ABSTRACT
Fixing a steel cage around a damaged or weak column, is a popular technique for strengthening R.C. columns in many countries. A numerical study on the effectiveness of the technique and the contribution of the involved concrete and steel elements is described in this paper. The ANSYS program which provides special capability of 3D nonlinear analysis of R.C. structures is used. It is assumed that no slip occurs at the interface of the concrete column and the steel angles, as it is usually adopted in a routine design in practice. However, since this assumption, is often not valid in real practice conditions, the reliability of the results are examined in the light of available experimental data. The technique is proved to be quite effective since the stresses in the weak concrete area are found to be low and the stresses adjacent to the steel angles are high. The contribution of the steel angles seems to be very significant. However a high level of stresses is developed at the concrete column corners, the highest being adjacent to the steel angle endings.
