Analysis of RC Continuous Beams Strengthened with FRP Plates: A Finite Element Model
Strengthening of reinforced concrete (RC) beams with externally bonded fibre reinforced polymer (FRP) plates/sheets technique has become widespread in the last two decades. Although a great deal of research has been conducted on simply supported RC beams, a few studies have been carried out on continuous beams strengthened with FRP composites. This paper presents a simple uniaxial nonlinear finite-element model (UNFEM) that is able to accurately estimate the load-carrying capacity and the behaviour of RC continuous beams flexurally strengthened with externally bonded FRP plates on both of the upper and lower fibres. A 21-degree of freedom element is proposed with layer-discretization of the cross-sections for finite element (FE) modelling. Realistic nonlinear constitutive relations are employed to describe the stress-strain behaviour of each component of the strengthened beam. The FE model is based on nonlinear fracture mechanics. The interfacial shear and normal stresses in the adhesive layer are presented using an analytical uncoupled cohesive zone model with a mixed-mode fracture criterion. The results of the proposed FE model are verified by comparison with various selected experimental measurements available in the literature. The numerical results of the plated beams (beams strengthened with FRP plates) agreed very well with the experimental results. The use of FRP increased the ultimate load capacity up to 100 % compared with the non-strengthened beams as occurred in series (S). The major objective of the current model is to help engineers’ model FRP-strengthened RC continuous beams in a simple manner.
ACI 440, Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. Technical Report, American Concrete Institute. 2011.
CEB-FIB Model Code 90, Thomas Telford Eds., London, 1993.
JSCE, Recommendations for upgrading of concrete structures with use of continuous fiber sheets. Technical Report, Research Committee on Upgrading of Concrete Structures with Use of Continuous Fiber Sheets, Japanese Society of Civil Engineers, 2000.
Grace NF, Sayed GA, Soliman AK, Saleh KR. Strengthening Reinforced Concrete Beams Using Fiber Reinforced Polymer (FRP) Laminates. ACI Structural Journal 1999. p. 865-875.
Grace NF. Strengthening of negative moment region of RC beams using CFRP strips. ACI Structural Journal 2001; 3(98):347-358.
El-Refaie SA, Ashour, AF and Garrity SW. CFRP strengthened continuous concrete beams. in Proceedings of the Institution of Civil Engineers. Structures and buildings 2003; 156(4):395–404.
Ashour, AF, El-Refaie SA and Garrity SW. Flexural strengthening of RC continuous beams using CFRP laminates. Cement and Concrete Composite J 2004; 26(7):765–775.
Maghsoudi AA, Bengar H. Moment redistribution and ductility of RHSC continuous beams strengthened with CFRP. Turkish Journal of Engineering and Environmental Sciences 2009; 33:45-59.
Rahman M., Jumaat M. The Effect of CFRP laminates length for strengthening the tension zone of the reinforced concrete T-beam. Journal of scientific research & reports 2013; 2(2):626-640.
Aiello MA, Valente L, Rizzo A. Moment redistribution in continuous reinforced concrete beams strengthened with carbon-fiber-reinforced polymer laminates. Mechanics of composite materials 2007; 43(5):453-466.
Deifalla, A., Awad, A., and Elgarhy, M. “Effectiveness of externally bonded CFRP strips for strengthening flanged beams under torsion: An experimental study.”Journal of Engineering Structures, 2013; 56: 2065-2075.
Kotynia, R.; Cholostiakow, S. New proposal for flexural strengthening of reinforced concrete beams using CFRP T-shaped profiles. Polymers 2015, 7, 2461–2477.
Rahman, M.; Jumaat, M.Z.; Rahman, M.A.; Qeshta, I.M.I. Innovative hybrid bonding method for strengthening reinforced concrete beam in flexure. Constr. Build. Mater. 2015, 79, 370–378.
Elwan SK. Torsion strengtheing of RC beams using CFRP (Parametric Study). KSCE Journal of Civil Engineering. 2016:1-9.
Fakhreddine D, Youcef G, Yazid A, Li A. Strengthening in flexure–shear of RC beams with hybrid FRP systems: Experiments and numerical modeling. Journal of Reinforced Plastics& Composites. 2016: 17-25
Subhashree S. Strengthening of RC continuous beam using FRP sheet. Master Thesis No. 210CE2032, Department of Civil Engineering, National Institute of Technology Rourkela, Odisha, India, 2012.
Jerome DM, Ross CA. Simulation of the dynamic response of concrete beams externally reinforced with carbon-fiber reinforced plastic. Computers and Structures, 1997; 64(5):1129–1153.
Moller B, Graf W, Hoffmann A, Steinigen F. Numerical simulation of RC structures with textile reinforcement. Computers and Structures 2005; 83:1659–1688.
Camata G, Spacone E, Zarnic R. Experimental and nonlinear finite element studies of RC beams strengthened with FRP plates. Composites 2007; 38:277–288.
Zhang L, Teng JG. Finite element prediction of interfacial stresses in structural members bonded with a thin plate. Engineering Structures 2010; 32:459-471.
Kotynia R, Baky HA, Neale KW, Ebead UA. Flexural strengthening of RC beams with externally bonded CFRP systems: test results and 3D nonlinear FE analysis. Journal of Composite Construction ASCE 2008; 12(2):190–201.
Obaidat YT, Heyden S, Dahlblom O. The effect of CFRP and CFRP/concrete interface model when modelling retrofitted RC beams with FEM. Computers and Structures 2010;92:1391–1398.
Barbato M. Efficient finite element modeling of reinforced concrete beams retrofitted with fibre reinforced polymers. Computers and Structures 2009; 87:167–176.
Sakr MA. FE modeling of simply supported RC beams strengthened with FRP plates. 13th International conference on structural faults and repair, Edinburgh, UK, 2010.
Mander JB0, Priestley MJN, Park R. Theoretical stress-strain model for confind concrete. Journal of Structural Engineering (ASCE) 1998; 114(8):1804–1826.
Stevens NJ, Uzumeri SM, Collins MP, Will GT. Constitutive model for reinforced concrete finite element analysis. ACI Structural Journal 1991; 88(1):49-59.
Fragiacomo M, Amadio C, Macorini L. Finite–element model for collapse and long–term analysis of steel–concrete composite beams. Struct. Eng., ASCE 2004; 130(3):489–497.
Kafkalidis MS, Thouless MD. The effects of geometry and material properties on the fracture of single lap-shear joints. International Journal of Solids and Structures 2002; 39:4367–4383.
Li S, Thouless MD, Waas AM, Schroeder JA, Zavattieri PD. Mixed-mode cohesive-zone models for fracture of an adhesively bonded polymer-matrix composite. Engineering Fracture Mechanic 2006; 73:64–78.
Tvergaard V. Effect of fiber debonding in a whisker-reinforced metal. Material Science and Engineering 1990; 125:203–213.
Högberg JL. Mixed mode cohesive law. International journal of Fracture 2006; 141:549–559.
Guo ZG, Cao SY, Sun WM, Lin XY. Experimental study on bond stress-slip behaviour between FRP sheets and concrete. In: FRP in construction, proceedings of the international symposium on bond behaviour of FRP in structures 2005:77–84.
- There are currently no refbacks.
Copyright (c) 2016 Mohamed A. Sakr, Tarek M. Khalifa, Walid N. Mansour
This work is licensed under a Creative Commons Attribution 4.0 International License.