Abstract
The parametric study using FEM and the experiment of T-beams prestressed with external tendons have been performed to investigate the factors thought to influence on the shear mechanism of externally prestressed concrete beams. The effects of prestressing force and stirrup can be observed as important factors to the failure mechanism. The simplified truss model, having a small number of degrees of freedom, has been modified and proposed by adapting the formulation to predict the angle of concentrated stress flow and the thickness of diagonal compression members for evaluating the shear carrying capacity of externally prestressed concrete beams. The predicted results show the good agreement with experimental results.