Effect of Tow Sheet Composite Wrap Architecture on Strengthening of Concrete Due to Confinement: I—Experimental Studies

Worldwide there is a need for the renewal of infrastructure because of age, deterioration, misuse, lack of timely repair and maintenance, use of improper materials and/or techniques in the original construction, and even changing needs. Notwithstanding the need for retrofit and repair methods for column-type structural elements, there is also a need for new techniques that would increase the confining action of concrete, as well as enhance the load-carrying capacity and ductility of such structures from a strengthening, rather than a seismic, viewpoint. This study investigates the use of carbon-fiber-reinforced jackets applied to concrete stub columns through the use of tow-sheet-type fabric forms. The primary emphasis is on the investigation of orientation and thickness effects of the composite wraps on the load-carrying efficiency and enhanced ductility of the new structural elements. It was seen that the predominant use of hoop reinforcement provides significant enhancement in concrete strength through confining action and also offers the potential for fabrication of concrete shell-type elements that would enable reinforcing action without the use of steel and the attending problems of corrosion.