Experimental and theoretical study on the bearing capacity of FGC joints for single-layer aluminium alloy lattice shell structures

Gusset joints connect only the upper and lower cover plates to the flange of aluminium alloy beams through bolts, and there is no connection to the web. To compensate for this deficiency of gusset joints, a new aluminium alloy flower-gusset composite joint (FGC joint) is proposed in this paper. In this paper, compression, shear and bending tests are performed on new FGC joints. The test results show that (1) compared with those of gusset joints, the compressive stiffness and bearing capacity of FGC joints increase by 2.1 and 1.36 times; (2) the shear capacity and shear stiffness of FGC joints are 1.47 times and 1.74 times higher than those of gusset joints; and (3) the bending capacity of FGC joints is 1.2 times higher than that of gusset joints, but the bending stiffnesses of the two kinds of joints are similar. Then, a numerical model is established to analyse the load transfer mechanism of FGC joints. Numerical analysis shows that the FGC joint passes axial compression through the cover plates and the flower body, shear is transmitted mainly through the flower body, and the bending moment is mainly transferred by the cover plates. Finally, based on the test and numerical analysis, the bearing capacity design method of the new joint is proposed through theoretical analysis.