Investigation on Optimization of Cable Tension for Extradosed Cable-Stayed Bridge under the Rational Completion Stage

Abstract

The extradosed cable-stayed bridge is a new type of bridge developed in recent year. The main girder bears most of the load with its great stiffness, while the cable tension can improve the force state of the girder. So it is really necessary to optimize the cable force to determine the internal force of extradosed cable-stayed bridge under the rational completion state. But the optimization methods commonly used are based on the cable-stayed bridge and not entirely suit for the extradosed cable-stayed bridge. The paper puts forward a new optimization method, which includes applying the unknown coefficient functions aided by MIDAS/CIVIL, taking the reasonable feasible range of dead moment solved by stress balanced method as the constraint condition, making the square of unknown coefficients as objective function, and solving the cable force based on the effect matrix method thus to determine the cable force in reasonably completion state. This new method is verified with favorable effect, the internal force of this structure appear significant improvement. And finally, the results show better cable force obtained under the method in this paper compared with the cable force under other constraint conditions and objective functions.