Stiffness of corroded partially prestressed concrete T-beams under fatigue loading

To study the evolution of the performance of prestressed concrete beams under the combined effect of corrosion and fatigue, static and fatigue loading experiments of seven partially prestressed reinforced-concrete T-beams are carried out. The results show that brittle failure, marked by longitudinal steel bar fracture at the main crack, occurred under fatigue loading. With an increase in the maximum applied fatigue load and the corrosion degree of the longitudinal steel bar, the fatigue life of the test beam is abruptly shortened, the mid-span deflection growth rate is gradually reduced and the brittleness is more significant. A calculation method for the stiffness and deflection of the corroded partially prestressed concrete that considers the stress redistribution between the prestressing strand and steel bars during fatigue, the fatigue damage of concrete, the corrosion and fatigue damage of steel bars, and the contribution of the tensile force to the stiffness of concrete is proposed. The error between the calculated and experimental results is less than 10%. The research results of this paper can be applied to predict the deflection of an actual bridge structure under fatigue loading in a chloride corrosion environment.