Flexural behavior of full-scale, carbon-fiber-reinforced polymer prestressed concrete beams

Abstract

Highway bridge beams are subjected to aggressive environments, temperature fluctuations, and millions of loading cycles throughout their service life. The combi­nation of these effects can result in the reduction of the service life of structural components. In the past decades, more-durable composite materials, such as carbon-fiber-reinforced polymers (CFRPs) have been implemented in concrete structures to address problems related to environmental durability. To date, prestress­ing applications of CFRP in beams have been mostly investigated for rectangular cross sections, which are not representative of the geometry used in modern highway bridges. In addition, the construction and detailing aspects of CFRP prestressed concrete beams have not been investigated outside of laboratory conditions. This paper describes an experimental investigation conducted on eight 40 ft (12 m) long AASHTO Type I prestressed concrete beams with 3 ft (0.9 m) wide composite con­crete decks and detailed identically to highway bridge beams in practice. Three beams were pretensioned with carbon-fiber-composite cables, four beams with CFRP bars, and one with prestressing steel. The beams were tested under monotonic and fatigue loading. All CFRP prestressed concrete beams were designed to fail due to the rupture of the prestressing CFRP. The CFRP prestressed concrete beams exhibit several desirable features of the typical steel prestressed concrete beams in terms of serviceability and strength.