Mechanical Behavior of Steel-Concrete Joint in a Bidirectional Curved Pylon of a Long-Span Cable-Stayed Bridge

The complex mechanical behavior of a steel-concrete joint (SCJ) in a bidirectional curved pylon of a cable-stayed bridge is investigated using finite-element analysis (FEA) and a 1:4 scaled full-section model test. Formulas for the stress distribution and stress nonuniformity coefficients of the concrete in the SCJ are proposed to evaluate the force transmission characteristic of the SCJ. The FEA results indicate that variations in the section stiffness at both the bearing plate and the end of the steel structure result in abrupt stress changes and distinct spatial force characteristics of the SCJ. The experimental results reveal that the SCJ exhibits better force resistance than the concrete and steel transition segments, and the force transfer is dominant through the bearing plate. The proposed formulas are validated by using the measured results, which reveal significant nonuniformity in the stress distribution. The stiffness variation at the bearing plate, nonuniform concrete stress distribution, and spatial force characteristics should be considered during the design of similar SCJs in spatial pylons.