Secondary Anchorage In Post-Tensioned Bridge Systems

Post-tensioning (PT) tendons in segmental bridges are often anchored within the deviator and pier segments. The effectiveness of the PT system is therefore dependent on proper anchorage function. However, anchorage failure may occur due to corrosion of the strand at the anchor head and subsequently cause the PT force to transfer within the pier segment or slacking of the tendon to occur. Following tendon stressing, the anchorage assembly and ducts that house the tendon are filled with grout. These short bonded regions could, in the event of anchorage failure, provide secondary anchorage. This paper presents the results of a full-scale experimental investigation on bonded anchorage tendon pullout. The study focuses on the embedment length required to develop the in-service PT force within the pier segment. Seven, twelve, and nineteen 15 mm (0.6 in.) diameter low-relaxation strand tendons with various bonded lengths were considered. Copyright © 2013, American Concrete Institute. All rights reserved