Mechanical performance study of a novel modular gymnasium inner sleeve all-bolt cross connection joint – part Ⅰ: Experiments and finite element modeling

The authors propose a novel movable modular gymnasium based on modular building technology to meet people's sports needs. However, the huge roof load puts higher requirements on the performance of modular units and their connecting joints. In light of this, the authors propose a novel connection joint using the inner sleeve and bolted connections, which connect the upper and lower columns of the modular unit to give it higher performance. In addition, it connects the upper and lower beams of the modular unit by bolts to improve its overall performance. The authors evaluated the mechanical properties of the connecting joints through experiments and simulations. The results indicate that the welding quality determines the beam-oriented bearing capacity of the connections while having little impact on the column-oriented bearing capacity. It is difficult for the inner sleeve to enhance the initial stiffness and beam-oriented bearing capacity of the joints due to the initial gap between the inner sleeve and the modular column. The restraint effect of the stiffening ribs induces the deformation of the inner sleeve, and its bearing capacity increases up to 91%. The inner sleeve improves the column-ward bearing capacity and deformation capacity of the joints, and its bearing capacity rises to 135%.