Numerical Simulation on Mechanical Properties of Single⁃Sided Bolted Inner Sleeve Connection Joints Between Steel Modular Units

In order to promote the widespread application of modular steel structures in practical engineering and solve the comprehensive problems of weak connection performance of connectors， difficulty in bolt installation， and difficulty in ensuring welding quality during beam-column welding in the existing forms of joint connections between modular units， this paper proposes a type of joint design for steel modular units using single-sided bolts and inner sleeves. This joint mainly consists of inner sleeves， high-strength single-sided bolts， square steel pipe columns， H-shaped steel beams， etc. By using ANSYS finite element simulation software to perform quasi-static and low-frequency reciprocating loading on the four established connection modes of joints， the failure modes， bending moment capacity， hysteresis curve， skeleton curve， and energy dissipation performance of the four nodes were analyzed. Finally， referring to existing structural engineering， the mechanical performance parameters of the joints obtained from the research were assigned to the overall multi-layer steel structure model established by MIDAS/Gen， and the structure was subjected to dead loads， live loads， wind loads， and seismic actions to further explore the connection performance of joints within the overall structure. The results showed that when a single-sided extended end-plate was used in the floor beam， the bending capacity of the joint increased by approximately 8.32%. When intermediate connecting bolts and cover plates were used， the bending capacity of the joint increased by approximately 16.61% and 10.33%， respectively. When the flush end plates were used， the hysteresis curves of the joint significantly exhibited pinching phenomenon， significantly reducing energy dissipation performance. The connection performance of this joint not only met the requirements of existing specification（GB/T 50011‒2010） but also exhibited good energy dissipation performance， meeting the requirements of multi-layer pure modular steel structures up to 8 stories.