Corroded Tension Chord Model: Load‐deformation behavior of structures with locally corroded reinforcement

Abstract

Localised corrosion may considerably impair the load-bearing and deformation capacity of reinforced concrete structures. The Corroded Tension Chord Model allows investigating the related effects. The model combines the effects of tension stiffening and strain localisation due to a local cross-section loss to calculate the load-deformation behaviour of tension members and entire structural elements containing locally corroded reinforcing bars on a sound mechanical basis. Based on simple equilibrium considerations, the critical loss of cross-sectional area is introduced, beyond which most of a reinforcing bar's ductility or a structure's deformation capacity, respectively, is lost. For conventional European reinforcing steel, even small cross-section losses may be sufficient to impair ductility drastically. Illustrative calculations on structural elements with various spatial corrosion distributions but identical mean cross-section loss reveal that the load-deformation behaviour strongly depends on the specific corrosion parameters: Structures with few heavily corroded reinforcing bars seem to be less critical regarding strength and deformation capacity than structures with many slightly corroded reinforcing bars.