Finite element modelling of RC slabs retrofitted with CFRP strips under blast loading

oussama atoui, Azer Maazoun, David Lecompte, Bachir Belkassem, stijn matthys

Research output: Contribution to journalArticle


This paper presents nonlinear finite element (FE) simulations to predict the structural behavior of simply supported reinforced concrete (RC) slabs retrofitted with carbon fiber reinforced polymer (CFRP) as externally bonded reinforcement (EBR) and subjected to the blast loads in order to evaluate the effectiveness of using the CFRP strips as EBR for blast protection. The objective of this paper is to develop detailed numerical models in order to predict the blast response of non-retrofitted and retrofitted RC slabs during the inbound and rebound phases. A plastic material model including the strain rate effects of the material and able to predict the cracks is used to model the concrete. An elasto-plastic material model and an elastic material model are used to model the steel reinforcement and the CFRP strips, respectively. The bond interface between concrete and CFRP strip is simulated using a special contact algorithm including the strain rate effect at the interface between concrete and CFRP strip with failure criteria. The numerical results are validated by experimental tests. The maximum deflections, crack distribution and strain evolution in the steel reinforcement and in the CFRP strips found by the numerical analysis are in good agreement with the experiments. The concrete material model gives a good prediction of the blast response of the RC slab with and without EBR. Increasing the amount of the CFRP strip reduces the maximum deflection at the mid span of the slabs and the strain distribution in the steel reinforcement and in the CFRP strip. Parametric studies with respect to CFRP width and CFRP thickness are performed in order
to evaluate the effects on the blast response of the RC slabs.
Original languageEnglish
Article number113597
JournalEngineering Structures
Publication statusPublished - 1 Feb 2022

Bibliographical note

[1] Maazoun A, Belkassem B, Reymen B, Matthys S, Vantomme J, Lecompte D. Blast response of RC slabs with externally bonded reinforcement: Experimental and analytical verification. Compos Struct 2018;200:246–57.

[2] Mutalib AA, Hao H. Development of P-I diagrams for FRP strengthened RC
columns. Int J Impact Eng 2011;38(5):290–304.

[3] Buchan PA, Chen JF. Blast resistance of FRP composites and polymer strengthened concrete and masonry structures – A state-of-the-art review. Compos Part B Eng 2007;38(5-6):509–22.

[4] Muszynski LC, Purcell MR. Use of Composite Reinforcement to Strengthen
Concrete and Air-Entrained Concrete Masonry Walls against Air Blast. J Compos
Constr 2003;7(2):98–108.

[5] Lin X, Zhang YX. Parametric study of FRP-strengthened reinforced concrete panels under blast loads. 6th Int Conf Comput Methods 2015:14–7. 10.1142/

[6] Mao L, Barnett S, Begg D, Schleyer G, Wight G. Numerical simulation of ultra high performance fibre reinforced concrete panel subjected to blast loading. Int J Impact Eng 2014;64:91–100.

[7] Orton SL, Chiarito VP, Minor JK, Coleman TG. Experimental Testing of CFRPStrengthened Reinforced Concrete Slab Elements Loaded by Close-In Blast. J Struct Eng 2014;140(2):04013060.

[8] Maazoun A, Matthys S, Belkassem B, Lecompte D, Vantomme J. Blast response of retrofitted reinforced concrete hollow core slabs under a close distance explosion. Eng Struct 2019;191:447–59.

[9] Tanapornraweekit G, Haritos N, Mendis P. Finite Element Simulation of FRP
Strengthened Reinforced Concrete Slabs Under Two Independent Air Blasts 2010;1:469–88.

[10] Yao J, Teng JG, Chen JF. Experimental study on FRP-to-concrete bonded joints. Compos Part B Eng 2005;36(2):99–113. 2004.06.001.

[11] Yuan H, Teng JG, Seracino R, Wu ZS, Yao J. Full-range behavior of FRP-to-concrete bonded joints. Eng Struct 2004;26(5):553–65. engstruct.2003.11.006.

[12] Buyukozturk O, Gunes O, Karaca E. Progress on understanding debonding
problems in reinforced concrete and steel members strengthened using FRP
composites. Constr Build Mater 2004;18(1):9–19.

[13] Mazzotti C, Savoia M, Ferracuti B. An experimental study on delamination of FRP plates bonded to concrete. Constr Build Mater 2008;22(7):1409–21.

[14] Yuan C, Chen W, Pham TM, Hao H, Cui J, Shi Y. International Journal of Solids and Structures Dynamic interfacial bond behaviour between basalt fiber reinforced polymer sheets and concrete. Int J Solids Struct 2020;202:587–604.

[15] Maazoun A, Matthys S, Belkassem B, Atoui O, Lecompte D. Experimental study of the bond interaction between CFRP and concrete under blast loading. Compos Struct 2021;277:114608.

[16] Mosalam KM, Mosallam AS. Nonlinear transient analysis of reinforced concrete slabs subjected to blast loading and retrofitted with CFRP composites. Compos Part B-Eng 2001;32(8):623–36.

[17] Nam J-W, Kim H-J, Kim S-B, Yi N-H, Kim J-H. Numerical evaluation of the retrofit effectiveness for GFRP retrofitted concrete slab subjected to blast pressure. Compos Struct 2010;92(5):1212–22.

[18] Kong X, Qi X, Gu Y, Lawan IA, Qu Y. Numerical evaluation of blast resistance of RC slab strengthened with AFRP. Constr Build Mater 2018;178:244–53.

[19] De LL, La TA. Bond of FRP laminates to concrete under impulse loading: a simple model. Proc. Int. Symp. Bond Behav. FRP Struct. 2005:495–500.

[20] Thiagarajan G, Williamson E. Analytical and Finite Element Concrete Material
Models - Comparison of Blast Response Analysis of One Way Slabs with
Experimental Data. 2016.

[21] Lee H-K, Kim S-E. Structural behavior of SC panel subjected to impact loading using finite element analysis. Nucl Eng Des 2015;295:96–105.

[22] Li J, Hao H. Numerical study of concrete spall damage to blast loads. Int J Impact Eng 2014;68:41–55.

[23] Li J, Wu C, Hao H. An experimental and numerical study of reinforced ultra-high performance concrete slabs under blast loads. Mater Des 2015;82:64–76. https://

[24] Wang W, Zhang D, Lu F, Wang S chuan, Tang F. Experimental study and numerical simulation of the damage mode of a square reinforced concrete slab under close-in explosion. Eng Fail Anal 2013;27:41–51. 10.1016/j.engfailanal.2012.07.010.

[25] Xu K, Lu Y. Numerical simulation study of spallation in reinforced concrete plates subjected to blast loading 2006;84:431–8. 10.1016/j.compstruc.2005.09.029.

[26] Ottosen Niels Saabye. A Failure Criterion for Concrete. J Eng Mech Div 1977;103(4):527–35.

[27] Schwer L. An Introduction to the Winfrith Concrete Model. Geomaterial Model. 2011:1–37.

[28] Broadhouse BJ. AEA Technology. Winfrith Concrete Model in LS-DYNA3D. 1995.

[29] Schwer L. Winfrith Concrete Model Strain Rate Options. 2010.

[30] LS-Dyna Keyword user’s manual. vol. I. 2016.

[31] Broadhouse BJ, Neilson AJ. Modelling Reinforced Concrete Structures in DYNA3D. AEE Winfrith 1987;AEEW-M 246.

[32] Kilic Sami A. Numerical Study on the Uplift Response of RC Slabs Subjected to Blasts. J. Perform. Constr. Facil. 2017;31(3):04016105.

[33] Hughes WJ. Simulating Laminated Composite Materials Using LS-DYNA Material Model MAT54 : Single-Element Investigation. 2015.

[34] LS-Dyna keyword user’s manuel. KEYWORD USER ’ S MANUAL VOLUME II. vol. II.2016.

[35] Chen H. An Introduction to *CONSTRAINED_BEAM_IN_SOLID. vol. 1. 2012.

[36] Maazoun A, Vantomme J, Matthys S. Damage assessment of hollow core reinforced and prestressed concrete slabs subjected to blast loading. vol. 00, 2017, p. 0–7.

[37] Teng JG, Smith ST, Yao J, Chen JF. Intermediate crack-induced debonding in RC beams and slabs. Constr Build Mater 2003;17(6-7):447–62.

[38] Huo J, Liu J, Dai X, Yang J, Lu Y, Xiao Y, et al. Experimental Study on Dynamic
Behavior of CFRP-to-Concrete Interface. J Compos Constr 2011:1–12. https://doi. org/10.1061/(ASCE)CC.1943-5614.0000677.

[39] Shen D, Shi X, Ji Y, Yin F. Strain rate effect on bond stress – slip relationship
between basalt fiber-reinforced polymer sheet and concrete. J Reinf Plast Compos

[40] Malvar LJ, Crawford JE. Dynamic increase factor for concrete. Twenty-Eighth
DDESB Semin., Orlando: 1998.


  • Carbon fiber reinforced polymer
  • Blast response
  • RC slab
  • Numerical analysis


Dive into the research topics of 'Finite element modelling of RC slabs retrofitted with CFRP strips under blast loading'. Together they form a unique fingerprint.

Cite this