Time-dependent creep and shrinkage analysis of curved steel–concrete composite box beams

Curved steel–concrete composite box beams are widely used in urban overpasses and ramp bridges as they are light in weight, have large spanning ability and high torsional rigidity. One-dimensional models are generally used to analyze bridge performance due to their calculation and numerical efficiencies. An incremental step-by-step method based on the Kelvin rheological model together with a discrete algorithm in finite element space is adopted in this study to analyze the mechanical behavior of curved composite box beams. A model with a beam finite element with 26 degrees of freedom (DOFs) is proposed for curved composite box beams that considers the constrained torsion, distortion, shear lag, biaxial slip at the interface and time-dependent effects. Furthermore, the experimental results of the long-term loading tests of three curved composite box beams are selected to validate the proposed beam element model. Finally, the proposed model is applied to analyze the long-term behavior of a curved composite box beam that is used in real engineering applications.