Experimental tests on corroded prestressed concrete beams subjected to transverse load

摘要

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.