Aseismic Behaviour of Tube Thickness Reinforced Completely Overlapped Tubular Joints

摘要

For penetrately welded tubular structures, both high stress concentration and residual stresses exist at the brace/chord intersection region. Due to this reason, brittle fracture failure may occur along the weld toe when a tubular structure is subjected to cyclic loading, such as earthquake load. To improve the aseismic behaviour of welded tubular structures, a new type of tubular joint, namely tube thickness reinforced completely overlapped tubular joint, is presented. For this joint type, one brace member is welded onto the outer surface of another brace to avoid the failure occurring on the chord surface. The joint of the two braces is then reinforced by increasing the tube thickness so as to move the failure position to the overlapped gap. Such measure can transfer brittle fracture failure of the joint to ductile shearing failure of the gap, and thus to improve the capacity of the earthquake resistance of the tubular structures. Using finite element analysis, the bearing capacity and the hysteretic behaviour of conventional and modified tubular joints are analyzed. Numerical results show that the proposed tubular joint is advantageous in resisting cyclic loading.