Corroded Tension Chord Model (CTCM) for concrete structures with locally corroded reinforcement

Abstract

Many ageing RC structures suffer from severe localised corrosion of the reinforcing bars, particularly if exposed to chlorides. This damage affects strength and ductility: The cross-section loss of the reinforcing bars reduces the load carrying capacity, and the highly localised damage results in a localisation of deformations, which may severely impair the structure’s deformation capacity. A recent study at ETH Zurich investigated these effects on a sound mechanical basis, extending the established Tension Chord Model by corroded crack elements. This paper introduces the modelling concept of the resulting Corroded Tension Chord Model (CTCM) and presents the results of its application to structural elements with several corrosion spots. It reveals a significant decrease of the deformation capacity. Finally, an outlook on ongoing validation experiments is given.