Composites: Part B 43 (2012) 2135–2142

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Composites: Part B

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Thermal-stress analysis of RC beams reinforced with GFRP bars

R.A. Hawileh ⇑, M.Z. NaserDepartment of Civil Engineering, The American University of Sharjah, P.O. Box 26666, Sharjah, UAE

a r t i c l e i n f o

Article history:Received 13 August 2011Received in revised form 8 November 2011Accepted 5 March 2012Available online 19 March 2012

Keywords:A. Glass fibresB. ThermomechanicalC. Computational modelingC. Finite element analysis (FEA)

1359-8368/$ - see front matter � 2012 Elsevier Ltd. Ahttp://dx.doi.org/10.1016/j.compositesb.2012.03.004

⇑ Corresponding author. Tel.: +971 6 515 2496; faxE-mail address: rhaweeleh@aus.edu (R.A. Hawileh

a b s t r a c t

This paper aims to develop a 3D nonlinear finite element (FE) model that is capable of accurately predict-ing the performance of reinforced concrete (RC) beams reinforced with internal Glass Fiber-ReinforcedPolymer (GFRP) bars when exposed to fire loading. The developed FE model is based on tested experi-mental data collected from the open literature. The model accounts for the variation in the thermaland mechanical constituent materials with temperature associated with the RC beam. To study the heattransfer mechanism and mechanical behavior of the RC beam, transient thermal-stress finite elementanalysis is performed using the ANSYS. It was shown that the FE predicted temperature and mid-spandeflection results are in a good agreement with that of the measured experimental data. The validatedFE model is used to conduct a parametric study to investigate the effect of the different parameters onthe flexural performance of the reinforced beam specimens. The parametric study consisted of varyingthe concrete cover thickness as well as exposing the FE model to different fire curves. It is concluded thatsuccessful FE modeling of this structure would provide an economical and alternative solution to expen-sive and time consuming experimental testing. Other observations and recommendations are alsodiscussed.

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1. Introduction

Recently, several experimental and analytical research projectshave been focused on the use of Fiber Reinforced Polymer (FRP)materials as internal bars to reinforce structural concrete membersat ambient room temperature [1–4]. Their high strength to weightratio, ease of installation and resistance to corrosion are consideredone of the many advantageous of using FRP materials instead of or-dinary steel reinforcement [5]. Because of their low glass tempera-ture and complex natural composition, it is demonstrated that FRPmaterials do not perform adequately under elevated temperaturesdue to their rapid loss of mechanical properties and susceptible tocombustion [6–9]. Hence, the performance of strengthened or rein-forced structural members with FRP materials under fire scenariosdraws many questions and imposes doubts in this research area.Unfortunately, limited experimental investigations have been con-ducted in the previous years due to the expensive experimental set-ups, tremendous amount of preparation and shortage of specializedfacilities [8]. Thus, the lack of knowledge regarding the perfor-mance of such materials under thermal effects warrants furtherexperimental, numerical and analytical investigations.

One key difference between the behavior of externally bondedFRP strengthening systems and internally embedded FRP barsunder fire scenarios is the lack of oxygen in the later, which would

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inhibit the burning of the FRP bars. Until, the increase in tempera-ture reaches the resin’s glass temperature then, the resin matrixstarts to soften which would reduce the amount of stress trans-ferred from the concrete to the embedded fibre reinforcement.Such phenomena would result in the increase of crack widthsand initiation of large deflections [9]. In addition, researchers [9]tried to develop temperature-dependant relationships relatingthe degradation of mechanical material properties of FRP materialswhen exposed to elevated temperatures. Saafi [9] proposed tem-perature dependent relationships to mimic the degradation ofthe mechanical material properties of different FRP and steel barsunder high temperatures effects.

Sadek et al. [10] compared in an experimental program the fireresistance endurance of RC beams reinforced with steel and GFRPbars as well as the effect of concrete compressive strength. In theirexperimental program, the beams were loaded up to 60% of theirultimate loads during the course of the fire test. The fire loadingwas simulated using the ASTM E119 [6] temperature–time firecurve. The dominant failure mode was mainly the fire penetrationthrough the wide cracks developed during testing. Large reductionin fire resistance due to the use of GFRP bars was observed com-pared to the beam reinforced with steel bars. It is worth mention-ing that Sadek et al. [10] used 25 mm concrete cover to the flexuralreinforcements, which contributed to the low performance ob-served in their experimental program.

Abbasi and Hogg [11] conducted two full scale fire tests on RCbeams reinforced with Glass Fibre Reinforced Polymer (GFRP) bars

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as their main flexural reinforcement while stirrups made of steeland GFRP were used separately as shear reinforcements. A concretecover to the flexural reinforcement of 75 mm was used. The beamswere fully loaded up to concrete cracking threshold limit and sub-jected to the ISO834 fire curve. The beams were designed accord-ing to Eurocode 2 [12] and ACI-440 [13] procedures. Severalthermocouples at different locations were used to measure the dif-ferent temperatures across the beam’s sections. The beam rein-forced with the steel stirrups achieved 128 min fire endurancewhile the beam reinforced with GFRP stirrups achieved 94 min.Both beams managed to pass the failure criteria under load bearingcapacity that is based on BS 476: Part 20 standard [14]. The failurecriterion was achieved by limiting the mid-span deflection to beless than L/20. In addition, the GFRP RC beams passed the buildingregulations for fire safety by withstanding the fire test more than90 min. It was concluded that the 70 mm concrete cover to themain flexural reinforcement managed to significantly enhancetheir fire resistance of the tested RC beam specimens with GFRPreinforcement.

The authors developed in previous studies [15,16] the perfor-mance of strengthened RC beams with externally bonded CFRPplates when subjected to fire loading. The objective of this studyis to develop a FE model that is capable of predicting the fire perfor-mance of RC beams with GFRP bars subjected to the standardISO834 [17] curve with reasonable accuracy. A coupled thermal-stress analysis will be simulated using the FE code ANSYS [18,19].The FE model is based on tested experimental data collected fromAbbasi and Hogg [11]. A parametric study is also conducted toinvestigate the influence the effect of the cover thickness and differ-ent fire curves on the performance of the RC beam specimens.

2. Analysis methodology

The steps used in the FE model development and thermal-stressanalysis of this structural member are:

1. Building a 3D FE model of the RC beam having the same geom-etry, materials (Concrete and GFRP bars) and boundary condi-tions, and loading. In order to perform thermal-stress analysisthermal and structural elements are required. Thus, two modelswere developed consisting of thermal and structural elements,respectively.

2. The transient temperature versus time ISO834 [17] fire curve isapplied in the thermal model to the soffit and vertical sides ofthe GFRP RC beam.

3. Validate the developed FE thermal model by comparing the pre-dicted and measured temperature at different locations withinthe beam cross section taken at mid-span.

4. A gravity load is applied to the top face of the beam in thedeveloped structural model to simulate the service dead andlive loads during fire exposure. The predicted deflection dueto gravity loads is compared to the measured experimental datain order to validate the structural behavior of the model. Tem-perature nodal loads obtained from the thermal analysis of Step2 are applied to the structural model at specified time points(load steps and substeps). This will result in capturing thedeformation history along the entire structure during thecourse of fire exposure.

5. Compare the predicted and measured mid-span deflection forthe entire fire exposure to evaluate the performance of thedeveloped FE model.

6. The validated and verified FE model is extended to a parametricstudy to investigate the effect of concrete cover thickness anddifferent standard fire curves on the overall performance ofthe GFRP RC beam.

3. Mathematical modeling

The 3D transient heat transfer governing equation as a functionof time is presented in Eq. (1). Eq. (1) is derived from the Law ofConservation of Energy which states that the total inflow of heatin a unit time across a certain body must be equal to the total out-flow per unit time for the same body [20]. Furthermore, Eq. (1)could be solved giving initial and boundary conditions on a partor all the boundary of the domain. The initial conditions definethe temperature distribution over the domain at the beginning ofthe heat transfer (i.e. at t = 0). The initial and boundary conditionsare given by Eqs. (2) and (3), respectively.

qc@T@t¼ k

@2T@x2 þ k

@2T@y2 þ k

@2T@z2 þ S ð1Þ

Tðx; y; z;0Þ ¼ T0ðx; y; z;0Þ ð2Þ

�k@T@u¼ hcðTs � Tf Þ þ hrðTs � Tf Þ ð3Þ

where q is the density, c is the specific heat, k is the conductivity, Sis the internally generated heat on unit volume per unit time, T isthe temperature gradient, t is time, u is the direction of heat, hc isthe heat transfer coefficient of solid surface, Ts is the temperatureof solid surface, Tf is the temperature of fluid and hr is the radiationheat transfer coefficient given by

hr ¼ resðT2s þ T2

f ÞðTs þ Tf Þ ð4Þ

where es is the emissivity of the surface in question and r is theStefan–Boltzmann constant 5.669 � 10�8 W/m2 K4 (0.1714 � 10�8

BTU/h ft2 R4).The FE formulation is based on the Galerkin weighted residual

method in which each element is divided yielding the first orderdifferential equation presented by [20].

½k�fTng þ ½c�fTng ¼ fFng ð5Þ

where [k] is the element heat conduction and convection matrix, [c]is the element heat capacity matrix, Tn is the element nodal temper-ature vector, Fn is the element nodal heat input vector.

The system is then summed up to collect the individual ele-ments yielding the global system shown in the following equation:

½K�fTg þ ½C�fTg ¼ fFg ð6Þ

where [K] is the global heat conduction and convection matrix, [C] isthe global heat capacity matrix, T is the global nodal temperaturevector, F is the global nodal heat input vector.

In the structural simulation Eq. (7) presents the equation thatrelates the stresses with mechanical and thermal strain.

frg ¼ ½D�fe� eTg ð7Þ

where {r} is the stress vector, [D] is the stiffness matrix used in thestructural simulation, {e} is the strain vector and {eT} is the temper-ature related total strain.

4. Finite element model development

The developed 3D FE model has the same geometry, materialproperties, boundary conditions and loading as the GFRP RC beamstested by Abbasi and Hogg [11]. The RC beams with GFRP bars havea rectangular cross-section with height and width of 400 mm and350 mm, respectively. The effective depth was 325 mm and theclear concrete cover from the soffit of the beam to the flexuralreinforcement was 70 mm. The total length of the beam was4400 mm with an effective span length of 4250 mm as shown inFig. 1. The beams were reinforced with nine 12.7 mm diameter

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(Agfrp = 144.85 mm2) GFRP bars, seven at the tension side and twoat the compression zone of the beam’s cross-section. In addition,9 mm diameter stirrups were used as shear reinforcements spacedcenter to center at 160 mm.

The FE model was developed and simulated using the FE soft-ware, ANSYS 11.0 [18]. Fig. 2 shows a detailed view of the devel-oped FE model. One quarter of the RC beam specimen wasmodeled taking advantage of the symmetrical nature of the geom-etry, loading and boundary conditions resulting in a tremendousreduction in the computational time. The symmetrical boundaryconditions were developed by applying vertical restrains (rollers)in the two planes of symmetry, the transverse and longitudinaldirections.

Different thermal and structural element types were used in thedevelopment of the FE model. The thermal elements used were SO-LID70 and LINK33 [18] and the structural elements used in thestress analysis were SOLID65, SOLID45 and LINK8 [18].

Both concrete material and steel supports were modeled in thethermal simulation using SOLID70 [18]. SOLID70 has a 3-D thermalconduction capability and eight nodes with a single degree of free-dom (SDF) at each node, defined as temperature. The GFRP barswere modeled using the thermal spar element, LINK33 [18].LINK33 is a uniaxial element with the ability to conduct heat be-tween its two nodes. The element has a one SDF, temperature at

(a) Details of the tested

(b) Loading set

Fig. 1. Geometry and lo

each node. In addition, both thermal elements are applicable to a3-D steady-state or transient thermal analysis [18].

As for the structural simulation, the concrete material was mod-eled using SOLID65 [18]. SOLID65 is used for the 3-D modeling ofsolids with or without reinforcing bar. The element is capable ofcracking in tension and crushing in compression. The element isdefined by eight nodes, having three degrees of freedom at eachnode: translations in the nodal x, y, and z directions. LINK8 [18]is used to model the GFRP bars. LINK8 is a spar uniaxial tension–compression element with three degrees of freedom at each node:translations in the nodal x, y, and z directions. The element hasplasticity, creep, swelling, stress stiffening, and large deflectioncapabilities. The supports were modeled as rigid supports usingSOLID45 [18] elements. SOLID45 [18] is generally used for the 3-D modeling of solid structures and is defined by eight nodes havingthree degrees of freedom at each node: translations in the nodal x,y, and z directions [18]. Since, there has not been reported anybond-slip failure in the experiment conducted by Abbasi and Hogg[11], and according to recent study by Rafi et al. [20], perfect bondwas assumed between the GFRP bars and surrounding concrete byallowing the elements to share the same nodes. Further investiga-tion on the bond-slip between GFRP bars and concrete at elevatedtemperatures is warranted. The total number of elements used inthe developed model was 20500 elements.

RC beams

-up

ading set-up [11].

First plane of symmetry

Second plane of symmetry

First plane of symmetry

(a) Isometric view (b) Cross section view

(c) Side view

Uniformly distributed load

Second plane of symmetry

GFRP Bars

Fig. 2. The developed FE model.

Fig. 3. Thermal material properties of concrete material.

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5. Material constitutive models

It is evident that most materials’ mechanical properties tend todegrade at elevated temperatures [5,7,8]. The developed FE modelherein requires temperature-dependant mechanical and thermalmaterial properties as inputs. Table 1, provides mechanical andthermal properties for the concrete and GFRP bars used in thisstudy at ambient room temperature.

There have been many well documented data on the behavior ofRC structural members at elevated temperatures [20–26]. Thethermal material properties for density, specific heat and thermalconductivity of concrete as a function of temperature were takenfrom Eurocode 2 [12] and shown in Fig. 3. The coefficient of ther-mal expansion as a function of increasing temperature was takenfrom a study conducted by other researchers [7] and presentedin Eq. (8).

ac;T ¼ ð0:008Tc þ 6Þ � 10�6 ð8Þ

Where ac,T is the coefficient of thermal expansion (1/�C), Tc is tem-perature (�C).

The thermal material properties in the transient analysis for theGFRP bar material were taken at room temperature due to the lackof experimental thermal material data for this material at elevatedtemperature.

In the structural stress simulation, the degradation of bothstrength and stiffness of concrete was accommodated by usingthe proposed reduction factors of Eurocode 2 [12] and factors givenby Zhou and Vecchio [26]. The concrete material was modeledusing the nonlinear constitutive concrete material model ofWilliams and Warnke [27]. This model takes into account the non-linearity of concrete in tension by allowing the concrete elementsto crack upon reaching their ultimate tensile strength and to crushonce they reach the maximum compressive strength. It should benoted that neither of the beams experienced any crushing of the

Table 1Material properties at ambient temperatures.

Material Ex (GPa) t Ko (W/mm K) Co (J/kg K) aL (1/K�) aT (1/�K) q (kg/mm3)

Concrete 30.5 0.20 2.7 � 10�3 722.8 6.08 � 10�6 – 2.32 � 10�6

GFRP 40.8 0.28 4.0 � 10�5 1310 6.58 � 10�6 33.7 � 10�6 1.60 � 10�6

Fig. 4. Concrete material stress–strain curves at elevated temperatures [15,16]. Fig. 5. The ISO834 fire curve [17].

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compression concrete and thus crushing was not considered as amain failure criteria. Up to the first crack, concrete material is trea-ted as an isotropic elastic material and becomes orthotropic afterthe initiation of cracks. Once a concrete element cracks, the mod-ulus of elasticity is set to zero in the direction parallel to the prin-cipal tensile stress direction [27].

The open and close crack shear transfer coefficients, bt and bc

are additional parameters required for the concrete constitutivematerial model [27]. Typical shear transfer coefficients are takenas zero when there is a total loss of shear transfer representing asmooth crack and 1.0 when there is no loss of shear transfer repre-senting a rough crack [18]. The values of bt and bc in the developedmodel are assumed to be 0.3 and 0.5, respectively [15,16].

To model the concrete nonlinearities in compression, multi-lin-ear stress–strain curves as a function of increasing temperaturewere used. Fig. 4 shows the temperature dependent compressivestress–strain curves produced according to the reduction factorsgiven by Zhou and Vecchio [26]. The concrete tensile rupture stressis taken as 0.62

ffiffiffiffif 0c

pwhere f 0c is the compressive strength of con-

crete. Once the concrete material reaches its tensile peak rupturestress, a tensile stiffness multiplier of 0.6 is used to simulate a sud-den drop of the tensile stress to 60% of the rupture stress, followedby a linearly descending curve to zero stress at a strain value of sixtimes the strain corresponding to the concrete rupture stress.

The GFRP bars material is assumed to behave elastically up tofailure. The reduction factors of both ultimate tensile strength(Kr) and modulus of elasticity (KE) were calculated according toAbbasi and Hogg [29] and presented in Eqs. (9) and (10).

Kr ¼ 1� 0:0025DT ð9Þ

KE ¼ 1� 0:0017DT ð10Þ

where DT = T�20 �CIt should be noted that the GFRP material is very sensitive at

elevated temperatures in which it loses most of its initial stiffnessat 500 �C [5,7].

It should be noted that there have been a lot of debate on defin-ing a critical temperature for FRP bars [9,20,28,29]. In this study,failure of the beams’ specimens is defined when the temperaturein the GFRP bars reaches 462 �C, which was the measured temper-ature of the GFRP bars at failure in the experimental program ofAbbasi and Hogg [11].

6. Loading and boundary conditions

The developed FE model must go under two stages, transientthermal analysis and structural stress analysis. The first stage con-sists of performing thermal transient analysis, in which the BS 476:

Part 20 [14] which is equivalent to the ISO834 [17] temperaturecurve was applied as nodal temperatures at the sides and bottomsurface of the RC beams’ specimens. The nodal temperatures wereapplied in terms of load steps. Each load step is composed of sev-eral smaller substeps that are solved using the Newton–Raphsontechnique [19]. The ISO834 fire curve is shown in Fig. 5.

Although, it was shown that the dominant heat transfer phe-nomenon inside a fire chamber is radiation [8,21], but the fact thatthe fire nozzles in the furnace are very close to the tested beams,the authors applied the average furnace temperature directly tothe soffit and sides of the developed 3D RC beam [16,17]. This ap-proach seems to result in a good matching with the temperaturereadings recorded in the experimental program done by Abbasiand Hogg [11] that will be discussed in the subsequent section.

The second stage consists of performing structural stress analy-sis to predict the performance of the RC beam specimens due to theapplied gravity service load and the obtained temperature distri-bution from the thermal analysis of stage 1. The thermal loadsare applied to the structural model at specified load steps and sub-steps from the results of the thermal analysis. The beam was mod-eled as simply supported. Symmetrical boundary conditions issimulated by applying rollers that restrains translation in the planeperpendicular to the axis of symmetry. Two planes of symmetrywere applied to the quarter model as shown in Fig. 2. The serviceloads used in the experimental program was 40 kN and was ap-plied in the FE structural model as uniformly distributed load asshown in Fig. 2.

In this study, automatic time stepping option is turned on topredict and control the load step size. At the end of each load step,convergence is achieved by Newton–Raphson equilibrium itera-tions [19] within tolerance limits of the convergence criteria basedon force and displacement. A tolerance value of 0.1 [15,16] wasused in the structural nonlinear analysis of this study.

7. Results and discussions

7.1. Validation model

The developed FE model is validated by comparing the pre-dicted results with that of the measured experimental data.Fig. 6 draws a comparison between the average predicted and mea-sured temperature in the flexural GFRP reinforcements for the en-tire fire exposure. It is clear from Fig. 6 that there is a goodagreement between the measured and predicted temperaturesthroughout the fire test. The maximum average deviation betweenthe predicted and measured results is within 15 �C. Furthermore,Fig. 7 shows a comparison of the mid-span deflection history be-tween the measured and predicted results during the course of

Fig. 6. Comparison between the average temperatures measured and predicted inthe GFRP reinforcements.

Fig. 7. Comparison between the deflection history of the measured and simulatedresults.

Fig. 8. Comparison between the effects of using different concrete cover thick-nesses on the thermal responses.

Fig. 9. Comparison between the effects of using different concrete cover thick-nesses on the mid-span deflection responses.

Table 2Effect of different concrete cover thickness.

FE model Designation Time to failure(min)

Deflection atfailure (mm)

FE-70 mm Validation model 130 100FE-65 mm 65 mm cover 120 76FE-60 mm 60 mm cover 87.0 50.8FE-45 mm 45 mm cover 57.0 48.0

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the fire testing. The GFRP RC beam specimen failed after 128 min offire exposure by a sudden increase in deflection that caused failureof the beam specimen. Similarly, the predicted time to failure inthe developed FE model was reached after 130 min due to largemidspan deflection that causes divergence in the solution.

7.2. Parametric study

A parametric study was carried out using the developed andvalidated FE model to investigate the influence of the concretecover thickness and the effect of different applied fire curves.

7.2.1. Effect of concrete cover thicknessThe effect of using different concrete cover thicknesses was

taken into account by altering the concrete cover thickness from70 to 65, 60 and 45 mm. The time to failure is assumed to occurwhen the average temperature in the GFRP bars reaches the criticalGFRP temperature of 462 �C. Figs. 8 and 9 draw a comparison be-tween the effect of using different concrete cover thicknesses onthe thermal and deflection responses. In addition, Table 2 liststhe predicted midspan deflection and duration to failure for eachmodel. As expected, the decrease of the cover thickness would in-crease the temperature at the GFRP flexural reinforcement whichin turn increases the loss of mechanical properties and initiatesearly failure times. It is clear from Table 2 that the time to failurewas 130 min, 120 min, 87 min and 57 min for the beams havingconcrete covers of 70 mm, 65 mm, 60 mm and 45 mm, respec-tively. Thus, the fire endurance of the FE models was 7.7%, 22.3%and 49.2% less than the validation model that had a concrete cover

of 70 mm. This shows that the use of a concrete cover of 65 mm oreven 60 mm (87 min to failure) would pass the BS 476: Part 20 [14]and other building codes requirements [11] requirements ofachieving more than 90 min fire endurance. Thus, it could be con-cluded that if a GFRP RC beam is to be designed to resist the ISO834[13] fire curve, a concrete cover of 65 mm is sufficient to protectthe GFRP bars during fire exposure.

7.2.2. Effect of different fire curvesThe performance of the RC beams is studied when subjected to

the Modified Hydrocarbon (HCM) [30] and a typical compartmentfire curve [31]. The HCM fire curve [30] was developed with a max-imum temperature of 1300 �C. It worth mentioning that the rapidincrease in the temperature of the HCM curve at the early stageswould cause a large thermal shock (gradient) to the surrounding

Table 3Effect of different fire curves.

FE model Designation Time tofailure(min)

Deflection atfailure (mm)

FE-ISO834 Validation model 130 100FE Modified

HydrocarbonExposed to Hydrocarbonfire curve

91.5 62.7

FE-Compartment Exposed to Compartment NA NA

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structure that arise from the rapid burning of petroleum and chem-ical fuels [30]. The compartment fire curve was chosen to representa fire scenario that is very severe and lasts for a short duration oftime, mainly for 35 min. The compartment (actual) fire curve[31] depends on many factors including room geometry, ventila-tions, fuel amount and type, etc. One main difference betweenthe standard and actual fire curves is that the later have a decayingportion which simulates the full consumption of fuel and/or pres-

Fig. 10. Different fire curves used in the study.

Fig. 11. Comparison between the effects of using different fire curves on thethermal response of the GFRP RC beam.

Fig. 12. Comparison between the effects of using different the different fire curveson the mid-span deflection responses.

fire curve

ence of fire fighters efforts. Fig. 10 shows the different fire curvesused in the parametric study of this investigation.

Figs. 11 and 12 draw a comparison between the effect of usingdifferent fire curves on the thermal and deflection responses of theGFRP RC beam specimens. In addition, Table 3 presents the pre-dicted midspan deflection and time to failure for each model. Itis clear from Table 3 that the time to failure was 91.5 min for thebeam exposed to the HCM fire curve which exceeds the 90 minrequirement of the BS476: Part 20 [14] code. Furthermore, it isclear from Fig. 11 that the GFRP RC beam exposed to the compart-ment fire curve did not fail during the entire exposure. Thus, it canbe concluded that the GFRP RC beams with a 70 mm cover can alsoresist the severe HCM fire exposure as well as the compartmentfire curve.

8. Summary and conclusions

A nonlinear 3D FE model was developed and validated againstthe experimental program conducted by other researchers to pre-dict the performance of RC beams reinforced with GFRP bars. Then,a parametric study was carried out to investigate the effect of con-crete cover and other fire curves on the performance of the beamspecimens. The following observations and conclusion were drawnbased on the numerical results of this study:

� The predicted thermal and deflection results of the developedFE model are in close agreement with the experimental testing.Thus, the developed model could be used as a valid tool to pre-dict the performance of GFRP reinforced concrete beams. It isclear that the developed FE model is capable of accurately cap-turing the behavior of the tested RC beams under the effects offire actions.� The fire endurance of FE models representing a concrete cover

of 45, 60 and 65 mm models was 49.2%, 22.3% and 7.7% lessthan the validation model with a concrete cover of 70 mm.� The fire endurance of FE models exposed to the Modified

Hydrocarbon fire curve was 29.6 less than that exposed to theISO834. This is mainly due to the severity of the ModifiedHydrocarbon fire curve fire curve.� The developed FE model could be used in future oriented para-

metric studies to investigate the effect of several parameters onthe performance of GFRP RC beams.

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