Application of fiber reinforced polymers, (FRP), is effective in strengthening circular and
square reinforced concrete, (RC), columns. The efficiency of using FRP is considerably
reduced when wrapping rectangular columns. Experimental and theoretical investigations are
carried out to study the behavior of RC rectangular columns wrapped with FRP sheets under
cyclic lateral and axial loading. Eleven RC rectangular columns strengthened by FRP wraps
were tested under both cyclic lateral and axial loading. The main parameters investigated in
this research were volumetric ratio of FRP, spacing between FRP layers, axial load level, type
of FRP sheets, anchorage system of FRP and aspect ratio of columns. Finite element analysis
was carried out to predict the response of the tested columns. In addition, a simplified
approach, based on a developed numerical computer program, for predicting the curvature
ductility factor of FRP retrofitted columns subjected to cyclic loading is reported. The
approach was validated by comparing its results with those obtained experimentally. It is
concluded that behavior of rectangular columns subjected to cyclic lateral load is significantly
enhanced when wrapped with FRP. The proposed approach can be used to predict both the
ductility and strength of FRP wrapped rectangular columns.