Finite element modelling of steel-caged RC columns subjected to axial force and bending moment

Abstract

Steel caging is an effective, economical, easily applied and widely used method of strengthening RC columns. Based on the results of two experimental studies, this paper proposes the finite element modelling of RC columns strengthened by a steel cage under axial loads and bending moments. The FE models were used to obtain the N-M diagrams of experimental cases in which a study was made of the improved resistance of RC columns strengthened with this type of strengthening technique. The paper also includes a comparison of different methods of connecting the cage around the beam–column joint and a parametric study to observe the influence of diverse parameters on the behaviour of the strengthened column, including: angle dimensions, number of strips, the yield stress of the steel used in the strengthening, the dimensions of the capitals at both ends of the column, concrete strength and the characteristics of the reinforcement used in the columns. Finally, the results of the various tests (experimental and numerical) described in the paper are used to be compared with three design proposals and the goodness of fit of each one is analysed.