Load carrying capacity of RC compressed columns strengthened with steel angles and strips

In this paper a comparison between the analytical expressions for the prediction of the load carrying capacity of strengthened reinforced concrete (RC) columns with steel angles and strips is made. Expressions examined consider: the strength contribution due to the confinement effects induced by transverse strips; the composite action due to steel angles and unconfined concrete core; the strength contribution due to the composite actions of angles and concrete core taking into account that steel angles are subjected to axial force and bending moment and concrete core is confined by transverse strips. Design rules given by recent codes for the design of the strengthened columns are given. Therefore, results here generated, in terms of load carrying capacity, were compared with good agreement with experimental data available in the literature and with those obtained by using the existing models.

► RC columns strengthened with angles behaves as confined composite column.
► Load carrying capacity increases with size and dimensions of angles and strips.
► Buckling effects on steel angles depends on the slenderness of angles and on the stiffness of battens.
► Design rules for strengthened columns have to be respected to achieve strength and ductility.