Experimental tests on corroded prestressed concrete beams subjected to transverse load

Abstract

In prestressed concrete beams, the stress level of tendons drastically modifies the steel corrosion process. Stress corrosion is characterized by the coupling between the conventional corrosion and the steel microcracking. Also, for a low corrosion level of the tendon and under normal service loading, the steel microcracking can lead to a brittle failure. An example of PC structure failure is the Santo Stefano viaduct built in 1954, along the coast of the Mediterranean Sea, in Sicily (Italy). In this scenario, an experimental campaign on corroded prestressed concrete beams is carrying out at the University of Messina (Italy). The goal of the research project is the influence of tendon corrosion on the response behavior of structural elements subjected to transversal load. In 2006, a set of prestressed concrete beams was casted at University of Messina Laboratory. Some defects were artificially induced in each specimen by introducing chemical solution or acid in the duct. Then, different damaging fluids were used to induce a prestressed tendon weakness and the specimens were maintained in the basement of the laboratory. In the last year, a destructive test campaign has been started to investigated the degradation of the load‐bearing capacity of beams due to the corrosion progression. In this work, the experimental results of the first group of tests, in terms of crack pattern and load‐deflection response, are reported and commented.

Numerical evaluation of the corrosion effects in prestressed concrete beams without shear reinforcement

“…Both numerical approaches are validated by the means of the comparison with experimental results of the VIGA 470 beam tested at the "Instituto de Ciencias de la Construcción Eduardo Torroja" in Madrid. 26 The VIGA 470 is one of the 14 naturally corroded prestressed beams coming from a natural gas power station and characterized by nonuniform corrosion (pitting) induced by chlorides. The numerical analyses are conducted using the PARC_CL 2.1 crack model developed at the University of Parma, 30,31 considering the spatial distribution of the corrosion pattern provided by experimental evidences.…”

“…Although PC structures have been largely diffused in the last 50 years, above all in infrastructures of strategic importance, as viaducts and bridges, the theme of corrosion of these structural typologies is still under investigation and rigorous guidance is not accepted in spite that European Manuals with some guidance rules have been published more than 20 years ago 24–25 . Furthermore, tests on natural corroded beams are rare in literature 26 and often there is no detailed information on the spread of corrosion along the length of the strands. Finally, no data are available in literature concerning the study of corroded prestressed beams without transversal reinforcement, with the exception of papers published by authors 27…”

“…In particular, two modeling strategies of strands are adopted in order to understand how much the bond affects the result: the smeared and discrete approaches. Both numerical approaches are validated by the means of the comparison with experimental results of the VIGA 470 beam tested at the “Instituto de Ciencias de la Construcción Eduardo Torroja” in Madrid 26 . The VIGA 470 is one of the 14 naturally corroded prestressed beams coming from a natural gas power station and characterized by nonuniform corrosion (pitting) induced by chlorides.…”

Experimental tests on shear capacity of naturally corroded prestressed beams

“…Rinaldi et al 10 carried out four‐point bending tests on nine artificially corroded PC beams and pointed out that corrosion affects the ultimate flexural capacity, the failure mode and finally the structural response of PC beams. Recupero et al 11 tested a set of prestressed beams artificially corroded. In this paper, the results of an experimental campaign, which investigates the shear capacity of corroded PC beams, are illustrated.…”

Experimental research and mechanical analysis on the bond‐slip behavior between concrete and corroded I‐shaped steel

“…However, a lot of work has been historically carried out to investigate the impact of corrosion on the rebar. Abundant achievements have been made in the following four aspects: (1) the law of bearing capacity degradation caused by reinforcement corrosion [8][9][10][11][12][13] ; (2) the law of bond strength degradation caused by reinforcement corrosion [14][15][16][17][18] ; (3) the average bond stress-slip relationship of corroded reinforced concrete 14,15,19,20 ; (4) reparation of corroded reinforced concrete through different materials. [21][22][23] The rebar is corroded, its own strength is reduced and the bond is degraded, resulting in a reduction in the bearing capacity from above mentioned research.…”