Torsion resistant Design in Curved Box girder Bridges with External Tendons

Abstract:

In order to resist torsion effect to improve the stress state in curved box girder bridges, the torsion resistant design method of applying external tendons without increasing tendons is proposed. Based on the space analytic geometry relationship, the externally prestressing torsion calculation formulas are derived out. The torsion resistant design process of applying external tendons is presented with the objective of minimizing torsion. The optimal parameters of horizontal alignment of tendons are solved with non linear optimization method at the end of the process. The results indicate that the reasonable space layout design of external tendons instead of internal tendons significantly reduces peak torsion, and has almost no impact on the bending and shearing capacity. Comparison with the finite element analysis shows that the numerical results calculated by the formulas agree well with the finite element analysis, therefore the formulas can be a simple approach for practical design.