Title: Behavior of unbonded multistrand posttensioning anchorage systems under monotonic and cyclical loads
Date Published: January-February 2017
Volume: 62
Issue: 1
Page Numbers: 31-48
Authors: Daniel A. Abramson, Eric S. Musselman, and Sri Sritharan

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The growing popularity of unbonded posttensioned structures designed for seismic resiliency, in conjunction with recent research indicating the inability of commercially available posttensioning anchorage systems to meet current industry certification standards, has prompted the need to investigate and better understand posttensioning anchorage systems. Recent research has focused on single-strand posttensioning systems; however, virtually no published literature is available regarding the behavior of multistrand anchorages. This paper presents results from a comprehensive laboratory evaluation of the fracture and ultimate strength and strain capacities of multistrand posttensioning anchorage systems for use in seismic-resilient rocking structures. The testing program encompassed two anchorage manufacturers, two anchorage alignment configurations, and two wedge geometries under both monotonic and cyclic loading. The results show that modifying the wedge geometry can improve the performance of commercially available posttensioning anchorages and that a strain limit of 1% should be used for seismic applications.


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