Posttensioned Anchorage Zone Enhancement with Fiber-Reinforced Concrete

The secondary spiral and skin reinforcement in the anchorage zone of prestressed posttensioned girders causes congestion and poses difficulty in the placement of concrete. It is also labor intensive to produce and place secondary anchorage reinforcement. The objective of this study was to determine the feasibility of reducing the secondary reinforcement with steel fibers for posttensioned anchor zones. The AASHTO Special Anchorage Device Acceptance Test was performed in this study. Variations of spiral and skin reinforcement, with concrete strengths ranging from $37.9\mathrm{MPa}$ $\left(\mathrm{5,500}\mathrm{psi}\right)\text{to}52\mathrm{MPa}$ $\left(\mathrm{7,500}\mathrm{psi}\right)$ , were utilized to investigate the performance of the two types of steel fibers with various amounts. The experimental results indicated that 1% hooked-end steel fibers could eliminate all secondary reinforcement for a minimum concrete strength of $40.7\mathrm{MPa}$ $\left(\mathrm{5,900}\mathrm{psi}\right)$ . Lower volumes of steel fibers may also be used to reduce secondary reinforcements.