Flexural strength of concrete bridges prestressed by external tendons

The ultimate capacity of beams with external prestressing cables slipping at the saddle points cannot be evaluated by a local analysis of the critical sections and a nonlinear analysis of the whole structure is required. In this work a new simplified method derived from a rational approach is proposed for evaluating the traction increment in the cable and consequently the flexural strength of the beam. The proposed expression has been tested in a wide range of cases with practical interest and it has furnished more accurate results with respect to formulas previously proposed in literature and practical codes.