Mechanical performance of SLO joints for single-layer reticulated shells under bending shear and axial eccentric loading conditions

The mechanical behavior of the SLO joint with a separated joint body is investigated under bending shear and axial eccentric loading. The validity of the finite element model of the SLO joint is verified through a comparison with pure bending test results. Six groups of joints with varying parameters are designed to analyze the effects of end plate thickness, bolt size, axial eccentricity, and lever arm on the mechanical performance. The failure mode of the joint under axial eccentric loading is obtained. The following conclusions are obtained: under the action of axial eccentric force, the axial eccentricity has little impact on the initial rotational stiffness of the joint, but a significant impact on the ultimate bending moment. Under shear bending, the thickness of the end plate has little effect on the initial rotational stiffness and ultimate bending moment of the joint. But as the bolt size and lever arm increase, the initial rotational stiffness and ultimate bending moment of the joint both increase. The calculation formulas for initial rotational stiffness and ultimate bending moment under axial eccentric and bending shear actions are derived by introducing stiffness ratio and moment ratio based on pure-bending formulas. The formulas proposed in this study can be applied to the design of SLO joints with the separated joint body.