Experimental Test on Square Concrete Columns Strengthened with CFRP Composites in Different Configurations

The shape and FRP configuration of the concrete columns can straight forwardly influence the efficiency of the FRP confinement. Most of the columns shape in concrete buildings are non-circular sections, therefore, special attention need to be given to their strengthening and rehabilitation to maintain the safety of buildings infrastructure especially, for rectangular/square sections with section depth ≥ 300mm. This paper is directed towards to this objective through an experimental investigation carried out on 8 square concrete columns having the same dimensions (300 × 300 × 1000) mm (width × depth × height respectively) with low concrete strength confined with different CFRP configurations. Two of the columns left without CFRP strengthening to be as a control specimens, two specimens were strengthened with two-layers of CFRP sheets (full confinement), two specimens were strengthened with two-layers of CFRP sheets and CFRP strips combined with CFRP anchors, in addition, one specimen was strengthened with one-layer of CFRP and CFRP strips combined with CFRP anchors, finally, the last specimen was strengthened with CFRP strips combined with CFRP anchors (partial confinement). The results revealed that CFRP composite wrapping in different confinement procedures can enhance the ultimate load capacity and ultimate compressive strength of square concrete columns having low compressive strength subjected to axial load, and the anchorage system improved based on the final failure mode of confined columns where the failure didn’t happen in the anchors zones, which was an aim of the research.