Seismic retrofitting of reinforced concrete columns under cyclic loading by CFRP strips

In recent years the use of composite materials in various industries has been developed. A new and useful field in civil engineering is to apply of fiber reinforced polymer composite materials for strengthening and retrofitting of the reinforced concrete structures. Retrofitting of reinforced concrete columns by these materials causes to increase strength, ductility and flexural capacity. In this paper, both unconfined and confined concrete columns with composite carbon fiber reinforced polymer (CFRP) have been modeled by ABAQUS finite element software under constant axial loading and cyclic lateral loading.The FE results have been compared with the experimental results and analytical equations and a very good correlation has been obtained. Retroffited columns in this way resulted in a change in early shear mode to the flexural mode, reducing of column displacement in longitudinal and lateral directions in the plastic hinge region of the column, increasing of flexural capacity, increasing of ductility, increasing of axial compressive strength, increasing of column axial strain and increasing of rotational capacity at the joints.