Experimental and Finite Element Analysis of New Type of Cross-Shaped Gusset-Plate Support Connections to Slotted Tubular Memebers

In order to investigate the mechanical properties and failure mechanism of the new type of gusset-plate connections to slotted tubular members, four specimens of this kind of joint were designed for monotonic static loading test. The test parameters studied included plate thickness and load form. The failure mode, joint ultimate bearing capacity of joint, joint displacement and strain distribution of different parts of the joint (circular tube, transverse gusset-plate and vertical gusset-plate) were discussed. The structural parameters affecting the performance indexes of joint specimens (tube wall thickness, tube diameter, plate thickness and number of branches) were analyzed by finite element parametric analysis. Results indicated that there were two types of joint failure modes, gusset-plate failure and tube failure, under the action of axial load on tube; the relative relations between tube wall thickness and gusset-plate thickness mainly determined the plastic deformation capacity of joints. For the joint specimens with two branches, when the thickness of the gusset-plate was greater than that of the tube wall, the specimen failed at the junction of the circular tube and gusset-plate, and this damage was ductile failure; when the thickness of the gusset-plate was less than that of the tube wall, the specimen bent or broke at the bottom of the gusset-plate, and this damage was brittle failure. For the joint specimens with four branches, the gusset-plate thickness should be 2 times the tube wall thickness to ensure the plastic development and ultimate bearing capacity of the joint.