Cyclic and monotonic behavior of strengthened and unstrengthened square reinforced concrete columns

The use of composite materials is an effective technique to enhance the capacity of reinforced concrete columns subjected to seismic loading due to their high tensile strength. In this paper, numerical models were developed in order to predict the experimental behavior of square reinforced concrete columns strengthened with glass fiber reinforced polymer and steel bars and unstrengthened column under cyclic and monotonic loadings, respectively. Two columns were modeled in the present work. The first concerns the column without strengthening subjected to lateral monotonic loading, and the second concerns the column strengthened with glass fiber reinforced polymer and steel bars subjected to lateral cyclic loading. Comparison of the numerical modeling and the experimental laboratory tests results were performed and discussed. Good accordance between the numerical and experimental force-displacement responses was obtained. Improvement of the strength of the reinforced concrete column subjected to cyclic loading was described with comparison of the behavior of the strengthened column with the unstrengthened reference column. The results show a good improvement in the load carrying capacity and ductility of the column. The main objectives of this numerical modeling are to contribute to the comprehension of the monotonic and cyclic behavior of the square reinforced concrete columns and to compare the numerical results with the experimental ones.