In the past, particularly in severe environmental conditions, prestressed concrete beams have shown non-negligible phenomena of corrosion of the prestressed reinforcement. Owing to the modification of the mechanical and physical properties of steel, corrosion of the prestressed reinforcement has generally led to a reduction of the maximum axial force sustainable by steel and to a degradation of the bond resistance between steel and concrete. This problem has occurred with reference to posttensioned tendons more frequently than for pre-tensioned strands. The higher sensitivity of posttensioned tendons is caused to a great extent by the mode of protection of the prestressed reinforcement, which is carried out in situ by injecting grout into the sheaths of the tendons after prestressing of steel. In the light of the above-mentioned considerations, the present paper proposes a design procedure for prestressed concrete beams which takes account of the effects of corrosion of the prestressed reinforcement on the ultimate capacity of members subjected to the contemporary action of flexure and shear. A simple numerical procedure for the evaluation of the flexural-shear domain, already presented with reference to reinforced concrete cross-sections, is applied to a prestressed concrete beam with the aim of pointing out the possibility of a design method which considers in advance the effects of corrosion.
Influence of corrosion of prestressed reinforcement on the flexure-shear interaction
RECUPERO, Antonino;
2005-01-01
Abstract
In the past, particularly in severe environmental conditions, prestressed concrete beams have shown non-negligible phenomena of corrosion of the prestressed reinforcement. Owing to the modification of the mechanical and physical properties of steel, corrosion of the prestressed reinforcement has generally led to a reduction of the maximum axial force sustainable by steel and to a degradation of the bond resistance between steel and concrete. This problem has occurred with reference to posttensioned tendons more frequently than for pre-tensioned strands. The higher sensitivity of posttensioned tendons is caused to a great extent by the mode of protection of the prestressed reinforcement, which is carried out in situ by injecting grout into the sheaths of the tendons after prestressing of steel. In the light of the above-mentioned considerations, the present paper proposes a design procedure for prestressed concrete beams which takes account of the effects of corrosion of the prestressed reinforcement on the ultimate capacity of members subjected to the contemporary action of flexure and shear. A simple numerical procedure for the evaluation of the flexural-shear domain, already presented with reference to reinforced concrete cross-sections, is applied to a prestressed concrete beam with the aim of pointing out the possibility of a design method which considers in advance the effects of corrosion.Pubblicazioni consigliate
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