Review and improvement of stress-strain models for FRP-confined concrete

Raisszadeh, Amirhosein; Ziaadiny, Hadi; Khojastehfar, Ehsan

doi:10.61882/NMCE.2505.1090

Review and improvement of stress-strain models for FRP-confined concrete

Document Type : Research

Authors

Amirhosein Raisszadeh

Hadi Ziaadiny

Ehsan khojastehfar

Assistant Professor, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran

10.61882/NMCE.2505.1090

Abstract

The cyclic stress-strain behavior of FRP-confined concrete columns is a key aspect of their performance, particularly in the context of seismic retrofitting and design. Significant research has been conducted in recent years to study the cyclic response of FRP-confined concrete in both circular and rectangular columns subjected to unloading and reloading cycles. These studies have led to the development of various cyclic stress-strain models to predict the behavior of FRP-confined concrete columns under such loading conditions.
However, critical gaps remain in the modeling of early-stage unloading strains, reloading slope reduction, and cross-section-dependent behavior. This paper begins by introducing the fundamental components of cyclic stress-strain behavior. It then reviews and evaluates the existing models proposed for each aspect of this behavior, focusing on comparing their predictions with experimental data. Furthermore, modifications are suggested for components of the cyclic models that exhibit discrepancies when validated against experimental observations. These include a proposed reloading slope factor and refined unloading path formulations. These improvements aim to enhance the accuracy and reliability of cyclic stress-strain models for FRP-confined concrete columns, contributing to their effective application in structural design and seismic resilience.

Keywords

FRP

Confinement

Concrete column

Cyclic behavior

Stress-strain model

Subjects

Structural Engineering

[1] Y. Moodi, "Providing Models of the Compressive Strength of Square and Rectangular (S/R) Concrete Confined Using Genetic Programming," Numerical Methods in Civil Engineering, vol. 9, no. 3, pp. 16-27, 2025, doi: https://doi.org/10.61186/NMCE.2312.1040.

[2] A. Ilki and N. Kumbasar, "Behavior of damaged and undamaged concrete strengthened by carbon fiber composite sheets," Structural Engineering and Mechanics, vol. 13, no. 1, pp. 75-90, 2002, doi: https://doi.org/10.12989/sem.2002.13.1.075.

[3] T. Ozbakkaloglu and E. Akin, "Behavior of FRP-Confined Normal- and High-Strength Concrete under Cyclic Axial Compression," Journal of Composites for Construction, vol. 16, no. 4, pp. 451-463, 2012, doi: https://doi.org/10.1061/(ASCE)CC.1943-5614.0000273.

[4] V. Valdmanis, L. De Lorenzis, T. Rousakis, and R. Tepfers, "Behaviour and capacity of CFRP-confined concrete cylinders subjected to monotonic and cyclic axial compressive load," Structural Concrete, vol. 8, no. 4, pp. 187-200, 2007, doi: https://doi.org/10.1680/stco.2007.8.4.187.

[5] M. R. Shokrzadeh and F. Nateghi-Alahi, "Evaluation of hybrid NSM-CFRP technical bars and FRP sheets for seismic rehabilitation of a concrete bridge pier," Bridge Structures, vol. 18, no. 3-4, pp. 75-88, 2023, doi: https://doi.org/10.3233/brs-290180.

[6] M. r. Shokrzadeh, M. Sharifi, and F. Nateghi Alahe, "Seismic Retrofitting of Concrete Beam-Column Connections: Numerical study FRP Strip and NSM Technique," Journal of Seismology and Earthquake Engineering, vol. 26, no. 3, pp. 25-40, 2024, doi: https://doi.org/10.48303/jsee.2024.2031006.1099.

[7] M. R. Shokrzadeh, A. Aziminejad, and A. S. Moghaddam, "Evaluation of various FRP strengthening configurations for RC beam-column joints," Bridge Structures, vol. 20, no. 1-2, pp. 71-91, 2024, doi: https://doi.org/10.3233/brs-240223.

[8] Y. Shao, Z. Zhu, and A. Mirmiran, "Cyclic modeling of FRP-confined concrete with improved ductility," Cement and Concrete Composites, vol. 28, no. 10, pp. 959-968, 2006, doi: https://doi.org/10.1016/j.cemconcomp.2006.07.009.

[9] L. Lam, J. G. Teng, C. H. Cheung, and Y. Xiao, "FRP-confined concrete under axial cyclic compression," Cement and Concrete Composites, vol. 28, no. 10, pp. 949-958, 2006, doi: https://doi.org/10.1016/j.cemconcomp.2006.07.007.

[10] L. Lam and J. G. Teng, "Stress–strain model for FRP-confined concrete under cyclic axial compression," Engineering Structures, vol. 31, no. 2, pp. 308-321, 2009, doi: https://doi.org/10.1016/j.engstruct.2008.08.014.

[11] Z. Wang, D. Wang, S. T. Smith, and D. Lu, "Experimental testing and analytical modeling of CFRP-confined large circular RC columns subjected to cyclic axial compression," Engineering Structures, vol. 40, pp. 64-74, 2012, doi: https://doi.org/10.1016/j.engstruct.2012.01.004.

[12] Z. Wang, D. Wang, S. T. Smith, and D. Lu, "CFRP-Confined Square RC Columns. II: Cyclic Axial Compression Stress-Strain Model," Journal of Composites for Construction, vol. 16, no. 2, pp. 161-170, 2012, doi: https://doi.org/10.1061/(asce)cc.1943-5614.0000246.

[13] T. Yu, B. Zhang, and J. G. Teng, "Unified cyclic stress–strain model for normal and high strength concrete confined with FRP," Engineering Structures, vol. 102, pp. 189-201, 2015, doi: https://doi.org/10.1016/j.engstruct.2015.08.014.

[14] H. Ziaadiny and R. Abbasnia, "Unified cyclic stress‐strain model for FRP‐confined concrete circular, square and rectangular prisms," Structural Concrete, vol. 17, no. 2, pp. 220-234, 2016, doi: https://doi.org/10.1002/suco.201500128.

[15] M. Samaan, A. Mirmiran, and M. Shahawy, "Model of Concrete Confined by Fiber Composites," Journal of Structural Engineering, vol. 124, no. 9, pp. 1025-1031, 1998, doi: https://doi.org/10.1061/(asce)0733-9445(1998)124:9(1025).

[16] L. Lam and J. G. Teng, "Design-oriented stress–strain model for FRP-confined concrete," Construction and Building Materials, vol. 17, no. 6-7, pp. 471-489, 2003, doi: https://doi.org/10.1016/s0950-0618(03)00045-x.

[17] R. Abbasnia, R. Ahmadi, and H. Ziaadiny, "Effect of confinement level, aspect ratio and concrete strength on the cyclic stress–strain behavior of FRP-confined concrete prisms," Composites Part B: Engineering, vol. 43, no. 2, pp. 825-831, 2012, doi: https://doi.org/10.1016/j.compositesb.2011.11.008.

[18] R. Abbasnia, F. Hosseinpour, M. Rostamian, and H. Ziaadiny, "Effect of corner radius on stress–strain behavior of FRP confined prisms under axial cyclic compression," Engineering Structures, vol. 40, pp. 529-535, 2012, doi: https://doi.org/10.1016/j.engstruct.2012.03.020.

[19] R. Abbasnia and H. Ziaadiny, "Behavior of concrete prisms confined with FRP composites under axial cyclic compression," Engineering Structures, vol. 32, no. 3, pp. 648-655, 2010, doi: https://doi.org/10.1016/j.engstruct.2009.11.011.

[20] R. Abbasnia and H. Ziaadiny, "Behavior of FRP confined rectangular prisms under cyclic loading," MSc., Department of Civil Engineering, Iran University of Science and Technology, Tehran, Iran, 2013.

[21] R. Abbasnia and H. Ziaadiny, "Behavior and modeling of FRP confined concrete rectangular prisms under axial cyclic compression," PhD, Department of Civil Engineering, Iran University of Science and Technology, Tehran, Iran, 2013.

[22] H. Ziaadiny, R. Abbaszadeh, V. Razavinasab, and S. M. Elhamnike, "Behaviour of preloaded concrete cylinders confined by fibre-reinforced polymer composites," Proceedings of the Institution of Civil Engineers - Structures and Buildings, vol. 175, no. 9, pp. 697-708, 2022, doi: https://doi.org/10.1680/jstbu.20.00001.

[23] R. Abbasnia and H. Ziaadiny, "Experimental investigation and strength modeling of CFRP-confined concrete rectangular prisms under axial monotonic compression," Materials and Structures, vol. 48, no. 1-2, pp. 485-500, 2013, doi: https://doi.org/10.1617/s11527-013-0198-y.

[24] J. G. Teng, T. Jiang, L. Lam, and Y. Z. Luo, "Refinement of a Design-Oriented Stress–Strain Model for FRP-Confined Concrete," Journal of Composites for Construction, vol. 13, no. 4, pp. 269-278, 2009, doi: https://doi.org/10.1061/(asce)cc.1943-5614.0000012.

[25] J. Sakai and K. Kawashima, "Unloading and Reloading Stress–Strain Model for Confined Concrete," Journal of Structural Engineering, vol. 132, no. 1, pp. 112-122, 2006, doi: https://doi.org/10.1061/(asce)0733-9445(2006)132:1(112).

[26] H. Ziaadiny, "Plastic strain and stress deterioration of FRP-confined concrete prisms under axial cyclic compression," Materials and Structures, vol. 49, no. 4, pp. 1157-1164, 2015, doi: https://doi.org/10.1617/s11527-015-0565-y.