Numerical modelling of the behaviour of steel-confined rc columns

The use of steel plates externally glued to RC members is still an efficient solution due to relatively low costs, ductile stress-strain behaviour, simple and fast mounting with possible removing and reuse of the material. Many applications for flexural and shear strengthening can be realized but a typical intervention is the transversal confinement with angles and strips to increase the axial load capacity of columns. However, the design provisions for this application are still lack even if specific rules are necessary because the confinement effect can be strongly influenced by the amount and geometric configuration of the external steel. In this paper a detailed 3D FE model of RC columns confined with external steel plates is proposed. The model is firstly calibrated on available experimental results available in the scientific literature obtaining a good agreement of the loading capacity. The influence of the perfect bond between the steel angles and the RC column is evaluated too. Finally, the model is used for considering the variation of the steel configuration in terms of strips spacing and thickness of the steel elements.