BEHAVIOR OF CONCRETE COLUMNS RETROFITTED WITH FIBER COMPOSITE STRAPS UNDER CYCLIC LOADING

An experimental investigation was conducted to study the seismic behavior of reinforced concrete columns strengthened with fiber composite straps. Ten concrete column-footing assemblages were constructed with a 1/5 dimensional scale factor. The unidirectional composite straps were impregnated with epoxy resin and wrapped around the potential plastic hinge zone of the columns. All specimens were tested under inelastic reversal loading while simultaneously subjected to a constant axial load. Test results show that the seismic resistance of retrofitted concrete columns improves significantly as a result of the confining action of the composite straps. The straps are highly effective in confining the core concrete and preventing the longitudinal reinforcement bars from buckling during an earthquake.