Strengthening Effect of Reinforced Concrete Elements with Polyacetal Fiber Sheets

This paper describes the strengthening effect of RC elements with newly developed polyacetal-fiber (PAF) sheets. Typical properties of the polyacetal fiber obtained by drawing polyoxymethylene as a material for strengthening, are high strength, high strain capacity, high resistance to shear force, light weight and easy to handle by preformability. Polyacetal fiber reinforced special epoxy-resin that is optimized for this fiber, offers an outstanding combination of properties not available from steel and other high strength fibers, such as glass, aramid and carbon fibers which are used for the seismic retrofit of concrete structures. The advantages realized were the overall cost savings and strengthening of RC elements in one day, conditionally. Tests conducted to investigate the strengthening effect of concrete elements with polyacetal FRP are introduced in this paper. The loading tests were performed on 14 RC columns. The objective of the lateral loading tests is to investigate the shear and ductility strengthening effect with polyacetal FRP, and to clarify the possibility of this FRP as a material for seismic retrofit. The research work shows the prominent validity of concrete elements post-strengthened with polyacetal fiber for shear strength and ductility.