Axially loaded RC columns strengthened by steel cages

Steel caging is routinely used to strengthen reinforced concrete (RC) columns in many countries. This paper studies the behaviour of RC columns strengthened by this technique. Following the results obtained from an experimental study, all the specimens are modelled by the finite-element (FE) method. After verifying the FE models, a parametric study is carried out, determining how variations in the parameters affect the behaviour of the strengthened column. FE models are used to compare the ultimate load of RC columns strengthened by steel cages with that obtained from two design rules, showing one of them very conservative and in good agreement with the other. This proposal can be used with confidence for design, since the results obtained are slightly conservative.