CALCULATION FORMULAE OF STRESS CONCENTRATION FACTORS FOR CONCRETE-FILLED STEEL TUBULAR T-JOINTS UNDER OUT-OF-PLANE BENDING IN THE BRACE

摘要

CFST trussed arch bridge is a main type of CFST arch bridges in China. The arch ribs are composed of concrete-filledchord and hollow brace connected each other generally with full penetration butt welds to form CFST joint. The joint isthe weak part in the whole structure since the axial stiffness of the brace is much bigger than the radial stiffness of thechord. In fact, fatigue damage at the weld toe of the chord-brace intersection has been observed in existing bridges. Thehot spot stress (HSS) at the weld toe around the intersection, which should be used for the fatigue design of the joint, ismainly influenced by geometric parameters of CFST joint. However, their influence on HSS has not been formulated yetfor CFST joint.