COMPRESSION CAPACITY OF RC COLUMNS STRENGTHENED WITH LONGITUDINAL CFRP COMPOSITE

In the present research, carbon fiber reinforce polymer (CFRP) composite with fibers aligned along the column axis was used to strengthen the RC columns. A newly introduced method named as grooving method (GM) was utilized to improve the compressive behavior of longitudinal FRP and postpone the buckling and delamination of longitudinal composite from concrete substrate. Two techniques of GM, i.e. externally bonded reinforcement on grooves (EBROG, to be pronounced as /ebrΛg/) and externally bonded reinforcement in grooves (EBRIG, to be pronounced as /ebrIg/) was used, as well as EBR method, to strengthen the column specimens. For this purpose, 11 RC column specimens with circular section of 150 mm diameter and height of 500 mm were tested under uniaxial compression. Experimental results showed that using the grooving method in strengthening the column specimen, significantly increased the load carrying capacity of specimens; while the conventional EBR method showed inconsiderable effects on the load capacity. The results demonstrated that utilizing EBROG and EBRIG techniques led to respectively 14.1% and 18.5% increase in the column maximum load. However, the column strengthened with EBR method indicated only 2.6% increase in the load carrying capacity.