Experimental Research on Bending-Torsion Characteristics of Steel-Concrete Composite Box Beams

Abstract

Due to the axial curvature and the eccentric vehicle loads, bending-torsion couple effects will be generated in the curved steel-concrete composite box beam bridges. To study the bending-torsion couple characteristics, six steel-concrete composite box model beams are tested under the bending-torsion couple loads, with the initial torsion-bending ratios and shear connection degrees as the design parameters. The ultimate bearing capacity, section strain, and interfacial slip of the steel-concrete composite box beams are measured. The test results show that, the fully connected composite beams mainly express bending or bending-torsion failure modes, but the partially connected composite beams are mainly sliding failure modes. The existence of the torque doesn’t have great influence on the ultimate bearing capacity and bending moment of the composite box beams. Under the bending-torsion couple loads, there are not only the longitudinal slip between the steel girder and concrete slab of the composite box beam, but also the transverse slip perpendicular to the beam axis.