Determination of Moment Parameters of Rectangular Stress Block for High-Strength Prestressed Concrete

Document Type : Original Article

Author

Department of Civil Engineering, Islamic Azad University, Nour Branch, Nour, Iran

Abstract

Various structural design codes for reinforced and prestressed concrete propose different equations and recommendations for the parameters of the rectangular stress block. However, these formulations are often valid only for a specific ultimate strain and are primarily based on concrete with a compressive strength below 50 MPa. In this study, with the aim of evaluating the accuracy and adequacy of these parameters for high-strength prestressed concrete, the stress-strain curve and equivalent stress block parameters were calculated throughout the entire loading process. To achieve this, a simplified third-degree polynomial stress-strain relationship was proposed and compared with experimental data for both compressed (high-strength) and non-compressed (normal-strength) concretes. The results demonstrated that the proposed model has acceptable accuracy in predicting the actual behavior of both compressed and non-compressed concretes, and it can be used to derive instantaneous parameters of the stress block. The obtained stress block parameters were compared with code-based relationships and previous studies, revealing that certain code assumptions require modification when applied to high-strength concrete.

Keywords

Main Subjects

References

  1. Gusella, F. Effect of the plastic rotation randomness on the moment redistribution in reinforced concrete structures. Engineering Structures, 2022; 252: 113652. doi:10.1016/j.engstruct.2021.113652.
  2. Nemati, M., Aminian, A., Rahimi, S., Nematzadeh, M., Jafarzadeh-Taleshi, M., Thai, H.-T. Compressive behavior of prestressed SFRCFST stub columns after heating: Effect of fresh concrete compression technique. Case Studies in Construction Materials, 2025; 23: e04968. doi:10.1016/j.cscm.2025.e04968.
  3. Nazari, A., Toufigh, V. Effects of elevated temperatures and re-curing on concrete containing rice husk ash. Construction and Building Materials, 2024; 439: 137277. doi:10.1016/j.conbuildmat.2024.137277.
  4. Razavi, M., Rahimi, M., Hasanpoor Tichi, A., Nematzadeh, M. Synergistic effects of recycled nylon granules and bacterial nano-cellulose in lightweight concrete: Experiments and predictions. Construction and Building Materials, 2025; 493: 143124. doi:10.1016/j.conbuildmat.2025.143124.
  5. Tarkhan, M., Hosseini-Poul, S.-A., Nematzadeh, M., Shokrollah-Hefzabad, A. Evaluation of post-heating flexural behavior of concrete incorporating ceramic waste and electric arc furnace slag: Experimental and predictive study, and carbon footprint assessment. Construction and Building Materials, 2025; 494: 143207. doi:10.1016/j.conbuildmat.2025.143207.
  6. Nematzadeh, M., Nazari, A., Tayebi, M. Post-fire impact behavior and durability of steel fiber-reinforced concrete containing blended cement–zeolite and recycled nylon granules as partial aggregate replacement. Archives of Civil and Mechanical Engineering, 2021; 22: 5. doi:10.1007/s43452-021-00324-1.
  7. Whitney, C. S. Design of reinforced concrete members under flexure or combined flexure and direct compression. ACI Journal Proceedings, 1937; 33: 483-498. doi:10.14359/8429.
  8. American Concrete Institute (ACI). ACI 318-25: Building Code for Structural Concrete—Code Requirements and Commentary. Farmington Hills (MI): ACI; 2025.
  9. Mattock, A. H., Kriz, L. B., Hognestad, E. Rectangular concrete stress distribution in ultimate strength design. ACI Journal Proceedings, 1961; 57: 875-928. doi:10.14359/8051.
  10. Li, B. Strength and Ductility of Reinforced Concrete Members and Frames Constructed Using High Strength Concrete(PhD Thesis). Christchurch (NZ): University of Canterbury; 1993.
  11. Oztekin, E., Pul, S., Husem, M. Determination of rectangular stress block parameters for high performance concrete. Engineering Structures, 2003; 25: 371-376. doi:10.1016/S0141-0296(02)00172-4.
  12. Ozbakkaloglu, T., Saatcioglu, M. Rectangular stress block for high-strength concrete. ACI Structural Journal, 2004; 101: 475-483. doi:10.14359/13333.
  13. Mertol, H. C., Rizkalla, S., Zia, P., Mirmiran, A. Flexural Design using High-Strength Concrete up to 20 KSI. In: HPC: Build Fast, Build to Last. The 2006 Concrete Bridge Conference; 2006 May 7-10; Nevada, United States. p. 1-18.
  14. Ho, J., Peng, J. Strain gradient effects on flexural strength design of normal-strength concrete columns. Engineering Structures, 2011; 33: 18-31. doi:10.1016/j.engstruct.2010.09.014.
  15. Van Zijl, G., Mbewe, P. Flexural modelling of steel fibre-reinforced concrete beams with and without steel bars. Engineering Structures, 2013; 53: 52-62. doi:10.1016/j.engstruct.2013.03.036.
  16. Prachasaree, W., Limkatanyu, S., Hawa, A., Samakrattakit, A. Development of equivalent stress block parameters for fly-ash-based geopolymer concrete. Arabian journal for science and engineering, 2014; 39: 8549-8558. doi:10.1007/s13369-014-1447-2.
  17. Maruyama, I., Sasano, H. Strain and crack distribution in concrete during drying. Materials and Structures, 2014; 47: 517-532. doi:10.1617/s11527-013-0076-7.
  18. Nematzadeh, M., Naghipour, M. Compressive strength and modulus of elasticity of freshly compressed concrete. Construction and Building Materials, 2012; 34: 476-485. doi:10.1016/j.conbuildmat.2012.02.055.
  19. British Standards Institution. EN 1992-1-2: Eurocode 2: Design of concrete structures. Ispra (IT): EN; 2004.
  20. Canadian Standards Association (CSA). CSA A23.3:19: Design of Concrete Structures. Longueuil (QC): CSA; 2019.
  21. New Zealand Standards Association. NZS 3101.1: Concrete structures standard - The design of concrete structures. Wellington (NZ): NZS; 2006.
  22. Attard, M. M., Stewart, M. G. A two parameter stress block for high-strength concrete. ACI Structural Journal, 1998; 95: 305-317. doi:10.14359/548.
  23. Ibrahim, H. H. H., MacGregor, J. G. Modification of the ACI rectangular stress block for high-strength concrete. ACI Structural Journal, 1997; 94: 40-48. doi:10.14359/459.
  24. Li, B., Park, R., Tanaka, H. Effect of confinement on the behaviour of high strength concrete columns under seismic loading. In: Proceedings, Pacific conference on earthquake engineering; 1991 Nov 20-23; Auckland, New Zealand. p. 67-78.
  25. Azizinamini, A., Baum Kuska, S. S., Brungardt, P., Hatfield, E. Seismic behavior of square high-strength concrete columns. ACI Structural Journal, 1994; 91: 336-345. doi:10.14359/4362.
Civil Engineering and Applied Solutions
Volume 2, Issue 1
January 2026
Pages 22-32

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History

  • Receive Date: 28 August 2025
  • Revise Date: 30 September 2025
  • Accept Date: 04 October 2025
  • First Publish Date: 06 October 2025

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