Investigation the behavior of concrete-covered steel columns and retrofitting it with carbon polymer fibers under simultaneous axial loading and reciprocating lateral loading

The application of composite sections in recent years is increasing because of its great advantages in advanced countries.The purpose of this study is to investigate the effective parameters on loading capacity of steel columns covered with concrete under the simultaneous impact of axial and cyclic lateral loading, including steel compound shape, concrete strength and retrofit with carbon polymer fibers. The use of a concrete-covered steel column in comparison to a single steel column or reinforced concrete column will increase the capacity of the final capacity significantly. In other words, composite columns have a very high load capacity. for this purpose, in order to study the behavior of steel columns covered with concrete under the simultaneous effect of axial and cyclic lateral loading, After validating the modeling in abaqus finite element software, the behavior of these columns in different cases of steel composite section, 28 day compressive resistance of a different concrete, and impact of retrofitting with carbon polymer fibers on ultimate capacity, is investigated. the results show that the parameters such as the shape and dimensions of section of steel column, the 28 - day compressive resistance of a different concrete and retrofitting with carbon polymer fibers have a significant effect on increasing or decreasing the ultimate capacity of these columns. Finally, the cracking pattern in the concrete has been investigated and due to the crack propagation pattern, retrofitting with carbon polymer fibers have been applied on the concrete surface to reduce corrosion crack.