Lateral Confinement of Concrete Using FRP Reinforcement


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Title: Lateral Confinement of Concrete Using FRP Reinforcement

Author(s): A. Nanni, M.S. Norris, and N.M. Bradford

Publication: Special Publication

Volume: 138


Appears on pages(s): 193-210

Keywords: Bend tests; compression tests; concretes; fiber reinforced plastics; fibers; glass fibers; lateral confinement; loading tests; reinforcing materials; repairs; strengthening; wrapping1

Date: 9/1/1993

Lateral confinement of concrete members by means of spirally wrapping fiber-reinforced-plastic (FRP) composites onto the concrete surface may increase compressive strength and ultimate strain (pseudo-ductility). It may also provide a mechanism for shear resistance, and inhibit longitudinal steel reinforcement buckling. Lateral confinement of concrete members as a strengthening/repair technology is expected to have an impact in the rehabilitation/renovation of buildings and infrastructure. Structures that have been damaged, or need to comply with new code requirements, or are subjected to more severe usage are the primary targets. In this project, an experimental and analytical study of concrete strengthened with FRP lateral confinement I conducted using compression cylinders (300 and 600 mm in length) and l/4 scale column-type specimens. The latter specimens have a circular cross section and given longitudinal/transverse steel reinforcement characteristics. Column-type specimens are subjected to cyclic flexure with and without axial compression. When an aramid FRP tape is used as the lateral reinforcement, the variables are tape area and spiral pitch. In the case of filament winding with glass fiber, the thickness of the FRP shell is varied. The limited experimental results obtained at this stage of the research program indicate that lateral confinement significantly increases compressive strength and pseudoductility under uniaxial compression.