Title:
Conventional and High-Strength Hooked Bars—Part 2: Data Analysis
Author(s):
J. Sperry, D. Darwin, M. O’Reilly, R. D. Lequesne, S. Yasso, A. Matamoros, L. R. Feldman, and A. Lepage
Publication:
Structural Journal
Volume:
114
Issue:
1
Appears on pages(s):
267-276
Keywords:
anchorage; beam-column joints; bond and development; highstrength concrete; high-strength steel; hooks; reinforcement
DOI:
10.14359/51689457
Date:
1/1/2017
Abstract:
Empirical equations are developed to characterize the anchorage strength of hooked bars. The equations are based on tests of 245 simulated beam-column joint specimens with two hooked bars: 146 with confining reinforcement and 99 without. Bar stresses at failure for specimens used in the analysis ranged from 30,800 to 144,100 psi (212 to 994 MPa), and concrete compressive strengths ranged from 2570 to 16,200 psi (17.7 to 112 MPa). For the specimens analyzed, hooked bar anchorage strength was proportional to concrete compressive strength raised to the 0.29 power. For confining reinforcement parallel to and located within eight or 10 bar diameters of the straight portion of the hooked bar, the contribution to anchorage strength was proportional to the area of confining reinforcement; for confining reinforcement perpendicular to the straight portion of the bar, more legs of the confining reinforcement contributed to anchor strength, but each leg made a smaller contribution.
Related References:
Abrams, D. A., 1913, “Tests of Bond between Concrete and Steel,” Bulletin No. 71, Engineering Experiment Station, University of Illinois, Urbana, IL, 238 pp.
ACI Committee 318, 2011, “Building Code Requirements for Structural Concrete (ACI 318-11) and Commentary (ACI 318R-11),” American Concrete Institute, Farmington Hills, MI, 503 pp.
ACI Committee 318, 2014, “Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14),” American Concrete Institute, Farmington Hills, MI, 519 pp.
ACI Committee 408, 2003, “Bond and Development of Straight Reinforcing Bars in Tension (ACI 408R-03),” American Concrete Institute, Farmington Hills, MI, 49 pp.
Ahmad, S. H., and Shah, S. P., 1985, “Structural Properties of High Strength Concrete and Its Implications for Precast Prestressed Concrete,” PCI Journal, V. 30, No. 6, Nov.-Dec., pp. 92-119
Azizinamini, A.; Stark, M.; Roller, J. J.; and Ghosh, S. K., 1993, “Bond Performance of Reinforcing Bars Embedded in High-Strength Concrete,” ACI Structural Journal, V. 90, No. 5, Sept.-Oct., pp. 554-561.
Darwin, D.; Barham, S.; Kozul, R.; and Luan, S., 2001, “Fracture Energy of High-Strength Concrete,” ACI Materials Journal, V. 98, No. 5, Sept.-Oct., pp. 410-417.
Darwin, D., and Graham, E. K., 1993, “Effect of Deformation Height and Spacing on Bond Strength of Reinforcing Bars,” ACI Structural Journal, V. 90, No. 6, Nov.-Dec., pp. 646-657.
Darwin, D.; Lutz, L. A.; and Zuo, J., 2005, “Recommended Provisions and Commentary on Development and Lap Splice Lengths for Deformed Reinforcing Bars in Tension,” ACI Structural Journal, V. 102, No. 6, Nov.-Dec., pp. 892-900.
Darwin, D.; Zuo, J.; Tholen, M. L.; and Idun, E. K., 1996, “Development Length Criteria for Conventional and High Relative Rib Area Reinforcing Bars,” ACI Structural Journal, V. 93, No. 3, May-June, pp. 347-359.
Draper, N. R., and Smith, H., 1981, Applied Regression Analysis, second edition, Wiley, New York, 709 pp.
Hamad, B. S.; Jirsa, J. O.; and D’Abreu de Paulo, N. I., 1993, “Effect of Epoxy Coating on Bond Anchorage of Reinforcing in Concrete Structures,” ACI Structural Journal, V. 90, No. 1, Jan.-Feb., pp. 77-88.
Lee, J., and Park, H., 2010, “Bending—Applicability Study of Ultra-Bar (SD 600) and Ultra-Bar for Rebar Stirrups and Ties (SD 500 and 600) for Compression Rebar,” KCI-R-10-006 Report, Korea Concrete Institute, Seoul, Korea, Aug., 504 pp. (in Korean)
Lutz, L. A., and Gergely, P., 1967, “Mechanics of Bond and Slip of Deformed Bars in Concrete,” ACI Journal Proceedings, V. 64, No. 11, Nov., pp. 711-721.
Marques, J. L., and Jirsa, J. O., 1975, “A Study of Hooked Bar Anchorages in Beam-Column Joints,” ACI Journal Proceedings, V. 72, No. 5, May-June, pp. 198-209.
Pinc, R.; Watkins, M.; and Jirsa, J. O., 1977, “The Strength of the Hooked Bar Anchorages in Beam-Column Joints,” CESRL Report No. 77-3, Department of Civil Engineering-Structures Research Laboratory, University of Texas at Austin, Austin, TX, 67 pp.
Ramirez, J. A., and Russell, B. W., 2008, “Transfer, Development, and Splice Length for Strand/Reinforcement in High-Strength Concrete,” NCHRP Report 603, National Cooperative Highway Research Program, Transportation Research Board, Washington, DC, 122 pp.
Seliem, H. M.; Hosny, A.; Rizkalla, S.; Zia, P.; Briggs, M.; Miller, S.; Darwin, D.; Browning, J.; Glass, G. M.; Hoyt, K.; Donnelly, K.; and Jirsa, J. O., 2009, “Bond Characteristics of ASTM A1035 Steel Reinforcing Bars,” ACI Structural Journal, V. 106, No. 4, July-Aug., pp. 530-539.
Sperry, J.; Al-Yasso, S.; Searle, N.; DeRubeis, M.; Darwin, D.; O’Reilly, M.; Matamoros, A.; Feldman, L.; Lepage, A.; Lequesne, R.; and Ajaam, A., 2015a, “Anchorage of High-Strength Reinforcing Bars with Standard Hooks,” SM Report No. 111, University of Kansas Center for Research, Lawrence, KS, June, 243 pp.
Sperry, J.; Darwin, D.; O’Reilly, M.; and Lequesne, R., 2015b, “Anchorage Strength of Conventional and High-Strength Hooked Bars in Concrete,” SM Report No. 115, University of Kansas Center for Research, Lawrence, KS, Dec., 266 pp.
Sperry, J.; Yasso, S.; Searle, N.; DeRubeis, M.; Darwin, D.; O’Reilly, M.; Matamoros, A.; Feldman, L. R.; Lepage, A.; Lequesne, R.; and Ajaam, A., 2017, “Conventional and High-Strength Hooked Bars—Part 1: Anchorage Tests,” ACI Structural Journal, V. 114, No. 1, Jan.-Feb., pp. 251-262
Zuo, J., and Darwin, D., 2000, “Splice Strength of Conventional and High Relative Rib Area Bars in Normal and High-Strength Concrete,” ACI Structural Journal, V. 97, No. 4, July-Aug., pp. 630-641.