Experimental study of influence of bond on flexural behavior of concrete beams pretensioned with aramid fiber reinforced plastics

An experimental program was formulated to investigate the flexural behavior of concrete prestressed with aramid fiber reinforced plastic (AFRP) tendon s. The particular focus was the influence of the bond between an AFRP tendo n and concrete on the flexural response of a beam. In the main test series, pretensioned concrete beams were cast using either one of two types of AFRP tendons or steel tendons. The influence of bond w as studied by testing beams with fully-bonded tendons, unbonded tendons, or partially-bonded tendons. It was found that although the fully-bonded beam s had a high ultimate load capacity, only limited rotation occurred prior t o failure. In contrast, large rotations were noted in the unbonded beams, b ut the strengths of these members were significantly (25 percent) lower tha n those of the Sully-bonded beams. The only beams that achieved both a high rotation capacity and a high ultimate load capacity were the beams with pa rtially-bonded tendons. It is suggested that the use of partially-bonded tendons could provide the basis of a new design method for concrete beams prestressed with fiber rein forced plastic (FRP) tendons.