Experimental Study of Hollow Slender Reinforced Concrete Columns Subjected to Eccentric Loads

This paper was focused on the investigating on the behavior of hollow slender reinforced concrete columns subjected to the axial loads. A total of seven specimens were designed as slender reinforced columns and these were divided into two groups. Each column is symmetrical and had a rectangular cross section of 140 × 80 mm and 2000 mm in length. The column was reinforced by 6Ø6mm for longitudinal reinforcement and Ø6@6 mm bars were used for transverse reinforcement ties. The effect of strengthening by CFRP sheet on the buckling of column, eccentricity 20, 40 and 120 mm and opening shape were studied. The results showed that the strengthened columns by CFRP caused an in the ultimate load CFRP were 26.3 % and 76.3 % for strengthened lengths of L/4 and L respectively compared with the un-strengthened column. The ultimate load of columns is reduced with existing the load eccentricity and amount of losses in strength increased with increasing the eccentricity. Also, it was found the hollow columns having circular holes had better performance compared to hollow columns having rectangular hole