Solid finite-element modeling of prestressed beams. Part II: Concrete girder-bridge with a parabolic tendon

The shear deformation in prestressed concrete girder-bridges under long-age conditions was studied based on the Timoshenko theory. Their shear deformation in terms of second-order effects is usually neglected. In this second article, an additional high-fidelity solid finite-element model using the Strand7, assuming geometric nonlinearities and time-dependent post–tensioning losses, was developed to analyze such a topic. A simply supported concrete specimen composed of parabolic tendon, significant slenderness ratio and high-strength concrete was considered. Based on the comparison with static tests performed on such a member, the shear deformation should firmly be assumed for gaining proper accuracies in most structural analyses, even when the concrete girder-bridges have an important length/height ratio. Similar to the first article, the solid finite-element model was then used to determine the parameters of the magnification factor formula. Accordingly, the post–tensioning identification, based on the “static deflected shape” method, requires considering the shear effect. Finally, the compression-softening theory was confirmed for concrete girder-bridges under long-age conditions when cracking is excluded and the second-order shear effects are < 10%.