Title:
Anchorage Zones Reinforced with Discrete Reinforcing Bars and Continuous Meshes
Author(s):
Yail J. Kim and Thi Ha
Publication:
Structural Journal
Volume:
123
Issue:
3
Appears on pages(s):
149-164
Keywords:
anchorage; concentric loading; cracking; end zones; failure; glass fiber-reinforced polymer (GFRP); reinforcing schemes
DOI:
10.14359/51749305
Date:
5/1/2026
Abstract:
This paper presents the behavior of anchorage zones, also known as end zones, with discrete reinforcing bars and continuous meshes. To examine the implications of various reinforcing schemes on the capacity, cracking, and failure of end zones, 50 block specimens are loaded and their responses are analyzed. Test parameters include the types of reinforcing bar materials (steel and glass fiber-reinforced polymer [GFRP]), and the configurations of the reinforcing bars and steel meshes (single and multiple placements). In terms of load-carrying capacity, the specimens embedded with the GFRP reinforcing bars outperform those with the steel reinforcing bars and meshes by 14.0%. The post-peak load drop of the blocks with steel and GFRP reinforcing bars is analogous, due to distributed axial stresses in the unreinforced concrete region, unlike the abrupt drop observed in the specimens with steel meshes that intersect the concrete in orthogonal directions. While concrete splitting originates from local tension generated near the axial compression, the location of cracking is dominated by the path of stress trajectories related to the number of reinforcing bars, which is not recognized in the case of the mesh specimens. The pattern of the isostatic lines of compression clarifies the development of bursting forces that cause cracking in the concrete. A two-stage analytical model is formulated to predict the magnitude of bursting forces and figure out the effects of several parameters on the response of the end zones. The applicability of existing design expressions is assessed and the need for follow-up research is delineated.
Related References:
1. Steensels, R.; Vandoren, B.; Vandewalle, L.; and Degee, H., “Evaluation of End-Zone Detailing of Pre-Tensioned Concrete Girders,” Engineering Structures, V. 187, 2019, pp. 372-383. doi: 10.1016/j.engstruct.2019.02.068
2. Hiremath, G.; Itani, R.; and Vasishth, U., “Test of Continuous Prestressed Concrete Girders Without End Blocks,” Transportation Research Record: Journal of the Transportation Research Board, No. 1223, 1989, pp. 73-83.
3. AASHTO, “AASHTO LRFD Bridge Design Specifications,” ninth edition, American Association of State Highway and Transportation Officials, Washington, DC, 2020.
4. Burdet, O., “Analysis and Design of Anchorage Zones for Posttensioned Concrete Bridges,” PhD dissertation, The University of Texas at Austin, Austin, TX, 1990.
5. Breen, J. E.; Burdet, O.; Roberts, C.; Sanders, D.; and Wollmann, G., “Anchorage Zone Reinforcement for Post-Tensioned Concrete Girders, NCHRP Report 356, Transportation Research Board, Washington, DC, 1994.
6. Srinivasan, S. S.; Rung, M.; and Ferron, R. D., “Factors Affecting Loss in Durability in Prestressed-Concrete Girders with Microcracking,” Journal of Bridge Engineering, ASCE, V. 25, No. 9, 2020, p. 04020068. doi: 10.1061/(ASCE)BE.1943-5592.0001590
7. Okumus, P., and Oliva, M. G., “Evaluation of Crack Control Methods for End Zone Cracking in Prestressed Concrete Bridge Girders,” PCI Journal, V. 58, No. 2, 2013, pp. 91-105. doi: 10.15554/pcij.03012013.91.105
8. Tuan, C. Y.; Yehia, S. A.; Jongpitaksseel, N.; and Tadros, M. K., “End Zone Reinforcement for Pretensioned Concrete Girders,” PCI Journal, V. 49, No. 3, 2004, pp. 68-82. doi: 10.15554/pcij.05012004.68.82
9. Yao, G.; Xiong, X.; and Ge, Y., “Cracking Behavior of Full-Scale Pre-Tensioned Prestressed Concrete Double-Tee Members with Steel-Wire Meshes,” Journal of Building Engineering, V. 44, 2021, p. 102658. doi: 10.1016/j.jobe.2021.102658
10. Sanders, D. H., and Breen, J. E., “Post-Tensioned Anchorage Zones with Single Straight Concentric Anchorages,” ACI Structural Journal, V. 94, No. 2, Mar.-Apr. 1997, pp. 146-158.
11. He, Z.-Q., and Liu, Z., “Investigation of Bursting Forces in Anchorage Zones: Compression-Dispersion Models and Unified Design Equation,” Journal of Bridge Engineering, ASCE, V. 16, No. 6, 2011, pp. 820-827. doi: 10.1061/(ASCE)BE.1943-5592.0000187
12. Zhou, L.; Liu, Z.; and He, Z., “Elastic-To-Plastic Strut-and-Tie Model for Concentric Anchorage Zones,” Journal of Bridge Engineering, ASCE, V. 22, No. 10, 2017, p. 04017070. doi: 10.1061/(ASCE)BE.1943-5592.0001060
13. Hou, D.-W.; Zhao, J.-L.; Shen, S.-L.; and Chen, J., “Investigation and Improvement of Strut-and-Tie Model for Design of End Anchorage Zone in Post-Tensioned Concrete Structure,” Construction and Building Materials, V. 136, 2017, pp. 482-494. doi: 10.1016/j.conbuildmat.2017.01.033
14. Cui, M.; Nie, X.; Fan, J.; Li, S.; Liufu, J.; and Huang, Z., “Experimental Study on the Shear Performance of RC Beams Reinforced with Welded Reinforcement Grids,” Construction and Building Materials, V. 203, 2019, pp. 377-391. doi: 10.1016/j.conbuildmat.2019.01.064
15. Geng, X.; Zhou, W.; and Yan, J., “Reinforcement of Orthogonal Ties in Steel-Fiber-Reinforced Reactive Powder Concrete Anchorage Zone,” Advances in Structural Engineering, V. 22, No. 10, 2019, pp. 2311-2321. doi: 10.1177/1369433219838085
16. ASTM C39/C39M-21, “Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens, ASTM International, West Conshohocken, PA, 2021, 8 pp.
17. ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary (ACI 318R-19) (Reapproved 2022),” American Concrete Institute, Farmington Hills, MI, 2019, 624 pp.
18. Drar, A. A. M., and Matsumoto, T., “Fatigue Analysis of RC Slabs Reinforced with Plain Bars Based on the Bridging Stress Degradation Concept,” Journal of Advanced Concrete Technology, V. 14, No. 1, 2016, pp. 21-34. doi: 10.3151/jact.14.21
19. Chiriatti, L.; Mercado-Mendoza, H.; Apedo, K. L.; Fond, C.; and Feugeas, F., “A Study of Bond Between Steel Rebar and Concrete Under a Friction-Based Approach,” Cement and Concrete Research, V. 120, 2019, pp. 132-141. doi: 10.1016/j.cemconres.2019.03.019
20. Mukhtar, F., and Deifalla, A., “Shear Strength of FRP Reinforced Deep Concrete Beams Without Stirrups: Test Database and a Critical Shear Crack-Based Model,” Composite Structures, V. 307, 2023, p. 116636. doi: 10.1016/j.compstruct.2022.116636
21. Joint ACI-ASCE Committee 445, “Strut-and-Tie Method Guidelines for ACI 318-19—Guide (ACI PRC-445.2-21),” American Concrete Institute, Farmington Hills, MI, 2021, 88 pp.
22. Ugural, A. C., and Fenster, S. K., Advanced Strength and Applied Elasticity, third edition, Prentice-Hall, Hoboken, NJ, 1995.
23. Sahoo, D. K.; Singh, B.; and Bhargava, P., “Investigation of Dispersion of Compression in Bottle-Shaped Struts,” ACI Structural Journal, V. 106, No. 2, Mar.-Apr. 2009, pp. 178-186.
24. Guyon, Y., Prestressed Concrete, Contractors Record, London, UK, 1955.
25. Oluokun, F. A., “Prediction of Concrete Tensile Strength From Its Compressive Strength,” ACI Materials Journal, V. 88, No. 3, May-June 1991, pp. 302-309.
26. Esmaeili, Y.; Eslami, A.; Newhook, J.; and Benmokrane, B., “Performance of GFRP-Reinforced Concrete Beams Subjected to High-Sustained Load and Natural Aging for 10 Years,” Journal of Composites for Construction, ASCE, V. 24, No. 5, 2020, p. 04020054. doi: 10.1061/(ASCE)CC.1943-5614.0001065
27. Sawpan, M. A., “Effects of Alkaline Conditioning and Temperature on the Properties of Glass Fiber Polymer Composite Rebar,” Polymer Composites, V. 37, No. 11, 2016, pp. 3181-3190. doi: 10.1002/pc.23516
28. El-Metwally, S., and Chen, W. F., Structural Concrete: Strut-and-Tie Models for Unified Design, CRC Press, Boca Raton, FL, 2017.
29. ACI Committee 440, “Building Code Requirements for Structural Concrete Reinforced with Glass Fiber-Reinforced Polymer (GFRP) Bars —Code and Commentary (ACI CODE-440.11-22),” American Concrete Institute, Farmington Hills, MI, 2023, 266 pp.
30. Nawy, E. G., Prestressed Concrete: A Fundamental Approach, fifth edition, Prentice Hall, Upper Saddle River, NJ, 2009.