AXIAL COMPRESSIVE BEHAVIOR OF SQUARE CONCRETE COLUMNS RETROFITTED WITH GFRP STRAPS

Concrete structures are very vulnerable to seismic hazard. Damages to these structures could be caused by the poor quality of materials used that do not meet the specifications, or due to excessive overloading, lack of planning criteria which do not conform with the standards, changes in the function of the building, besides due to the natural disasters such as earthquake. One of the efforts made to improve the capability of a reinforced concrete structure is to increase the strength and ductility of the members using Glass Fiber Reinforced Polymer (GFRP) jacketing. The fullwrapped GFRP jacketing is a method of retrofitting which is frequently implemented to the concrete columns to improve their strength and ductility. The aim of this study is to investigate the axial compressive behavior of square columns retrofitted with GFRP straps with various spacing of the straps. The results of the experimental study showed that the spacing of the straps affects significantly the strength and strain ductility of the concrete columns. The closer the spacing of the straps, the higher the strength and ductility of the columns