Flexural capacity of fiber-reinforced polymer strengthened unbonded post-tensioned members

Abstract

Experimental and analytical investigations were carried out for evaluating the nominal moment capacity of unbonded posttensioned members when strengthened using external fiberreinforced polymer (FRP) composites. In the experimental part of the study, 36 simply supported specimens were tested to failure. The main test parameters included area of internal tension reinforcement, area of external FRP reinforcement, span-depth ratio of the member, profile of the prestressing tendons, and type of concrete structural system. In the analytical part of the study, a designoriented procedure for evaluating the nominal moment capacity of FRP-strengthened post-tensioned members with internal or external unbonded tendon systems is developed. The procedure is consistent with the approach proposed in ACI Committee 440 report for reinforced concrete or bonded prestressed concrete members, and is applicable for both simply supported and continuous members. The accuracy of the design approach was verified by comparing it with the test results of the experimental part of this investigation. Copyright © 2014, American Concrete Institute.