Experimental Research and Finite Element Analysis of Axial Compression Behavior of Joints on Offshore Platform Between Composite Structure and Steel Tube

To solve the reliability problem of joint connection between upper desk and lower blocks on stainless steel-concrete-steel tube offshore platform, three types of joints were put forward based on JZ20-2 offshore platform including transitional connector joint, stiffened bearing plate joint, and flange joint. Three 1/4 scale model joint specimens were designed and the static tests were performed to study their axial compression mechanical properties. Nonlinear FEA of the specimens was performed by ABAQUS as well. Both experimental and finite element analysis results show that three types of joints can well satisfy the capacity design requirements of the offshore platform. Among them, the flange joint has the highest bearing capacity and the stiffened bearing plate joint has the best ductility. In addition to the flange joint, other joint specimens are seriously damaged. The failure modes of the specimens are mainly reflected in the buckling damage of transitional connector, steel tube, bearing plate and stiffeners. The appearance of stainless steel-concrete-steel tube is almost complete through the whole tests, which indicates that there is still a surplus of bearing capacity.