BEHAVIOR OF REINFORCED CONCRETE COLUMNS STRENGTHENED WITH PRESTRESSED STEEL JACKETS

Behavior of rectangular reinforced concrete columns strengthened with prestressed steel jackets was experimentally studied. In this research, the used steel jackets consist of four corner angles welded with steel ties under the effect of external prestressing forces. An experimental program consisting of fourteen half scale specimens of 1600 mm height and 150x300 mm cross sectional area was carried out to investigate the behavior of strengthened columns under axial compression forces. The main studied parameters were prestressing force level, length of steel corner angles, level of preloading of the specimen before strengthening, spacing between steel ties and size of corner angles. It was found that the proposed technique showed a considerable enhancement in each of capacity, stiffness and ductility of columns. An increase of 51%, 107% and 110% in capacity, stiffness and ductility, respectively, was obtained.