An experimental campaign was carried out on full-scale naturally corroded prestressed concrete (PC) beams without transverse reinforcement to investigate the corrosion effects on failure modes, shear capacity, and ductility. The analyzed PC beams, structural members of a thermal power plant, were subjected for 10 years to refrigerating wetting cycles with marine water. In this paper, the experimental results of four-point bending tests, carried out at the Institute "Eduardo Torroja" in Madrid, are described. Before tests, a visual inspection was conducted to detect the damages induced by corrosion. During the tests, displacements and strains were measured by using linear variable displacement transducer (LVDT) and digital image correlation (DIC). After the tests, strands were removed from beams and cut in pieces, which were weighed to measure the mass loss. Last, it was proved that the residual life of PC beams, exposed to chloride attack, is strongly affected by corrosion, whose effects reduce the shear capacity in terms of both resistance and ductility. K E Y W O R D S digital image correlation, natural corrosion, prestressed concrete beams, shear capacity 1 | INTRODUCTION In the last years, corrosion has been considered as one of the main factors that causes detrimental effects on durability and resistance of reinforced concrete (RC) and prestressed concrete (PC) structures and infrastructures. After the recent bridge collapses occurred worldwide, such as the Ynys-y-gwas Bridge in 1985 in

Corrosion of prestressed concrete structures causes size reduction of strands, degradation of mechanical properties of steel, cracking of the surrounding concrete, and bond decay at steel-to-concrete interface. In this paper, a numerical approach able to take into account all the effects involved in the corrosion process by using nonlinear finite element analysis (NLFEA) and membrane or shell elements modeling is proposed. Two different strategies are adopted to model strands: the smeared and the discrete approaches. The results obtained using these latter strategies are validated by comparing NLFEA results with experimental measurements of a naturally corroded prestressed beam tested at the "Instituto de Ciencias de la Construcción Eduardo Torroja" in Madrid. Finally, pros and cons of the proposed modeling approach are critically analyzed, demonstrating that considering the actual spatial corrosion distribution is necessary to predict the position where failure occurs.

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Existing reinforced concrete (RC) members, designed in accordance with obsolete codes, are often characterized by high stirrup spacing. The collapse mechanisms generated by high stirrup spacing are typically related to the buckling of longitudinal reinforcement and can be accentuated when corrosion takes place. In this paper, new refined material constitutive laws for steel, including inelastic buckling and corrosion of reinforcement, are implemented in a fixed crack model suitable for RC elements subjected to cyclic loadings called the PARC_CL 2.1 crack model. The effectiveness of the proposed model is validated through comparison with available experimental data and analytical predictions. Finally, the proposed model is used to calibrate correction coefficients to be applied to current codes formulation for the ultimate rotational capacity prediction of non-conforming elements subjected to buckling phenomena and characterized by corrosion of reinforcing bars.