This paper is on the behavior and design of anchorages for unbonded post-tensioning (PT)strands in seismic regions. While current design guidelines for unbonded post-tensionedstructures require that the strands remain essentially linear-elastic under the "Design BasisEarthquake," significant post-yield strand stresses can develop under the "Maximum ConsideredEarthquake." Thus, the use of unbonded post-tensioning for seismic resistance can put theanchorage regions under extreme demands where premature strand wire fractures can occur. Thispaper describes an experimental study on the behavior of single strand/anchorage systems undermonotonic tension loading, considering various design and construction parameters that canaffect the performance of a strand inside an anchor. The parameters investigated include: (1)strand size (0.5-inch and 0.6-inch nominal strand diameters); (2) anchor type (cast type andbarrel type anchors); (3) number of anchor wedges (2-piece and 3-piece wedges); and (4)presence of a binding ring around the wedges. The test results are used to evaluate strand/anchorconfigurations that may provide better probability of reaching higher strand ductility.
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