ABSTRACT
Abstract The damage sustained by bridge columns during the recent earthquakes worldwide clearly attests to the need for effective and economical techniques for retrofitting of these structural elements. The lack of adequate lateral reinforcement has been recognized as a major cause of failure of these columns. An effective technique to enhance the strength and ductility of seismically deficient concrete columns is to provide external reinforcement in the form of a confining shell around the column. Composite materials, due to their high strength and versatility, provide excellent candidate materials for this application. This paper discusses the utilization of resinimpregnated composite straps for strengthening substandard concrete columns. Ten circular and rectangular column specimens were wrapped with composite straps and tested under reversed inelastic cyclic loading. Hysteresis loops of retrofitted columns were compared with those for unretrofitted, control specimens to quantify the gain in strength and ductility. Analytical models were developed to predict the structural enhancements resulting from the concrete confinement. These models were used in a parametric study to determine the effect of different design variables on the overall structural performance of the retrofitted columns. The analytical and experimental results indicate the great potential of this technique for field application. Keywords: Earthquake, fiber composites, column, concrete, confinement, seismic, strengthening, wrapping.
