Bond fatigue tests of beams simulating pretensioned concrete crossties

摘要

style="text-align: left;">One-hundred and eight tests of rectangular beams simulating pretensioned concrete crossties were performed. Repeated loads were applied to one of four selected locations near the end of each beam.  The maximum load was either that required to open a crack of 0.001 in. width or a value of 15 percent greater than the crack opening load. Three strand surface conditions and two methods of prestress  release were used to produce test specimens with a wide range of realistic transfer lengths. Conclusions about the effect of load location on the strand transfer length necessary to obtain a bond fatigue life of three  million cycles are given. Finally, design recommendations  are put forth. >References style="text-align: left;">1. Janney, Jack R., target="_blank" title=""Nature of Bond in Pretensioned Prestressed Beams,"" href=" http://dx.doi.org/10.14359/11790 ">"Nature of Bond in Pretensioned Prestressed Beams," ACI Journal, Proceedings, V. 50, No. 9, May 1954, pp. 717-736. Also PCA Development Department Bulletin D2. style="text-align: left;">2. Hanson, Norman W., and Kaar, Paul H., target="_blank" title=""Flexural Bond Tests of Pretensioned Prestressed Beams,"" href="http://dx.doi.org/10.14359/11389 ">"Flexural Bond Tests of Pretensioned Prestressed Beams," ACI Journal, Proceedings, V. 55, January 1959, pp. 783-802. Also PCA Development Department Bulletin D28. style="text-align: left;">3. Kaar, P. H., La Fraugh, R. W., and Mass, M. A., target="_blank" title=""Influence of Concrete Strength on Strand Transfer Length,"" href="http://dx.doi.org/10.15554/pcij.10011963.47.67 ">"Influence of Concrete Strength on Strand Transfer Length," PCI JOURNAL, V. 8, No. 5, October 1963, pp. 47-67. Also PCA Development Department Bulletin D71. style="text-align: left;">4. Kaar, P. H., and Magura, Donald D., target="_blank" title=""Effect of Strand Blanketing on Performance of Pretensioned Girders,"" href="http://dx.doi.org/10.15554/pcij.12011965.20.34 ">"Effect of Strand Blanketing on Performance of Pretensioned Girders," PCI  JOURNAL, V. 10, No. 6, December1965, pp. 20-34. Also PCA Development Department Bulletin D97. style="text-align: left;">5. Hognestad, E., Hanson, N. W., Kriz,. L. B., and Kurvits, O. A., "Facilitiess and Test Methods of PCA Structural  Laboratory." Papers under various titles in Journal of the PCA Research and Development Laboratories, V. 1, No. 1,, January 1959, pp. 12-20, 40-44; V. 1,.  No. 2, May 1959, pp. 30-37; and V. 1,,No. 3, September 1959, pp. 35-41; reprinted jointly as PCA Development  Department  Bulletin D33. style="text-align: left;">6. Hanson, N. W., Hsu, T. T. C., Kurvits,. O. A., and Mattock, A. H., "Facilities  and Test Methods of PCA Structural Laboratory-Improvements 1960-65."Papers under various titles in Journal:  of the PCA Research and Development  Laboratories, V. 3, No. 2, May 1960,. pp. 27-31; V. 7, No. 1, January 1965,, pp. 2-9; and V. 7, No. 2, May 1965,.  pp. 24-38; reprinted jointly as PCA Development Department Bulletin D91. style="text-align: left;">7. ACI Committee 215, target="_blank" title=""Considerations.for Design of Continuous Structures,  Subjected to Fatigue Loading,"" href=" http://dx.doi.org/10.14359/11172 ">"Considerations.for Design of Continuous Structures,  Subjected to Fatigue Loading," ACI Journal, Proceedings, V. 71, No. 3,, March 1974, pp. 97-121.