Experimental investigation of force transmission performance in joint of steel truss web member-concrete composite truss arch

To investigate the bearing capacity of a novel steel truss web member-concrete composite arch joint, and to provide a basis for arrangement of shear connectors of the joint, tests were conducted on four joint specimens with different shear connectors based on the engineering background of the Wumengshan Bridge. The failure modes and bearing capacity of the joint specimens were examined. The force transmission performance of the different shear connectors was comparatively analyzed. The applicability of existing code-based methods for calculating the bearing capacity of the shear connectors was comparatively analyzed. The analytical results show that all joint specimens exhibit buckling failure in the compressed web members and the gusset plates at the connections of the compressed web members. The interfacial bonding between the gusset plate and the concrete remains intact, with no signs of failure observed. All joint specimens exhibit bearing capacities exceeding twice the design load, thereby meeting the design requirements. The shear connectors effectively transfer the axial force from the steel chord, which is applied by a web member, to the concrete chord, and the most significant force transmission occurs within a range equal to one width of web member below the joint center. Penetrating steel bars present a superior force transmission performance compared to studs, and the difference in force transmission between a specimen with only penetrating steel bars and that with both penetrating steel bars and studs is very small. The recommended specifications applicable to the calculation of shear bearing capacities of penetrating steel bars and studs are presented. The research findings can provide reference for the design of steel truss web member-concrete composite truss arch joints.