Resistance of Welded Joints of Concrete Filled Steel Tubular Truss Girders

Structures of circular hollow steel section (CHSS) with concrete filled in chord tube have been increasingly applied in bridge engineering. Simply welded joints of concrete-filled steel tubular (CFST) bridges are traditionally designed with formulae for CHSS joints, which disobeys with the inherent advantages of CFST structures. Furthermore, due to the discrepancy of loading conditions between bridge and other structures, geometric dimensions and structural configurations of simply welded joints in bridge have a little difference from and sometimes fall out of the proposed application range in existent structural CHSS joint design codes. In order to verify structural design of simply welded joints in bridge, experimental study on simply supported CHSS, CHSS-CFST and CFST truss girders were carried out. With investigation about the overall bearing capacities and collapse mechanism, potential joint failure modes of CFST truss girders were generalized and appropriate design methods with traditional structural codes for CHSS joint were proposed.