Non-linear analysis of externally prestressed concrete beams

In an external prestressing system, there is no strain compatibility between the cable and the concrete at every cross-section, the increment of cable strain must be evaluated by taking into account the whole structure, rather than performing the calculation at each section, independently. In this study, a method for the calculation of cable strain, which is based on the deformation compatibility of beam and friction at the deviators, was proposed to predict entire response of externally prestressed concrete beams up to the ultimate state. Application of the developed method in numerical analysis of some examples was then performed. The predicted results showed that the structural behavior of externally prestressed concrete beams could be satisfactorily predicted from zero loading stage up to the ultimate loading stage. The proposed analysis reproduced experimental results such as deflection and increase of cable stress responses with remarkable accuracy.