Jacketing of reinforced concrete columns subjected to axial load

This paper investigates the suitability of two existing confined concrete models, based on the concept of an effectively confined concrete core, to predict the behaviour of jacketed reinforced concrete columns when subjected to axial loads. Two types of jacketing with reinforced concrete (RC) were studied: full-length and partial jacketing. Consideration is also given to variations in the properties of the different concretes used in the jacket and the original column. Existing experimental data show that jacketing of RC columns using reinforced concrete enhances the axial load-carrying capacity, strain at peak axial load and post-peak ductility. However, conventional methods of analysis underestimate both the peak axial load and the corresponding strain. The two models were used to predict the entire load–strain relation of jacketed RC columns subjected to axial loading. The predictions agree well with available test results. For columns subjected to patch jacketing with only one set of stirrups, the predicted peak loads showed good agreement with experimental results. However, the corresponding strains were overestimated by as much as 20%.