This paper investigates the effect of cross-section aspect ratio and the effect of load eccentricity on the behavior of RC short columns with large-scale specimens wrapped with external carbon fiber polymers (CFRP) using finite element. Firstly, to study the effect of cross-section, six models have been conducted with various aspect ratios defined as the depth per the width of the crosssection with a constant number of carbon fiber layers. While the behavior of each aspect ratio in both axial and transverse directions was investigated, the results demonstrate that while the CFRP jackets increase the efficiency of square sections significantly, however, CFRP jacket's effect reduces when cross-section aspect ratio becomes more than 2.0. Secondly, twelve finite element models have been built to study the effect of load eccentricity on the behavior of RC short columns wrapped with external CFRP. The results showed that external confinement can significantly increase the strength of columns under concentric loading, while the enhancement in columns under eccentric loading is not the same.

This paper presents an experimental program to study the behavior of short high strength concrete composite columns subjected to either uniaxial or biaxial eccentric loading. The paper also includes a study on a suitable repairing technique for those columns by using carbon fiber reinforced polymers. The experimental program divided into two phases, the first consists of studying the behavior of six high strength reinforced concrete composite columns, three of them subjected to uniaxial eccentric loading as well as the other three subjected to biaxial eccentric loading, while the second phase deals with the behavior of five columns from the first phase after repairing them by carbon fiber reinforced polymers and subjecting them to the same eccentric loading. The main variables were the load direction, the number of sheets of carbon fiber reinforced polymers used and their arrangements. A comparison between the behavior of each column before and after repairing, using different numbers and arrangements of sheets of carbon fiber reinforced polymer layers was made. The comparison showed that wrapping composite steel columns with carbon fiber reinforced polymers is considered a very effective technique for repairing.