBs,the inter-module connection is characterized by the connection of "multi-columns and multi-beams",and its structural form and mechanical performance plays a key role in the convenience of on-site installation and structural safety,which has become the research hotspot of experts and scholars in recent years.The existing connection forms have the limitations of high welding quality requirements,high installation difficulty and low construction efficiency.And most connections still cannot meet the requirements of connection in middle modules.To address the above problems,this paper proposed a self-locking inter-module connection,which effectively solves the problem of no operation space at the middle modules.This connection has the outstanding advantages of simple construction and fast construction efficiency.Due to the novel form of the self-locking inter-module connection,its mechanical behavior is still unclear.For this reason,this paper investigated the seismic performance and force transmission mechanism of the connection through experimental study,numerical simulation and theoretical analysis.The specific work and critical findings are as follows.(1)Four sets of full-scale hysteresis tests on the self-locking connection were completed,taking into account the effects of the inter-module connection forms,the spacing between twin-beams,and the modular beam section forms,respectively.The seismic performance of self-locking connection in terms of failure mode,load carrying capacity,stiffness degradation,ductility and energy dissipation capacity,deformation and strain distribution were obtained.The effects of the parameters on the seismic performance of the structure have been analyzed.The result show that the self-locking connection have excellent seismic performance.(2)Numerical simulations of specimens with self-locking connection were performed using ABAQUS,and the finite element model was verified by comparing with experimental results.Parameters such as wall thickness of corner fittings,twinbeams spacing and axial pressure ratio were selected for parametric analysis.The results show that the side-wall thickness of the corner fittings has a significant effect on the mechanical properties of the structure.The effect of the top-plate thickness of the corner fittings is not significant.The twin-beams spacing has little effect on the carrying capacity of the structure.The axial compression ratio is the key factor affecting the failure mode of the structure.(3)A simplified finite element model based on beam units and connectors for self-locking inter-module connection was developed.Based on the simplified finite element model,a simplified mechanical calculation model was established,and the formula for calculating the bending moment of the inter-module connection was derived and verified.The factors affecting the bending moment transfer capability of the inter-module connection were revealed by parametric analysis.The conclusions obtained can be applied to column-connected inter-module connection of the same type as the self-locking connection.