Title: Measured Transfer Lengths of 0.5 and 0.6 in. Strands in Pretensioned Concrete
Date: September-October, 1996
Volume: 41
Issue: 5
Page number: 44-65
Author(s): Bruce W. Russell, Ned H. Burns
https://doi.org/10.15554/pcij.09011996.44.65
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Abstract
Transfer lengths were measured for both 0.5 and 0.6 in. (12.7 and 15.2 mm) diameter strands for a wide variety of research variables that included strand spacing, debonding strand, confining reinforcement, number of strands per specimen and size and shape of the cross section. Overall, the test results indicate that the transfer bond characteristics for 0.6 in. (15.2 mm) strands are very similar to the bond behavior for 0.5 in. (12.7 mm) strands. Furthermore, average measured transfer lengths for both sizes of strand are marginally predicted by current AASHTO and ACI Code provisions. These results clearly demonstrate that 0.6 in. (15.2 mm) strands can be safely employed in pretensioned concrete members with spacings of 2 in. (50.8 mm). However, the ranges of measured transfer lengths clearly indicate that a significant proportion of actual measured transfer lengths exceed the current design recommendations of either 50db or f.3sedb/ Therefore, to incorporate a more consistent level of safety, transfer lengths should be approximated by the expression fse db/2.
References
1. ACI Committee 318, “Building Code Requirements for Structural Concrete (ACT 3 18-95),” American Concrete Institute, Farmington Hills, MI, 1995.
2. AASHTO, Standard Specifications for Highway Bridges, 15th Edition, American Association of State Highway and Transportation Officials, Washington, D.C., 1992.
3. Janney, Jack R., “Nature of Bond in Pre-Tensioned Prestressed Concrete,” ACI Journal, V. 50, No. 9, May 1954, pp. 717-736.
4. Hanson, Norman W., and Kaar, Paul H., “Flexural Bond Tests of Pretensioned Prestressed Beams,” ACJ Journal, V. 55, No. 7, January 1959, pp. 783-802.
5. Janney, Jack R., “Report of Stress Transfer Length Studies on 270K Prestressing Strand,” PCI JOURNAL, V. 8, No. 1, February 1963, pp. 41-45.
6. Kaar, Paul H., LaFraugh, Robert W., and Mass, Mark A., “Influence of Concrete Strength on Strand Transfer Length,” PCI JOURNAL, V. 8, No. 5, October 1963, pp. 47-67.
7. Hanson, Norman W., “Influence of Surface Roughness of Prestressing Strand in Bond Performance,” PCI JOURNAL, V. 14, No. 1, February 1969, pp. 32-45.
8. Kaar, Paul H., and Hanson, Norman W., “Bond Fatigue Tests of Beams Simulating Pretensioned Concrete Crossties,” PCI JOURNAL, V. 20, No. 5, September-October 1975, pp. 65-80.
9. Rose, D. R., and Russell, B. W., “In vestigation of Standardized Tests to Measure the Bond Performance of Prestressing Strands,” Research Report (Preliminary), Fears Structural Engineering Laboratory, School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, July 1996, 212 pp.
10. Castrodale, R. W., Kreger, M. E., and Burns, N. H., “A Study of Pretensioned High Strength Concrete Girders in Composite Highway Bridges-Laboratory Tests,” Research Report 381-3, Center for Transportation Research, University of Texas at Austin, Austin, TX, January 1988.
11. Mitchell, D., Cook, W. D., Khan, A. A., and Tham, T., “Influence of High Strength Concrete on Transfer and Development Length of Pretensioning Strand,” PCI JOURNAL, V. 38, No. 3, May-June 1993, pp. 52-66.
12. Russell, B. W., and Burns, N. H., “Design Guidelines for Transfer, Development and Debonding of Large Diameter Seven Wire Strands in Pretensioned Concrete Girders,” Research Report 1210-5F, Center for Transportation Research, University of Texas at Austin, Austin, TX, January 1993.
13. Paulsgrove, G. A., and Russell, B. W., “Development Length Guidelines for Pretensioned Strands,” Research Report, University of Oklahoma, Norman, OK, July 1996, 262 pp.
14. Unay, I. 0., Russell, B. W., Burns, N. H., and Kreger, M. E., “Measurement of Transfer Length on Prestressing Strands in Prestressed Concrete Specimens,” Research Report 1210-1, Center for Transportation Research, University of Texas at Austin, Austin, TX, March 1991.
15. Anderson, Arthur R., and Anderson, Richard G., “An Assurance Criterion for Flexural Bond in Pretensioned Hollow Core Units,” ACI Journal, V. 73, No. 8, August 1976, pp. 457-464.
16. Deatherage, Harold J., and Burdette, Edwin, G., “Development Length and Lateral Spacing Requirements of Prestressing Strand for Prestressed Concrete Bridge Products,” Transportation Center, University of Tennessee, Knoxville, TN, February 1991.
17. Deatherage, Harold J., Burdette, Edwin G., and Chew, Chong Key, “Development Length and Lateral Spacing Requirements of Prestressing Strand for Prestressed Concrete Bridge Girders,” PCI JOURNAL, V. 39, No. 1, January-February 1994, pp. 70-83.
18. Cousins, Thomas E., Johnston, David W., and Zia, Paul, “Bond of Epoxy Coated Prestressing Strand,” Center for Transportation Engineering Studies, Department of Civil Engineering, North Carolina State University, Durham, NC, December 1986.
19. Cousins, Thomas E., Johnston, David W., and Zia, Paul, “Development Length of Epoxy-Coated Prestressing Strand,” ACI Materials Journal, V. 87, No. 4, July-August 1990, pp. 309-3 18.
20. Cousins, T. E., Johnson, D. W., and Zia, Paul, “Transfer and Development Length of Epoxy Coated and Uncoated Prestressing Strand,” PCI JOURNAL, V. 35, No. 4, July-August 1990, pp. 92-103.
21. Shahawy, M., and Batchelor, B. DeV, “Bond and Shear Behavior of Prestressed AASHTO Type II Beams,” Progress Report No. 1, Structural Research Center, Florida Department of Transportation, Tallahassee, FL, February 1991.
22. Shahawy, Mohsen A., Issa, Moussa, and Batchelor, Barrington deV, “Strand Transfer Lengths in Full Scale AASHTO Prestressed Concrete Girders,” PCI JOURNAL, V. 37, No. 3, May-June 1992, pp. 84-96.
23. Buckner, C. Dale, “A Review of Strand Development Length for Pretensioned Concrete Members,” PCI JOURNAL, V. 40, No.2, March-April 1995, pp. 85-105.
24. Brooks, M. D., Gerstle, K. H., and Logan, D. R., “Effect of Initial Strand Slip on the Strength of Hollow-Core Slabs,” PCI JOURNAL, V. 33, No. 1, January-February 1988, pp. 90-111.
25. Russell, B. W., and Burns, N. H., Comments on “A Review of Strand Development Length for Pretensioned Concrete Members” by C. Dale Buckner, PCI JOURNAL, V. 41, No. 2, March-April 1996, pp. 112-127.
26. Englekirk, R. E., and Beres, A., “The Need to Develop Shear Ductility in Prestressed Members,” Concrete International, V. 16, No. 10, October 1994, pp. 49-56.