Experimental investigations on strengthened reinforced concrete columns under monotonic axial loading

Strengthening of the existing reinforced concrete (RC) column is nessesary to enhance their axial load-carrying capacity or ductility. This paper presents the results of an experimental study relating to the performance of reinforced concrete columns strengthened with different techniques such as the steel angle, steel straps, and ferro-cement under pure axial load. A total of six square short reinforced concrete columns were constructed. The cross-section and height of tested columns are 150×150 mm and 1.2 m, respectively. Two specimens were set as the control columns (without strengthening). The other four reinforced concrete columns were strengthened with different techniques. Two columns are strengthened with four steel angles at each corner of the column confined with prestressed steel straps. Another two columns are also strengthened with four steel angles confined with prestressed steel straps and ferro-cement. The experimental results are reported in terms of the load-deformation curves as well as the failure modes. A significant enhancement of the maximum axial load-carrying capacity and the ductility is observed for the strengthened reinforced concrete columns. Finally, the discussion of the use of different strengthening techniques is also carried out in this paper.