CORRECTION TECHNOLOGY FOR MAIN GIRDER TORSION IN A COMPOSITE GIRDER CABLE-STAYED BRIDGE

To solve the problem of the steel longitudinal beam being unable to match precise installation of the steel main beam due to torsional deformation during the steel installation process of a composite twin-box girder cable-stayed bridge, a torsion correction method through the multipoint jacking adjustment of transverse steel beams is proposed. Based on the constrained torsion calculation theory for closed thin-walled members, a constrained torsion differential equation for steel longitudinal beams and its general solution were established. Then, the torsion angle and the jacking force on each steel beam at zero torsion angles were obtained. In addition, a local refined model by the finite element software Abaqus was established, simulating the jacking process with the transverse steel beams as a lever arm. The accuracy of the theoretical and numerical analysis was verified by the measured results on site. Results show that the torsion angle of the steel longitudinal beam could be adjusted through multipoint jacking of the steel crossbeam, the installation error caused by the torsion is effectively eliminated, and the efficiency and accuracy of the composite twin-box girder cable-stayed bridge are improved.