Experimental study on residual strength of concrete confined with corroded stirrups

Corrosion of steel bars is a serious issue compromising the reliability of reinforced concrete structures. Previous research has proven that confined concrete has increased confined strength, ductility, energy dissipation capacity, etc. However, existing confined concrete models cannot accurately predict the strength and stress-strain relationship of concrete confined with corroded stirrups. This paper presents an experimental study on the behavior of eight square columns confined with stirrups damaged by accelerated chloride corrosion. The weight loss of the stirrup ranges from 5% to 31.7%. The stress-strain curves of confined concrete are obtained from the concentric compression loading tests. Based on the well-established Mander model, modification factors are introduced to account for the effect of corrosion on the confined strength, confined strain, and descending branch of the curves. These modification factors predict the constitutive relationship of concrete confined with square stirrups as a function of the weight loss and localization levels of corrosion.