Title: Behavior of unbonded multistrand posttensioning anchorage systems under monotonic and cyclical loads
Date Published: January-February 2017
Page Numbers: 31-48
Authors: Daniel A. Abramson, Eric S. Musselman, and Sri Sritharan
Click here to view the full journal article
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.
ACI (American Concrete Institute) Committee 423. 2014. Specification for Unbonded Single-Strand Tendon Materials. ACI 423.7-14. Farmington Hills, MI: ACI.
ACI Committee 423. 2005. Recommendations for Concrete Members Prestressed with Unbonded Tendons. ACI 423.3-05. Farmington Hills, MI: ACI.
PTI (Post-Tensioning Institute). 2000. Specification for Unbonded Single Strand Tendons. PTI M10.2-00. Phoenix, AZ: PTI.
ACI Committee 318. 2014. Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14). Farmington Hills, MI: ACI.
Walsh, K. Q., and Y. C. Kurama. 2010. “Behavior of Unbonded Post-tensioning Monostrand Anchorage Systems under Monotonic Tensile Loading.” PCI Journal 55 (1): 97–117.
Walsh, K. Q., and Y. C. Kurama. 2012. “Effects of Loading Conditions on the Behavior of Unbonded Post-tensioning Strand-Anchorage Systems.” PCI Journal 57 (1): 76–96.
Walsh, K. Q., R. L. Draginis, R. M. Estes, and Y. C. Kurama. 2013. “Effects of Anchor Wedge Dimensional Parameters on Post-Tensioning Strand Performance.” Structural Engineering Research Report NDSE-2013-02. Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame.
Musselman, E. S., M. Fournier, P. McAlpine, and S. Sritharan. 2015. “Behavior of Unbonded Post tensioning Monostrand Anchorage Systems under Short Duration, High Amplitude Cyclical Loading.” Engineering Structures 104: 116–125.
PTI (Post-Tensioning Institute). 1998. Acceptance Standards for Post-tensioning Systems. PTI M50.1-98. Farmington Hills, MI: PTI.
Hayes, N. O., and R. Draginis. 2010. Anchor wedge configuration for tendon anchors. US Patent 7,726,082 B2, filed December 4, 2004, and issued June 1, 2010.
Corven, J., and A. Moreton. 2013. “Appendix A–Terminology.” In Post-Tensioning Tendon Installation and Grouting Manual. Version 2.0. FHWA-NHI-13-026. Washington, DC: U.S. Department of Transportation, Federal Highway Administration.
Nakaki, S. D., J. F. Stanton, and S. Sritharan. 1999. “An Overview of the PRESSS Five-Story Precast Test Building.” PCI Journal 44 (2): 26–39.
Priestley, M. J. N., S. Sritharan, J. R. Conley, and S. Pampanin. 1999. “Preliminary Results and Conclusions from the PRESSS Five-Story Precast Concrete Test Building.” PCI Journal 44 (6): 42–67.
Sritharan, S. 2002. “Performance of Four Jointed Precast Frame Systems under Simulated Seismic Loading.” In Proceedings of the Seventh National Conference on Earthquake Engineering, July 21-25, 2002, Boston, Mass. Oakland, CA: Earthquake Engineering Research Institute.
Sritharan, S., S. Aaleti, R. S. Henry, K.-Y. Liu, and K.-C. Tsai. 2015. “Precast Concrete Wall with End Columns (PreWEC) for Earthquake Resistant Design.” Earthquake Engineering and Structural Dynamics 44 (12): 2075–2092. doi: 10.1002/eqe.2576.
ACI Innovation Task Group 5. 2008. Acceptance Criteria for Special Unbonded Post-tensioned Precast Structural Walls Based on Validation Testing. ACI ITG-5.1-07. Farmington Hills, MI: ACI.
ASTM Subcommittee A01.05. 2016. Standard Specification for Low-Relaxation, Seven-Wire Steel Strand for Prestressed Concrete. ASTM A416/A416M-16. West Conshohocken, PA: ASTM International.
ASTM Subcommittee A04.02. 2014. Standard Specification for Ductile Iron Castings. ASTM A536-84. West Conshohocken, PA: ASTM International.
Hayes, N. O., and R. Draginis. 2010. Anchor system with substantially longitudinally equal wedge compression. US Patent 7,765,752 B2, filed February 20, 2008, and issued August 3, 2010.
International Code Council Evaluation Service (ICC-ES). 2007. Acceptance Criteria for Post-Tensioned Anchorages and Couplers of Prestressed Concrete. Evaluation Report AC303. Whittier, CA: ICC-ES.
Yates, D. L. 1988. “A Study of Fretting Fatigue in Post-Tensioned Concrete Beams.” MS thesis. University of Texas at Austin.
Acosta, J. A. A. 1991. “Instrumentation Systems for Post-Tensioned Segmental Box Girder Bridges.” MS thesis. University of Texas at Austin.
Nazari, M., S. Sritharan, and S. Aaleti. 2014. “An Experimental Evaluation of Unbonded Post-tensioned Precast Rocking Walls.” In Proceedings of the 60th PCI Convention and National Bridge Conference, September 6–9, 2014, National Harbor, Md. Chicago, IL: PCI. CD-ROM.