A Unified Approach for a Pseudo Nonlinear Analysis of Partially Prestressed Concrete Beams Containing a Combination of Bonded and Unbonded Tendons

18.Oct.2025

​​A rational yet generalized pseudo nonlinear analysis method is proposed for the prediction of the stress increase at ultimate in the prestressed reinforcement, Δf ps, of simply supported partially prestressed concrete beams with bonded and/or unbonded tendons subjected to static loading. The proposed procedure complies with international codes and further addresses cases where beam strength is underestimated using empirical equations or where effective prestress, f pe, is less than one-half the ultimate strength, f pu. It is a first to establish force equilibrium and relevant constitutive relationships to solve three nonlinear equations simultaneously with three unknowns; namely, Δf ps in bonded steel tendons, Δf ps in unbonded steel or CFRP tendons, and neutral axis depth, c. To account for the lack of bond in beams with unbonded tendons, a bond reduction coefficient derived from past studies using rational …​