review article - hindawi

Review ArticleReview of Experimental Studies on Application of FRP forStrengthening of Bridge Structures

Wenliang Hu Yuan Li and Haoyun Yuan

School of Highway Changrsquoan University Xirsquoan 710064 China

Correspondence should be addressed to Wenliang Hu 2015021022chdeducn

Received 28 July 2020 Revised 3 September 2020 Accepted 21 December 2020 Published 30 December 2020

Academic Editor Antonio Caggiano

Copyright copy 2020 Wenliang Hu et al (is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

In recent years fiber-reinforced polymer (FRP) composites have been widely used as a new type of high-performance material inconcrete structures FRP composites have the advantages of high strength light weight and corrosion resistance Based on existingstudies in the literature this paper reviews the development and applications of FRP materials for the strengthening and re-habilitation of bridge structures (e types and properties of FRP composites are summarized and the applications and de-velopment of FRP sheets FRP bars FRP grids and prestressed FRP tendons for bridge structures are discussed Different types ofFRP composites result in different failure characteristics and bearing capacities Moreover this paper covers the FRPstrengthening methods and the response properties of the flexural performance bonding performance and ductility Significantconclusions regarding the strengtheningrepair of bridge structures with FRP composites are presented (e review details thecurrent state of knowledge and research on strengthening bridge structures with FRP composites and is helpful for betterunderstanding and establishing design criteria

1 Introduction

In recent years the degradation of concrete structures andsteel structures has become increasingly severe [1ndash4] notonly affecting the normal use and life of the structures butalso introducing significant safety hazards (e performancedegradation of bridge structures is directly affected byoverload corrosion fatigue and other adverse factorsTraditional concrete bridges and steel bridges quickly crackpeel and collapse under harsh conditions resulting inconsiderable economic losses Figure 1 shows the damage totraditional asphalt pavement on a steel deck (e criticalenvironmental and traffic conditions can affect the servicelife of traditional bridge decks Typically in such cases ofdamage to bridge decks reinforcement materials such asFRP grids or steel grids are used to constrain the cracks andimprove the stiffness of the bridge decks [5 6] With theincreasing demand for daily traffic there are stricter re-quirements for the bridge erection speed long-term reli-ability overload resistance and fatigue resistance

Considering the safety and durability of the bridge andapplying the necessary strengthening can improve thebearing capacity and stiffness of the bridge and extend itsservice life

In general steel bars are corrosion resistant owing to thealkaline concrete protective layer (pHgt 12) however forbridges exposed to harsh conditions the pH of the concretedecreases at a rate of 10 per year [8] and the steel barscorrode easily because of the acidification of the concrete(e corrosion of the steel bars in bridge decks is particularlysevere owing to the thinness of the protective layer and thepermeation of deicing salt on the surface of the steel barsReinforced concrete bridge decks have been damaged todifferent degrees after using for years (ere were approx-imately 600000 bridges in service in the United States in theearly 1990s among which approximately 100000 sufferedserious corrosion problems involving steel bars resulting inlosses of $70 billion (USD) per year [9] (erefore it is ofgreat practical significance and research value to developmethods for reinforcing the damaged bridges and analyze

HindawiAdvances in Materials Science and EngineeringVolume 2020 Article ID 8682163 21 pageshttpsdoiorg10115520208682163

the mechanism and failure modes of the reinforced struc-tures to improve the durability and sustainability of theexisting bridge structures

With the application and development of the traditionalreinforcement technology new building materials are pro-duced and new strengthening methods are developed Usingthe fiber-reinforced polymer (FRP) to strengthen the concretestructures is an ideal method at present(e FRP is a new typeof high-performance material that is composed of a fibermaterial and a matrix material mixed in a certain proportionand compounded via a certain process(e fibers are themainstress materials in the FRP and can be divided into long fibersand short fibers Long fibers are mainly used in FRPs forengineering structures (e fiber plays the roles of stiffeningand strengthening and the resin plays the role of bonding thefiber It can provide reinforcement via the shear force betweenthe FRP sheets and the concrete Recently FRP has beenwidely used as a strengthening material in civil and con-struction engineering structures and repair engineering owingto its high strength light weight corrosion resistance andfatigue resistance [10ndash13]With the rapid development of FRPprocessing and molding technology industrial formingprocesses such as pull-extrusion winding resin transfermolding and vacuum import can produce large standardizedFRP components with stable performance providing thebasic conditions for the wide application of FRP bridgesCurrently the FRPs commonly used in engineering structuresare the carbon fiber-reinforced polymer (CFRP) glass fiber-reinforced polymer (GFRP) basalt fiber-reinforced polymer(BFRP) and aramid fiber-reinforced polymer (AFRP)[14ndash17] In structural engineering the main product forms ofFRP include laminates (sheets and plates) bars cables andgrids [18ndash24] (e most common methods for strengtheningusing FRPs are externally bonded (EB) and near-surfacemounted (NSM) reinforcements [25ndash28]

Some researchers investigated the shear and flexuralperformance of reinforced concrete beams strengthenedwith FRP materials and they obtained some remarkablereinforced effect Hawileh et al [29] studied the effect of

externally bonded CFRP sheets on the shear strength ofshear-deficient reinforced concrete beams as attached to thebeamrsquos soffit (ey indicated that the shear strength ofreinforced concrete beams increased 10ndash70 comparingwith the control specimens (ey also found that the flexurallongitudinal reinforcement ratio played a significant role onthe shear strength of reinforced beams (e effects of theratio of longitudinal reinforcement and angle of applicationof CFRP sheets on the shear capacity of reinforced concretebeams with externally bonded CFRP sheets were investi-gated by (amrin and Zaidir [30] (ey showed that theangle of application of CFRP sheets (45deg and 90deg) had almostno effect on the shear capacity of reinforced beams anddifferent ratios of longitudinal reinforcement resulted indifferent failure modes (ree-sided or completely wrappedapplication of CFRP sheets may be necessary to preventpremature debonding failure for beams with higher values ofthe longitudinal reinforcement ratio (ey also studied theshear strength of reinforced concrete beams with NSM bars[31](e results demonstrated that the strengthened methodcan increase the shear capacity of reinforced beams sig-nificantly In the meanwhile Saqan et al [32] indicated thatboth the strengthening methods of bonded CFRP sheets andNSM bars delayed the yielding of the internal steel rein-forcement and resulted in an increase in the flexural strengthand a decrease in stiffness degradation of the reinforcedconcrete frames Hawileh et al [33] studied the contributionof CFRP laminates on the shear strength of reinforcedbeams (e results demonstrated that the external flexuralCFRP laminates can improve the shear strength of rein-forced members as the vertical sides of reinforced membersare not accessible Moreover using U-wrapped and com-pletely wrapped CFRP sheets were two common wrappingconfigurations to improve the shear capacity of exsitingreinforced concrete structures [34] Some concrete beamscannot strengthen with FRP laminates due to the narrowsoffit To overcome this obstacle Salama et al [35] inves-tigated the feasibility of strengthening reinforced concretebeams in flexure by side-bonded CFRP sheets (ey

2004 8 13

(a) (b)

Figure 1 (e damage of traditional asphalt pavement on a steel deck [7]

2 Advances in Materials Science and Engineering

indicated that the strengthened method of side-bondedCFRP sheets can not only improve the flexural strength butalso increase the shear strength of the reinforced membersIn addition strengthening with FRP bars or using FRPsheets can increase the flexural performance of reinforcedconcrete members [36ndash38]

With the increasing application of FRP strengtheningmaterials FRP materials have played a significant role in themodern construction industry Although the use of FRP forstrengthening concrete structures has made significantprogress few reviews of the strengthening of bridge struc-tures have been published (erefore it was necessary toconduct a broad overview of the literature and the existingstate of development regarding the application of FRPmaterials for strengthening bridge structures (is reviewfocuses on the types of FRP materials strengthening tech-nologies and performance indicators (bearing capacitybonding and ductility factor) from the viewpoint of FRP-reinforced bridge structures (is review is believed to beuseful for researchers and engineers as it provides a deepunderstanding of the strengthening of bridge structuresusing FRP materials

2 Strengthening Materials

FRP materials consist of two basic materials fiber materialsand matrix materials (e fiber materials mainly includecarbon fiber glass fiber basalt fiber and aramid fiber andthe matrix materials consist largely of resins (ese twomaterials are mixed at a certain proportion followed by acomplex process resulting in the formation of a new type ofhigh-performance material an FRP Recently FRPs havebeen widely used in civil engineering particularly forstructural reinforcement owing to its light weight highstrength and corrosion resistance [39ndash44]

21 Types of FRPs

211 CFRP (e CFRP is one of the earliest fiber compositematerials used for bridge reinforcement and is widely used infiber-reinforced composites because of its high tensilestrength and elastic modulus (e main structural forms ofCFRP are sheets bars (strips and rods) and grids (eperformance of CFRP bars in the transverse direction isinferior to that in the longitudinal direction which results inpremature failure in tensile tests [45] (e parameters of theCFRP bars are presented in Table 1 Pultruded CFRP stripsare fabricated with unidirectional carbon fibers embedded ina vinylester resin matrix [42] Information regarding CFRPstrips and laminates is presented in Table 2(e CFRP grid isa new FRP configuration that has been used in the punchingshear resistance of concrete slabs [46] and to reinforce steeldeck plates for enhancing the stiffness [7] Meisamit et al[47] reinforced concrete slabs with CFRP grids and pre-sented a theoretical method for predicting the loading ca-pacity of the reinforced slabs by considering the real rupturemode In [48] differences were observed between CFRPgrids and steel reinforcements as strengthening materials forconcrete slabs because of the linear elasticity of the CFRP

grids In comparison with the steel reinforcements theelastic modulus fatigue strength and creep resistance of theCFRP were higher and its expansion coefficient in the di-rection was lower [41 49 50] A comparison of the me-chanical properties and comprehensive performance indicesindicated that the CFRP is more promising and advanta-geous than the steel reinforcements CFRP has a highstrength and elastic modulus and good corrosion resistanceHowever carbon fibers are expensive owing to the lack ofkey technologies for raw silk production [51] Additionallycomponents strengthened with CFRP are prone to brittlefailure particularly at high temperatures and the tensilestrength of the carbon fibers decreases significantly [52](eelastic modulus and tensile strength of CFRP at 250degC werereduced by about 28 and 42 respectively as compared toroom temperature [53] Moreover CFRP exhibits electricalconductivity thus it cannot be used in applications re-quiring insulation [54 55]

212 GFRP GFRP was widely applied in civil engineeringowing to its smooth surface excellent permeability resis-tance corrosion resistance (to acid alkali seawater andfresh water) and high cost-effective performance [58]GFRP is a composite engineering material with the rein-forced material of glass fiber and the polymer matrix ofsynthetic resin Owing to its low cost and good corrosionresistance GFRP is often used as a replacement for steel torepair damaged concrete structures [59 60] Researchershave proven that steel is an isotropic material and it is veryprone to electrochemical corrosion and yield in contrastGFRP is an anisotropic material with excellent tensionperformance [61ndash64] Glass fiber is formed by melting glassand drawing and it is inexpensive Moreover comparedwith using steel the use of GFRP for strengthening concretebridges at the characterization level of the cradle-to-gravescenario can reduce global warming photochemical oxidantcreation acidification and eutrophication by 25 15 5and 50 respectively [65] However the elastic modulus ofGFRP is low the creep is large and the durability is poorAdditionally GFRP is highly sensitive to alkaline environ-mental conditions [51] (e properties of GFRP are pre-sented in Table 3

213 BFRP Basalt fiber is an inorganic fiber materialderived from the raw material of the glassy basalt mineformed by volcanic eruption which is stretched by aspinneret after being crushed and fused at a high tem-perature (1400degC) [67 68] (e color of basalt fiber is darkbrown similar to carbon fiber Basalt fiber has highstrength good modulus excellent stability high tem-perature resistance and chemical resistance additionallyit is easily fabricated nontoxic nonhazardous eco-friendly and inexpensive [69ndash74] Basalt fiber is six timesless expensive than carbon fiber because of the availabilityof the raw materials and the simple manufacturing process[71] BFRP shows stable mechanical properties under ahigh-temperature environment In experimental strengthtests of basalt fibers carbon fibers and glass fibers at 100

Advances in Materials Science and Engineering 3

200 400 600 and 1200degC the strengths of all three fibersdecreased above 200degC however while the strengths ofthe carbon fiber and glass fiber decreased significantly thestrength retention rate of the basalt fiber was gt90 at600degC [75] Moreover as the temperature increased from100 to 250degC the tensile strength of the basalt fiber in-creased by 30 but that of the glass fiber decreased by23 In 70degC hot water the strength of the basalt fiber wasmaintained for 1200 h but the glass fiber lost strengthafter lt200 h [76] Although the tensile strength and elasticmodulus of basalt fiber are lower than those of carbonfiber basalt fiber has advantages with regard to theductility cost corrosion resistance and high-temperatureresistance Sim et al [75] examined the four-point loadingfailure of 10 basalt fiber-reinforced concrete beams (eirexperiments revealed that the yielding strength and ul-timate strength increased by 15 and 0 with one layer ofbasalt fiber sheet 26 and 27 with two layers and 16and 29 with three layers respectively

Basalt fiber can be used as reinforcement to producevarious forms of basalt composite materials Compared withother fiber materials basalt fiber has many advantages andspecial properties

(1) Basalt fiber is manufactured using natural rock as araw material and is a pure natural inorganic materialwith excellent mechanical properties ideal durabil-ity and good adaptability to various environments

(2) With rich raw materials basalt fiber has a low costBFRP is expected to approach the level of GFRP atthe various properties in future which can breakthrough the price bottleneck in FRP application

(3) Basalt fiber is particularly suitable for seismicstructures with a high ultimate strain and goodductility

(4) Basalt fiber has a good fatigue resistance strongadhesion with resin and excellent compatibility withmetal plastic and carbon fiber

However basalt fiber also has shortcomings such aspoor shear performance brittleness and a low elasticmodulus

214 AFRP AFRP is a high-strength aromatic polyamidesynthetic organic fiber with light weight high strength andgood corrosion and heat resistance [77ndash79] AFRP sheets are

Table 2 Physical properties of CFRP strips and laminates

Types Width(mm)

Length(mm)

(ickness(mm)

Tensile strength(MPa)

Elastic modulus(GPa)

Ultimatestrain ()

Decompositiontemperature (degC)

CFRP sheet[56] mdash mdash 012 4100 231 17 mdash

CFRP strips[42] 10 mdash 14 2850 168 16 380

CFRP plate[57] 20 90ndash180 2 4100 256 mdash mdash

Table 3 Properties of GFRP

Types Nominal diameter(mm)

(ickness(mm)

Width(mm)


Tensile modulus(GPa)

Fracturestrain ()

GFRP bars [66]8 mdash mdash 1175plusmn 16 49plusmn 3 25plusmn 0410 mdash mdash 1241plusmn 67 53plusmn 3 23plusmn 0312 mdash mdash 1166plusmn 60 53plusmn 5 24plusmn 02

GFRP bars [16] 12 mdash mdash 1113 623 1816 mdash mdash 1102 612 18

GFRP plate with a transverse surfacemat [17] mdash 4 50 516 33 160

GFRP plate without a transversesurface mat [17] mdash 4 50 722 51 142

Table 1 Physical properties of CFRP bars [45]


Nominal area(mm2)

Guaranteed tensile strength(MPa)

Max tensile load(kN)

Modulus of elasticity(GPa)

Ultimatestrain ()

CFRPbars

6 3167 2241 71 124 18110 7126 2172 154 124 17313 1267 2068 262 124 167


made of aramid fibers arranged in one or two directions andthey are light soft durable insulating and corrosion re-sistant Compared with GFRP AFRP has higher strengthhigher elastic modulus better heat resistance and lowerdensity [80] (e tensile strength of AFRP is nearly five andtwo times higher than that of steel and GFRP respectively[81] Additionally compared with CFRP AFRP is easier tofabricate has a higher alkaline resistance and is less ex-pensive [82] However AFRP has limited applicability tocivil engineering and building construction owing to its lowcompressive strength and high tensile strength [80]

215 Hybrid Fiber-Reinforced Polymer (HFRP) Hybrid fi-ber is a composite material with more than two types offibers reinforcing the same matrix which can improve thecomprehensive mechanical properties of the single fibermaterial increase the fiber utilization rate and reduce thecost [67] Polyolefin fiber is the most popular synthetic fiberused for strengthening concrete members and is fabricatedwith organic polymers polymerized by olefins via chaingrowth [83] (ere are advantages of suppressing the de-velopment of shrinkage cracks preventing the formation ofinternal cracks increasing the ductility and reducing thesegregation balling and bleeding of concrete [84] Hybridcomposites with carbon fiber and polyethylene fiber wereinvestigated by Park and Jang [41] (ey used the open leakymold method to fabricate the hybrid fiber and found that theposition of the reinforcing fiber significantly affected themechanical properties of the hybrid fiber (e HFRPexhibited the highest flexural strength with the carbon fiberat the outermost layer owing to the maximum magnitudesof the compressive and tensile stress at the outermost layer(e hybrid fiber sheet was fabricated vertically with glass andaramid fibers and the glass fiber was the main stress-bearingfiber Eswari [85] proved that the strength crack propaga-tion and ductility of HFRP were better than those of thesingle fibers (e hybrid fiber exhibited excellent perfor-mance and reduced the costs [86]

22 Products of FRP

221 FRP Sheets FRP sheets are the most widely used formin the building reinforcement (ey are fabricated withlong continuous fibers and are typically used for the re-inforcement of structural members affixed to the surface ofthe concrete members after being impregnated with resinFRP sheets generally only bear unidirectional stretching(e width of FRP sheets can be 20 30 50 or even 100 cmthe length is between 50 and 100m which is sufficient toavoid lapping (e surrounding environments of FRPsheets determine their properties (e effects of fresh waterseawater a negative temperature (minus155degC) and freeze-thaw cycling on the flexural performance were examinedand the degree of degradation decreased in the followingorder negative temperature (minus155degC) gt freeze-thawcycling gt fresh water gt seawater [87] Moreover Ghar-achorlou and Ramezanianpour [88] reported that a largernumber of FRP layers resulted in better durability as the

reinforced concrete members with FRP sheets were ex-posed to the saline solution In the saline solution thedegradation of the properties mainly depended on thehumidity meanwhile the salt crystals increased the degreeof degradation owing to the crack expansion [89] (emechanical performance of GFRP sheets decreased as thetemperature increased from 35 to 65degC in a NaCl solution[90] FRP sheets are commonly applied for strengtheningbeams slabs and columns (ey are easily bonded with thesurfaces of concrete structures which can increase theflexural strength and shear strength of the concretemembers

222 FRP Bars FRP bars are fabricated via a unidirectionalpultrusion molding process via the mixing of unidirectionallong fibers and resin (e surface of the FRP bar can betreated as a ribbed bar to enhance the bonding capacity incontrast to that of a round bar [91] (e FRP cable is a wire-like FRP product formed via unidirectional weaving ofcontinuous long fibers followed by solidification with a smallamount of resin or without resin FRP bars and cables canreplace steel bars and prestressed bars in reinforced concretestructures and can also be used in long-span cable supportstructures tensioned structures and suspended cablestructures

CFRP bars are composed of carbon fibers and a resinmatrix thus carbon fibers play an important role instrengthening and resin is mainly used to bond the fibers(e volume content of CFRP bars is between 60 and65 and as the fiber content increases the strength in-creases but extrusion molding becomes more difficult(e cross sections of CFRP bars are generally round andthe shapes of the surface mainly include smooth nickedand wrapping Different surface treatment methods resultin different bonding performances between the CFRP barsand concrete (e diameter of most CFRP bars is5ndash12mm and the mechanical properties of FRP bars andprestressing steel are presented in Table 4 Examples of theGFRP and BFRP bars are presented in Figure 2

Compared with steel strands CFRP bars generally havethe following characteristics [93ndash95]

(1) (e longitudinal tensile strength and compressivestrength of CFRP bars are higher but the transversestrengths are lower CFRP bars are typically brittleand exhibit obvious anisotropy and there is noobvious yield stage before the tensile strength isreached Additionally the ultimate strain is small

(2) (e low elastic modulus of CFRP bars results inexcessive deflection and wide cracks of concretestructures with CFRP bars which can be avoided byapplying prestress

(3) (e density of CFRP bars is only approximately 14of that of the steel strands which is beneficial forreducing the weight of the structure and conve-nient for installation

(4) (e coefficient of thermal expansion of CFRP bars issignificantly different from that of concrete


Additionally the axial coefficient of thermal ex-pansion is small which is beneficial for adaptation tothe climate

(5) CFRP bars can be used in corrosive environments fora long time because of their excellent corrosionresistance moreover they can reduce the mainte-nance cost

(6) Compared with steel CFRP bars can reduce theeffects of electromagnetic fields on instruments

inside the structure owing to their excellent anti-magnetic performance

(7) (e fatigue resistance of CFRP bars is better than thatof steel and CFRP bars can satisfy the fatigue re-quirements of building structures

223 FRP Grids FRP grids (Figure 3) can be formed byweaving long fiber bundles perpendicular to each other atcertain intervals and then solidified with resin For the long

Table 4 (e mechanical properties of FRP bars and prestressing steel [92]

AFRP CFRP GFRP Prestressing steelFiber volume ratio 065 065 055 mdashDensity (gcm3) 128 153 21 785Longitudinal tensile strength (GPa) 125ndash14 225ndash255 108 186Transverse tensile strength (MPa) 30 57 39 1860Longitudinal E-modulus (GPa) 65ndash70 142ndash150 39 210Transverse E-modulus (GPa) 55 57 86 210In-plane shear strength (MPa) 49 71 89 mdashIn-plane shear modulus (GPa) 22 72 38 721Major Poissonrsquos ratio 034ndash06 027 028 03Minor Poissonrsquos ratio 002 002 006 03Bond strength (MPa) 10ndash13 4ndash20 mdash 66ndash71Maximum longitudinal strain () 20ndash37 13ndash15 28 40Maximum transverse strain () mdash 06 05 40Longitudinal compressive strength (MPa) 335 1440 620 1860Transverse compressive strength (MPa) 158 228 128 1860Longitudinal thermal expansion coefficient (times10minus6middot1degC) minus2 minus09 7 117Transverse thermal expansion coefficient (times10minus6middot1degC) 60 minus27 21 117

(a) (b)

Figure 2 FRP bars [93] (a) GFRP bars (b) BFRP bars


continuous fiber carbon fiber glass fiber basalt fiber andaramid fiber are often used FRP grids can replace the steelmesh and an FRP cage can replace the steel cage

According to the products on the market FRP grids arecategorized as follows

(1) According to their shape they can be classified assingle reinforced composite-type or whole-type Inthe former case FRP bars form a grid via cross lapjoints In the latter case the fibers are directly so-lidified as fiber bundles and the resin is laid into amesh

(2) According to the types of reinforced fibers FRP gridsare divided into BFRP grids CFRP grids GFRPgrids and AFRP grids

(3) According to the mesh shape they can be classifiedinto bidirectional square grids and tridirectionalequilateral triangle grids

(4) According to the stress direction there are isotropicstrengths and different strengths in different direc-tions (ie the fiber contents in two or three direc-tions are different)

(5) According to their appearance FRP grids are clas-sified as embossed type or smooth type

(e main control parameters of FRP grids include themesh size (50times 50mm2 100times100mm2 150times150mm250times100mm2 and 100times150mm2) mesh width (05 1 15and 2m) and mesh thickness (05 1 15 2 3 4 and 5mm)(e mechanical properties of FRP materials are presented inTable 5

3 FRP Strengthening Methods forBridge Structures

Concrete bridges which include reinforced concrete bridgesand prestressed concrete bridges are widely used worldwideAt present most of these bridges are subject to multipletypes of damage thus the design grade of the originalbridges does not satisfy the current requirements and re-inforcement is needed Among the FRP strengtheningmethods the EB FRP technique (bonding CFRP to the

surface of the concrete) was first proposed [97] Recentlywith the development of the strengthening technique thenear-surface mounted (NSM) FRP method was proposedwhich involves bonding the FRP barsstripsrods in theprecutting grooves on the surface of the concrete cover Incomparison with the EB FRP technique NSM FRP exhibits ahigher strengthening efficiency and better protection againstenvironmental agents vandalism impact loads and expo-sure to high temperatures [98 99] (e details of the re-inforcement methods for concrete bridges are presented inthe following sections

31 Externally Bounded Steel Plate (e reinforced methodof the externally bounded steel plate involves attaching asteel plate to the tensile part of the member with a specialbuilding structure adhesive thus the steel plate and theoriginal member are combined forming a single structure(ey bear the load together increasing the bearing capacityof the members (is method has the advantage of a shortconstruction period moreover it consumes little spacehardly alters the shapes of the members and significantlyimproves the bearing capacities of the members and theperformance in the normal use stage However it also hasdisadvantages for example it can increase the weight of thestructure and the steel plate can corrode easily

In the past the common reinforcement method forbridge decks has involved applying EB steel plates or re-inforcement at the bottom of the bridge decks (e EB steelplate reinforcement technology was first used in SouthAfrica and France [100] Subsequently studies on suchreinforcement methods were performed revealing that theconcrete structure strengthened with steel plates was proneto debonding failure because of the stress concentration atthe ends of the reinforced steel plates [101 102] In 1988Jones et al [103] improved the anchorage measures for theend of the steel plate to prevent debonding failure More-over another reinforcement method was proposed thick-ening the section of the decks for reinforcement howeverthis method resulted in a large construction area addi-tionally it is difficult to reinforce the bridge decks Steel isused in these two reinforcement methods which is not onlyheavy but also has poor corrosion resistance (ereforethere are still obvious defects and low sustainability inpractical application [104]

32 Externally Bonded FRP Sheets At the beginning of theapplication of FRP in reinforcement the common rein-forcement method is to bond the FRP sheets or otherlaminates on the tensile area of the concrete beam providinga passive reinforcement Although this strengtheningmethod can improve the flexural bearing capacity of con-crete beams and reduce the development of deflection andcracks there is a strong stress hysteresis reaction whichresults in a poor reinforcement effect (is is because theperformance of the reinforcement members mainly dependson the original number of reinforcements in the concretebeams thus the high tensile strength of the FRP sheets is notfully exploited [56 105 106] Moreover the most effective

Figure 3 Overview of FRP grids [48]


way to strengthen the concrete columns with FRP sheets orother laminates is to confirm the shear strength of concretemembers according to the deformation constraint of thestructure However the reinforcement effect depends on theshape of the concrete Researchers [107ndash109] reported thatthe shear strength and deformation capacity of rectangularconcrete columns can be improved via bonding with FRPsheets but there was the upper limit of the compressivecapacity If the rectangular column is treated with a certainradian the compressive bearing capacity can be significantlyimproved Bonding FRP materials has the fatal problem thatthe strength cannot be fully used and there is a stresshysteresis reaction (e key to solving this problem is ap-plying prestress to FRP materials (e reinforcement ofprestressed FRP sheets can effectively solve the problem ofenhancing the time efficiency which not only reduces theexisting load effect of the reinforcement members but alsoreduces the existing deformation and the widths of cracks inthe reinforcement members After the reinforcement theprestressed FRP materials and the concrete members aresubjected to the force simultaneously which can preventdeformation the development of existing cracks and thegeneration of new cracks However anchors that have ex-cellent performance are practically applicable and fullyexploit the tensile strength of the FRP sheets are necessary toachieve reliable prestressed FRP reinforcement

However the significant disadvantage of reinforcedmembers with FRP laminates is the debonding failure be-tween the FRP and the concrete which can suppress thestrengthening effect for EB FRP laminates [110 111]

(e bonding interface between FRP materials andconcrete members is the weak links in the stress process andthe failure modes are brittle failure and debonding failure(us the debonding failure can be divided into four types[112ndash114] (1) the stress concentration at the end of the bondinterface resulting in debonding (2) the shear cracks in thereinforced members resulting in debonding (3) the flexuralcracks that extend to the reinforced members resulting indebonding and (4) the layer debonding along the originalreinforcement of the reinforced members

Furthermore in the strengthening method calledldquogroovingrdquo the EB reinforcement is applied onin grooves toprevent debonding failure and enhance the ultimate bearingcapacity [56] Reinforced concrete members prepared usingdifferent strengthening methods are shown in Figure 4 Forstrengthening with one layer of an FRP sheet the effects ofthe failure loads and displacements on the EB reinforcementon grooves were similar to those on the EB reinforcement ingrooves For strengthening with two or three layers of FRP

sheets the technique of EB reinforcement in grooves led tohigher failure loads and displacements than EB reinforce-ment on grooves

33 Strengthening with FRP Grids FRP grids have longi-tudinal and transverse fiber bars and both have a certainstrength and stiffness Fiber bars in both the longitudinal andtransverse directions are subjected to tensile forces whichcan act as constraints in both directions (e strengtheningmethod for the FRP grid involves fixing the FRP grid on theconcrete surface with anchors and then applying a sealingtreatment FRP grids can be used to strengthen the structuresin special environments and exhibit good applicationprospects FRP grids are always used together with polymermortar [20 96] First FRP grids are fixed by a mechanicalanchorage then a layer of polymer mortar is added outsideas a protection layer which can improve the uniformity ofthe force transmission as well as the debonding failureresistance durability and fire resistance (e installationprocedures for the cast-in-place method are presented inFigure 5

(e strengthening technology for FRP grids has thefollowing characteristics [20 96 115ndash117]

(1) FRP grids are light and thin (ey are significantlylighter than steel bars and the section of the FRP gridis thinner than that of the steel bar Moreover theFRP grid is easy to transport and apply withoutheavy-lifting equipment

(2) (ematerials of the FRP grids are composed of high-strength fiber and resin with good corrosion resis-tance therefore the FRP grid has excellent durabilityin cold areas and coastal areas

(3) (e continuous reinforcing fibers are distributed intwo directions (e bond-slip resistance is good anddebonding failure between the reinforcing materialand the concrete does not easily occur owing to themechanical anchoring and the polymer mortarWhen FRP grid is used in the bending reinforce-ment it can not only improve the bearing capacitybut also enhance the stiffness and cracking resistanceof the reinforced member

(4) With the protection of polymer mortar the FRP gridimproves the impact resistance fire resistance anddurability (erefore FRP grids can be used to re-place steel bars in some new buildings with specialrequirements for anticorrosion antimagnetic anti-seismic and antiexplosion materials

Table 5 Mechanical properties of materials [96]

Material Yield stress (MPa) Yield strain () Ultimate strength (MPa) Rupture strain () Elastic modulus (GPa)Tensile steel bar 467 0242 628 mdash 193Compressive steel bar 467 0242 628 mdash 193Stirrup 453 0227 467 mdash 200CFRP grid mdash mdash 1400 140 100BFRP grid mdash mdash 1760 220 80


Additionally in comparison with the reinforcementmethod of FRP sheets FRP grids can improve the stiffness ofthe members and be less prone to debonding failure thusthey are more suitable for reinforcement in harsh envi-ronments Because FRP sheets are soft and their adhesionrelies on the resin there are limitations in reinforcing theconcrete structures When the interface roughness of thereinforced structure is inadequate the properties are sig-nificantly degraded Furthermore FRP sheets cannot beapplied in humid environments or underwater (ereforethe overall strengthening effect of FRP grids is better thanthat of FRP sheets

(e Niiborigawa Bridge in Japan had long sufferederosion due to salt and is a representative example of theremoval of the deteriorating concrete and the use of CFRPgrids and polymer mortar for strengthening [118] Duringthe eight-year natural aging process the CFRP grids in theconcrete beam maintained excellent properties includingthe strength stiffness and corrosion resistance Zhang et al[48] performed static and cyclic loading tests of three one-way concrete slabs strengthened by CFRP grids and steelbars (ey found that the reinforcement ratio significantly

affected the flexural stiffness because the stiffness of theconcrete slab strengthened by CFRP grids decreased sig-nificantly after the crack initiation in comparison with thatof the concrete slab strengthened by steel bars Brunton et al[119] studied the punching shear capacity of a full-scaleconcrete bridge deck strengthened by pultruded FRP gridsand found that the Jacobson equation could predict thepunching shear capacity of concrete decks with or withoutedge restraint EB grids are effective for enhancing thebearing capacities and deformation capacities of concretemembers Moreover the effects of the number of FRP gridlayers type of FRP grids (CFRP GFRP or BFRP) type ofbonding agent (inorganic material or epoxy resin) andcompressive stress level on the mechanical performance ofreinforced members are major parameters [120] Undersufficient anchoring the flexural capacities and deform-abilities of members strengthened by FRP grids increased byfactors of gt4 and gt13 respectively Strengthening concretebridge decks with FRP grids solves the problems of fatigueand corrosion additionally the ultimate load is higher thanthat in the case of strengthening with steel grids [121ndash123]Moreover fiber-reinforced concrete can solve the problem

(a) (b)

(c)

Figure 4 Specimens strengthened with (a) conventional surface preparation method (b) externally bonded reinforcement on groovestechnique and (c) externally bonded reinforcement in grooves technique [56]

(a) (b)

Figure 5 Installation procedures for the cast-in-place method [96]


of brittle failure of concrete plates reinforced with FRP gridsYang et al [96] investigated the effects of the ratio of theshear span to the effective depth matrix type FRP grid typeand installation method on the shear capacity of thestrengthened beam (ey found that the reinforcement withFRP grids enhanced the shear capacity of the reinforcedbeam particularly with the application of the prefabricationmethod Additionally they reported that in comparisonwith CFRP grids and the cast-in-place method the beamsstrengthened with BFRP grids in the prefabrication methodwere more suitable for the reinforced beam

34 StrengtheningwithPrestressingFRPBars In the externalprestressed structure the prestressed bars are arrangedoutside the section and the prestress is applied to thestructure only by the anchorage area and steering block(e system comprises an externally prestressed pipe paste(anticorrosive grease or cement) an anchorage systemand a steering block [124ndash127] External prestressingreinforcement technology can improve the internal forceand deformation of the control section and enhance thebearing capacity cracking resistance and deformationresistance of the bridge because the internal force gen-erated by prestressing on the structure offsets parts of theinternal force generated by the loads

(e external prestressing technique is particularlysuitable for the reinforcement of the concrete bridge in thefollowing situations

(1) (e bearing capacity of the structures decreasesowing to the corrosion of steel

(2) (e load grade of the bridge must be improved(3) (e cracking of the beam and the fatigue stress of the

reinforcement should be controlled in a reasonablerange

(e external prestress on the strengthening of thebridge can result in the distribution of the stress whichcan enhance the performance of the structure undernormal service loads Additionally it is suitable forstrengthening various bridges because the arrangement ofthe external prestressed tendons is flexible (e externalprestressing technique has broad application prospects inbridge reinforcement (e external prestressing method isone of the important aspects of the posttensioned pre-stressing system and has the following advantages forreinforcement

(1) It is convenient to check repair and replace theexternal prestressed tendons

(2) (e arrangement of the prestressed tendons issimple which simplifies the operation of the post-tensioning method

(3) (e prestressing tendons have no contact with theconcrete member except at the anchorage area andsteering block which reduces the friction loss

(4) It can improve the flexural and shear bearingcapacity

(5) (e stress generated by the load is distributed uni-formly along the length direction with small varia-tion range which is beneficial to the bearing capacityand fatigue load

(e first prestressed concrete bridge using CFRP bars inthe world was built in Japan in 1993 Japan was a pioneeringcountry in the use of prestressed FRP bars CFRP bars wereused as suspension cables to build concrete bridges inSwitzerland Denmark the United Kingdom and Canada[128ndash130] (e external prestressing technology of CFRPbars can be applied to new bridge structures reinforce-ment and maintenance operations of bridges owing to theexcellent corrosion resistance Horvatits and Kollegger[131] successfully strengthened a highway concrete bridgewith a new external prestressed CFRP system Nordin andTaljsten [132] strengthened and rehabilitated existingconcrete structures with CFRP tendons(eir objective wasto evaluate the bearing capacity and service life of existingrailway bridges when the existing load capacity increasedby 25 and the train speed increased to 350 kmh How-ever the desired effect was not achieved owing to theanchorage Matta et al [133] controlled the vertical de-flection of a bridge with a reinforcement of externalposttensioned CFRP tendons (the CFRP bar with a di-ameter of 127mm was arranged under the beam) Mac-dougall et al [134] successfully replaced corrodedposttensioned unbonded prestressed steel tendons withCFRP tendons via the posttensioned method in a parkinggarage in Toronto El-Hacha and Elbadry [24] investigatedthe effects of the span-to-depth ratio partial prestressingratio and reinforcing index on 12 concrete beams withstrengthening external prestressed CFRP tendons (eyreported that the flexural capacity of the strengthened beamwas 70 higher than that of the unreinforced beamMoreover they obtained the formula for the stress in-crement of the CFRP tendons according to thedeformation

At present the anchorage methods for external pre-stressing tendons mainly include broadening the crosssection of the beam end adding a concrete tooth plate andsteel plate anchorage (e former two methods are mostlyapplied to newly built structures and the latter method is themost common technique for external prestressed rein-forcement owing to its advantages of light weight andconvenient construction

35 Near-Surface Mounted FRP NSM FRP is an improvedversion of the traditional EB FRP method [37] NSM FRPreinforcement involves placing FRP bars or laminates intoprecut grooves on the surface of the concrete members withthe corresponding binder (e procedure of NSM FRP re-inforcement is as follows (1) forming the grooves (2)cleaning the grooves (3) half-filling the grooves with thefilling material followed by insertion of the FRP bars and(4) filling the groove with the filling material to the surfacelevel as shown in Figure 6

In comparison with the traditional EB FRP method theNSM FRP method can significantly improve the efficiency


and utilization ratio [135 136] additionally it has significantadvantages for the practical applications of strengtheningbridge structures

(1) NSM FRP enhances the bonding performance be-tween the FRP materials and concrete and is lessprone than EB FRP to debonding failure

(2) NSM FRP increases the bonding area between theFRPmaterials and concrete improving the punchingshearing capacity of the bridge structure [137 138]

(3) Improving the bonding performance between theFRP and concrete can increase the utilization rate ofFRP materials and the ductility of the bridgestructure

(4) FRP bars can be easily anchored on the adjacentcomponents [137]

In 1949 Asplund [139] strengthened a bridge by forminggrooves on the surface of the members however bondingfailure easily occurred owing to the use of cement paste asthe binder and steel bars as the reinforcement materialswhich hindered the further development of this technologyWith the development of new binders and the application ofFRP materials in the construction the NSM FRP techniquehas attracted the attention of researchers Casadei et al [140]repaired a damaged concrete bridge with several soffit slablongitudinal cracks using EB FRP laminates and NSM FRP

bars as shown in Figures 7 and 8 Static load tests and finite-element analysis revealed that both reinforcement tech-niques were effective for strengthening the concrete bridgeAlkhrdaji et al [141] performed the same reinforcement testson a decommissioned and to-be-demolished bridge (eyreported that both EB FRP sheets and NSM FRP rods re-duced the deflections and increased the ultimate load ca-pacity even the latter had a higher capacity and betterbonding performance Moreover the different reinforce-ment methods led to different failure modes When thebridge deck was strengthened with EB FRP sheets the failuremode was the rupture and peeling of FRP sheets when thebridge deck was reinforced with NSM FRP rods the ruptureof FRP rods was the main failure mode

(e bonding performance between the FRP and concretesignificantly affects the strengthening effect of NSM FRPbars Many researchers [135 136 142 143] have investigatedthe bonding performance between FRP and concrete viadifferent test methods (mainly the direct pull-out methodand the bending beam method) Among the various testmethods the direct pull-out method has a direct forcetransmission path and is easy to operate owing to the smallvolume of the specimens but the requirement of thespecimen molding is very strict because slightly eccentricloading significantly affects the results (e bending beammethod can solve the problem of vertical adjustment of theloading but the specimen volume is large the force

(1)

(2) (3) (4)

Figure 6 (e procedure of NSM FRP [37]


transmission is complex and displacement control loadingcannot be used Additionally many factors affect thebonding performance between the FRP and concrete in-cluding the concrete strength the depth and spacing of thegrooves on the surface of the concrete members the bondlength of the FRP the types of binders and the environ-mental conditions

In addition to the bonding performance the flexural andshear properties of concrete structures reinforced with NSMFRP bars have been investigated by many researchersworldwide [21 144ndash149] NSM FRP can significantly im-prove the flexural performance of reinforced concretemembers and the failure modes of flexural reinforcementmainly include concrete failure in the compression zoneFRP fracture debonding failure between the concrete andthe end of the FRP and debonding failure caused by themain crack at the midspan Zhang and Teng [150] developeda bond-slip relationship model that accurately simulated the

debonding failure between the concrete and the end of theFRP the model was verified using experimental results

Michael et al [151] conducted an experimental programon a unidirectional concrete slab for the deck analysis model(ey found that the effect of the resin binder on the en-hancement of the bearing capacity was stronger than that ofcement as a binder and steel bars as embedded reinforce-ment was better for constraint member cracking than FRPbars Similar studies were performed by Hosseini et al [152]who applied different prestress levels to NSM CFRP lami-nates in reinforced concrete slabs (e experimental resultsindicated that the bearing capacity at the serviceability andultimate limit states increased significantly as the prestressincreased (e effects of the FRP type cross-sectional shapesurface treatment method and prestress level on the flexuralperformance of bridge decks strengthened with NSM FRP inthe negative-bending moment regions were investigated[153] (e results indicated that the NSM FRP method was

(a) (b)

Figure 7 Martin Spring Bridge (a) and its soffit slab longitudinal crack (b) [140]

(a) (b)

Figure 8 Externally bonded FRP laminates (a) and NSM FRP bars (b) [140]


beneficial for increasing the yield strength and ultimatestrength of the reinforced concrete slab Martin et al [143]reported that compressive membrane action can enhancethe bearing capacity of concrete slabs strengthened withNSM FRP(erefore it is necessary to consider the effects ofthe panel boundary support conditions on the flexuralperformance of bridge decks strengthened with NSM FRPRegarding the theoretical model analysis of the strength ofconcrete bridge decks strengthened with NSM FRP calcu-lation methods for the flexural and shear capacity should beestablished considering the compressive membrane action[153]

4 Properties of the Reinforced Members

41 Flexural Performance Bridge elements may be con-tinuously subjected to bending action thus the flexuralstrength of the structural members must be enhancedDifferent reinforcement methods can result in differentdegrees of enhancement of the flexural performance of thestrengthened members (e common reinforced methodsare EB FRP laminates externally prestressed FRP tendonsand NSM FRP bars [23 27 148 154ndash159]

Compared with unreinforced members the loadingcapacity of the concrete beams strengthened with FRP CFRPsheets was higher but the ductility was lower [112] and themain failure mode was peeling failure of the concrete covernear the FRP sheets Choobbor et al [155] applied CFRPBFRP composite sheets to nine reinforced concrete beamsand investigated the flexural performance of the beams(eyfound that the ultimate capacity of the reinforced membersincreased by 66ndash75 compared with that of the unrein-forced beam Moreover they established a precise finite-element model for predicting the ultimate load-carryingcapacity and the deflections (the deviation was lt12)Additionally researchers have studied new FRP reinforce-ment materials and found that the bearing capacity ofmembers strengthened with the new FRP (natural FRP) wasenhanced by 41 (larger than the enhancement forstrengthening with CFRP) [160] (e strengthening effect ofFRP plates on the reinforcement of concrete structures isbetter than that of FRP sheets owing to the large cross-sectional areas the high stiffness and the convenience of theconstruction [11](e effect of the thickness of FRP plates onthe flexural performance of a concrete beam strengthenedwith the FRP plates was investigated [161] Compared withan unreinforced beam thicker FRP plates resulted in ahigher ultimate load the largest increment was 1122Although the tensile strength and elastic modulus of FRPplates are lower than those of steel plates the increase in theultimate lateral load-carrying capacity of the members withEB FRP plates is approximately equal to that for memberswith EB steel plates

Together with the results of the reinforcement experi-ment the researchers provided a calculation method for thecracking moment crack width and deflection of reinforcedmembers with prestressed CFRP plates [11] (e crackmoment and ultimate moment increased by 121 and 103respectively for reinforced slabs strengthened with external

prestressed FRP tendons [162] In the external prestressingsystem the anchoring technology was the key forstrengthening the one-way concrete slab with externallyprestressed tendons An innovative reliable and efficientanchoring technology ensured the prestressing level andrecovered the long-term prestressing losses To enhance thebonding performance between the FRP materials and theconcrete the NSM FRP method was introduced Comparedwith other types of FRP CFRP was considered to be themostsuitable for the NSM FRP strengthening technique owing toits high stiffness and strength (e dosage of FRP materialsthe steel reinforcement ratio and the failure modes are thekey parameters for the effectiveness of the strengthening[163 164] Moreover because the ratio of the perimeter tothe cross-sectional area was higher for FRP strips than forFRP round bars the bond efficiency of the NSM FRP stripswas better than that of the NSM FRP round bars for thestrengthening of concrete members via the NSM FRPtechnique [163] Many researchers have investigated theflexural performance of the concrete structures (beams orslabs) strengthened with NSM FRP materials (laminatesbars and strips) [26 146ndash148 165] (ey found that theNSM FRP technique can enhance the load-carrying capacityof the strengthened members and maintain a correspondinglevel of moment redistribution However the NSM CFRPstrip method enhanced the flexural stiffness of thestrengthened concrete beam after the cracking stage insteadof at the stage of elasticity [148]

42 Bonding Performance Concrete members reinforcedwith FRP sheets or plates are attracting increasing attentionfrom engineers and researchers for construction applicationsowing to their excellent advantages eg their corrosion re-sistance and light weight (ere are numerous bond-strengthmodels for EB FRP sheet applications [113 114 166ndash171]Bonding is the key for the stress transfer between the FRPmaterials and the concrete substrate [172] Many designcriteria limit the strain of the FRP sheets to prevent midspandebonding failure and the interaction of the concrete pro-tective layer FRP sheets and steel bars results in midspandebonding failure [173] (e effects of the concrete strengththe quality of the concrete surface the thickness of the glueline and the characteristics of FRP sheets (types stiffnessbond length width and bond layers) on the bond strength ofconcrete members strengthened with FRP materials havebeen investigated [174ndash177] Although the FRP sheets coveredthe entire tension area of the reinforced member they did notprevent debonding failure [112]

With the advancement of FRP applications researchers[178 179] have developed techniques for preventingdebonding failure using steel bolting and bonded FRPU-shaped channels or jackets at the end of the beam or atintermediate locations However the bolting method candamage the FRP materials during the fabrication process[172] One of the main weaknesses of the EB FRP laminatemethod is the premature debonding of the FRP materialswhich results in the low utilization of the materials [38]Researchers demonstrated that the method of EB


reinforcement on grooves can successfully postpone thedebonding in applications of flat slabs Ceci et al [180]studied the debonding failure mechanism of a concretebeam strengthened with FRP sheets and predicted thedebonding failure mode

(e ultimate bond strength was determined using themodel of Chen and Teng as follows

PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)

where fc represents the compressive strength of the concretebf represents the width of the FRP sheets Le represents theeffective bond length bc represents the width of the rein-forced structure Ef represents the elastic modulus of the FRPsheets and tf represents the thickness of the FRP sheets

To adopt the method of EB reinforcement on grooves acoefficient considering the effect of grooving was added tothe model of Chen and Teng as follows

PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873

minus 08881 minus 0006h

2g + 01hg + 004bg1113872 1113873

(2)

where hg represents the height of the grooves and bg rep-resents the width of the grooves

43 Ductility (e ductility is a necessary factor forevaluating the ability of the members to withstand plasticdeformation before ultimate failure (e evaluationmethod for the ductility involves calculating the ductilitycoefficient which can be represented by different physicalquantities and its concept and calculation method are notunique (e traditional ductility coefficients include thedisplacement ductility coefficient angular ductility co-efficient curvature ductility coefficient and energy duc-tility coefficient

At present the limit state design method requires us tonot only ensure the bearing capacity of the structure butalso give the structure ductility On one hand a structurewith good ductility can absorb a large amount of powerbefore failing On the other hand there are obvious de-formation signs before the damage which can preventsudden damage caused by an overload (e FRP materialplays its role after the yielding of steel bar and its ultimatetensile strain is smaller than that of the steel bar

Additionally the stress-strain relationship is linear thusthe ductility of concrete members reinforced with FRP islower than that of the members without reinforcement Toqualitatively describe and measure the reduction of theductility after reinforcement three different ductilitycoefficients are used for analyzing the ductility perfor-mance of reinforced concrete bridge decks after rein-forcement on the basis of the failure modes and load-deflection curves (e displacement coefficient is the ratioof the ultimate deformation to the yield deformationwhich is based on the load-deflection relationship [181] asindicated by

λΔ ΔuΔy

(3)

where λΔ is the displacement coefficient Δu represents thedeflection of the midspan of the beam corresponding to theultimate load and Δy represents the deflection corre-sponding to the yield load Reinforced beams strengthenedwith NSM FRP bars exhibited lower ductility than theunreinforced members (e displacement coefficients of thereinforced beams were reduced by 313ndash667 [37]

(e energy ductility coefficient is calculated using theamount of deformation energy absorbed according to theload-deflection curve or load-curvature curve (e energyductility coefficient is given as follows

λw Wu

Wy

(4)

where λw is the energy ductility coefficient Wu and Wy

represent the deformation energy values of the memberscorresponding to the ultimate load and yield load respec-tively and they are determined by calculating the areaenclosed by the measured load-deflection or load-curvaturecurve and the X-axis

(e energy ductility coefficient describes the ability ofthe member to absorb energy after yielding and thedisplacement ductility coefficient is calculated based onthe deflection value of a single point With the ad-vancement of research scholars have realized the limi-tation of the traditional ductility coefficient and proposeda comprehensive ductility coefficient considering thebearing capacity and deformation [182] (e compre-hensive ductility coefficient is determined as follows

J SJDJ Mu

Mc

emptyu

emptyc

(5)

where J is the comprehensive ductility coefficientSJ (MuMc) is the bearing capacity factor DJ (emptyuemptyc)

is the deformation coefficient Mu represents the ultimatebending momentemptyu represents the ultimate curvature andMc and emptyc represent the bending moment and curvaturewhen the compressive strain of the concrete at the bottomof the beam is 0001 respectively (e comprehensiveductility coefficient which depends on the bearing ca-pacity factor and deformation coefficient is more com-prehensive in the safety reserve of structures orcomponents


5 Conclusions

Although FRP materials cannot replace traditional steel andconcrete materials over large areas they are expected tobecome necessary complements to the traditional structuralmaterials (e use of FRP materials enables challengingengineering problems to be easily solved presents newdevelopment opportunities in civil engineering and yieldssignificant economic benefits (e objectives of this studywere to enhance researchersrsquo understanding of thestrengthening methods for bridge structures and to improvethe reinforcement techniques for civil engineering andbuilding construction

(is paper discussed the development and application ofFRP materials and the strengthening techniques for bridgestructures Bridge structures bear traffic loads directly(e loaddistribution is highly irregular and the failure law is morecomplex than those for other structures For strengtheningcompared with traditional steel FRP materials exhibit betterapplication prospects in the field of reinforcement owing totheir light weight high strength and corrosion resistance EBFRP laminates are widely used for strengthening howeverNSMFRP bars havemore significant advantages and have beenthe subject of numerous studies Moreover research on thebonding problem of reinforcement technology has beenconducted for many years (e application of anchoragemeasures improves the cooperative working performancebetween the FRP materials and concrete which alleviates thisproblem to a certain extent

(e bridge decks and beams are usually considered asstrips to study the bending performance however inpractice the bridge deck is restrained by the supportingbeam and produces compressive membrane action It isnecessary to consider the effects of boundary supportconditions on the flexural reinforcement performance of thebridge deck A calculation formula for the bearing capacityof the bridge deck after strengthening considering the effectof the compressive membrane action should be establishedMoreover the bridge deck usually bears a local area loadtireload thus it is necessary to analyze the mechanical per-formance and failure mechanism of the reinforced bridgedeck under the local loads

(e bridge decks and beams are important componentsof bridge structures Reasonable and effective strengtheningmethods have been proposed for repairing damaged bridgesand improving the bearing capacity of existing bridgeswhich can extend the service life of old bridge structures fortraffic and transportation and yield significant economicbenefits

Conflicts of Interest

(e authors declare that there are no conflicts of interestregarding the publication of this paper

Authorsrsquo Contributions

HuWL conceptualized this study HuWL was responsiblefor the methodology investigation was conducted by Hu

WL and Yuan HY data curation was performed by YuanHY Hu WL prepared the original draft Li Y performedreview and editing visualization was performed by YuanHY and Li Y supervised the study All authors have readand agreed to the published version of the manuscript

Acknowledgments

(e authors disclosed receipt of the following financialsupport for the research authorship andor publication ofthis article this work was financially supported by theNatural Science Basic Research Program of Shannxi (Pro-gram No 2020JQ-377)

References

[1] A Costa and J Appleton ldquoCase studies of concrete dete-rioration in a marine environment in Portugalrdquo Cement andConcrete Composites vol 24 no 1 pp 169ndash179 2002

[2] M A Pech-Canul and P Castro ldquoCorrosion measurementsof steel reinforcement in concrete exposed to a tropicalmarine atmosphererdquo Cement and Concrete Research vol 32no 3 pp 491ndash498 2002

[3] X Shi N Xie K Fortune and J Gong ldquoDurability of steelreinforced concrete in chloride environments an overviewrdquoConstruction and Building Materials vol 30 pp 125ndash1382012

[4] M Safehian and A A Ramezanianpour ldquoAssessment ofservice life models for determination of chloride penetrationinto silica fume concrete in the severe marine environmentalconditionrdquo Construction and Building Materials vol 48pp 287ndash294 2013

[5] B Ji R Liu C Chen HMaeno and X Chen ldquoEvaluation onroot-deck fatigue of orthotropic steel bridge deckrdquo Journal ofConstructional Steel Research vol 90 no nov pp 174ndash1832013

[6] B-J Han S-I Yoon B-J Choi J-W Choi and S-K ParkldquoAnalysis study on fatigue stress on the orthotropic steel deckapplied polymer concrete pavementrdquo Journal of the KoreaInstitute for Structural Maintenance and Inspection vol 18no 5 pp 68ndash77 2014

[7] H Fang F Zou W Liu C Wu Y Bai and D HuildquoMechanical performance of concrete pavement reinforcedby CFRP grids for bridge deck applicationsrdquo Composites PartB Engineering vol 110 pp 315ndash335 2017

[8] M Onofrei Durability of GFRP Reinforced Concrete in FieldStructures American Concrete Institute Indiana IN USA2005

[9] M A Erki and S H Rizkalla ldquoFRP reinforcement forconcrete structuresrdquo Concrete International vol 15pp 48ndash53 1993

[10] R A Hawileh H A Rasheed J A Abdalla and A K Al-Tamimi ldquoBehavior of reinforced concrete beams strength-ened with externally bonded hybrid fiber reinforced polymersystemsrdquo Materials amp Design vol 53 pp 972ndash982 2014

[11] W Xue Y Tan and L Zeng ldquoFlexural response predictionsof reinforced concrete beams strengthened with prestressedCFRP platesrdquo Composite Structures vol 92 no 3pp 612ndash622 2010

[12] J Sim and H Oh ldquoStructural behavior of strengthenedbridge deck specimens under fatigue loadingrdquo EngineeringStructures vol 26 no 14 pp 2219ndash2230 2004


[13] A El-Ragaby E El-Salakawy and B Benmokrane ldquoFatigueanalysis of concrete bridge deck slabs reinforced withE-glassvinyl ester FRP reinforcing barsrdquo Composites Part BEngineering vol 38 no 5-6 pp 703ndash711 2007

[14] H Toutanji and Y Deng ldquoStrength and durability perfor-mance of concrete axially loaded members confined withAFRP composite sheetsrdquo Composites Part B Engineeringvol 33 no 4 pp 255ndash261 2002

[15] B Benmokrane B Zhang and A Chennouf ldquoTensileproperties and pullout behaviour of AFRP and CFRP rodsfor grouted anchor applicationsrdquo Construction and BuildingMaterials vol 14 no 3 pp 157ndash170 2000

[16] S El-Gamal and O AlShareedah ldquoBehavior of axially loadedlow strength concrete columns reinforced with GFRP barsand spiralsrdquo Engineering Structures vol 216 p 110732 2020

[17] P Zhang Y Hu Y Pang et al ldquoInfluence factors analysis ofthe interfacial bond behavior between GFRP plates con-creterdquo Structures vol 26 pp 79ndash91 2020

[18] P FengDevelopment and Study on an Innovative FRP BridgeDeck Tsinghua University Beijing China 2004

[19] R Realfonzo E Martinelli A Napoli and B NunziataldquoExperimental investigation of the mechanical connectionbetween FRP laminates and concreterdquo Composites Part BEngineering vol 45 no 1 pp 341ndash355 2013

[20] W He XWang and ZWu ldquoFlexural behavior of RC beamsstrengthened with prestressed and non-prestressed BFRPgridsrdquo Composite Structures vol 246 p 112381 2020

[21] M Jalali M K Sharbatdar J-F Chen and F Jandaghi AlaeeldquoShear strengthening of RC beams using innovative man-ually made NSM FRP barsrdquo Construction and BuildingMaterials vol 36 pp 990ndash1000 2012

[22] H-T Wang and G Wu ldquoCrack propagation prediction ofdouble-edged cracked steel beams strengthened with FRPplatesrdquo in-Walled Structures vol 127 pp 459ndash4682018

[23] A M Sayed X Wang and Z Wu ldquoFinite element modelingof the shear capacity of RC beams strengthened with FRPsheets by considering different failure modesrdquo Constructionand Building Materials vol 59 pp 169ndash179 2014

[24] R El-Hacha and M Elbadry ldquoStrengthening concrete beamswith externally prestressed carbon fiber composite cablesrdquo inProceedings of the International Conference on Fiber Rein-forced Polymers for Reinforced Concrete Structures Cam-bridge UK July 2001

[25] H Oh and J Sim ldquoPunching shear strength of strengtheneddeck panels with externally bonded platesrdquo Composites PartB Engineering vol 35 no 4 pp 313ndash321 2004

[26] Y Yang M F M Fahmy J Cui Z Pan and J ShildquoNonlinear behavior analysis of flexural strengthening of RCbeams with NSM FRP laminatesrdquo Structures vol 20pp 374ndash384 2019

[27] R A Hawileh H A Musto J A Abdalla and M Z NaserldquoFinite element modeling of reinforced concrete beamsexternally strengthened in flexure with side-bonded FRPlaminatesrdquo Composites Part B Engineering vol 173p 106952 2019

[28] K Khorramian and P Sadeghian ldquoPerformance of high-modulus near-surface-mounted FRP laminates forstrengthening of concrete columnsrdquo Composites Part BEngineering vol 164 pp 90ndash102 2019

[29] R A Hawileh W Nawaz J A Abdalla and E I SaqanldquoEffect of flexural CFRP sheets on shear resistance of rein-forced concrete beamsrdquo Composite Structures vol 122pp 468ndash476 2015

[30] R (amrin and H S Zaidir ldquoShear capacity of reinforcedconcrete beams strengthened with web side bonded CFRPsheetsrdquo in International Conference on Sustainable CivilEngineering Structures and Construction Materials Cedex AA Awaludin T Matsumoto S Pessiki et al Eds EDPSciences Les Ulis France 2019

[31] R (amrin S Haris and Zaidir ldquoShear strengthening ofreinforced concrete beams with near surface mounted steelbarsrdquo in International Conference on Advances in Civil andEnvironmental Engineering Cedex A M Olivia A MartoK Yamamoto et al Eds EDP Sciences Les Ulis France2019

[32] E I Saqan H A Rasheed and T Alkhrdaji ldquoEvaluation ofthe seismic performance of reinforced concrete framesstrengthened with CFRP fabric and NSM barsrdquo CompositeStructures vol 184 pp 839ndash847 2018

[33] R A Hawileh W Nawaz J A Abdalla and E I SaqanExternal Strengthening of Shear Deficient Reinforced ConcreteBeams with Flexural CFRP Laminates Destech PublicationsInc Lancaster PA USA 2015

[34] H H Mhanna R A Hawileh and J A Abdalla ldquoShearstrengthening of reinforced concrete beams using CFRPwrapsrdquo in 3rd International Conference on Structural In-tegrity P Moreira and P J S Tavares Eds pp 214ndash221Elsevier Science Amsterdam Netherlands 2019

[35] A S D Salama R A Hawileh and J A Abdalla ldquoPer-formance of externally strengthened RC beams with side-bonded CFRP sheetsrdquo Composite Structures vol 212pp 281ndash290 2019

[36] M T Junaid A Elbana and S Altoubat ldquoFlexural responseof geopolymer and fiber reinforced geopolymer concretebeams reinforced with GFRP bars and strengthened usingCFRP sheetsrdquo Structures vol 24 pp 666ndash677 2020

[37] M Abdallah F Al Mahmoud A Khelil J Mercier andB Almassri ldquoAssessment of the flexural behavior of con-tinuous RC beams strengthened with NSM-FRP bars ex-perimental and analytical studyrdquo Composite Structuresvol 242 p 112127 2020

[38] A Torabian B Isufi D Mostofinejad and A Pinho RamosldquoFlexural strengthening of flat slabs with FRP compositesusing EBR and EBROG methodsrdquo Engineering Structuresvol 211 p 110483 2020

[39] M Tahir Z Wang K M Ali and H F Isleem ldquoShearbehavior of concrete beams reinforced with CFRP sheet stripstirrups using wet-layup techniquerdquo Structures vol 22pp 43ndash52 2019

[40] M Kazemi J Li S Lahouti Harehdasht N YousefiehS Jahandari and M Saberian ldquoNon-linear behaviour ofconcrete beams reinforced with GFRP and CFRP barsgrouted in sleevesrdquo Structures vol 23 pp 87ndash102 2020

[41] R Park and J Jang ldquoPerformance improvement of carbonfiberpolyethylene fiber hybrid compositesrdquo Journal ofMaterials Science vol 34 1999

[42] A S Azevedo J P Firmo J R Correia and C TiagoldquoInfluence of elevated temperatures on the bond behaviourbetween concrete and NSM-CFRP stripsrdquo Cement andConcrete Composites vol 111 p 103603 2020

[43] R Sonnenschein K Gajdosova and I Holly ldquoFRP com-posites and their using in the construction of bridgesrdquoProcedia Engineering vol 161 pp 477ndash482 2016

[44] L Alexandre S C Alexandre and B E D MirandaldquoMechanical properties of glass fiber reinforced polymersmembers for structural applicationsrdquo Materials Researchvol 18 no 6 pp 1372ndash1383 2015


[45] S Al-Obaidi Y M Saeed and F N Rad ldquoFlexuralstrengthening of reinforced concrete beams with NSM-CFRP bars using mechanical interlockingrdquo Journal ofBuilding Engineering vol 31 p 101422 2020

[46] Z Huang Y Zhao J Zhang and Y Wu ldquoPunching shearbehaviour of concrete slabs reinforced with CFRP gridsrdquoStructures vol 26 pp 617ndash625 2020

[47] M H Meisami D Mostofinejad and H NakamuraldquoPunching shear strengthening of two-way flat slabs usingCFRP rodsrdquo Composite Structures vol 99 pp 112ndash122 2013

[48] B Zhang R Masmoudi and B Benmokrane ldquoBehaviour ofone-way concrete slabs reinforced with CFRP grid rein-forcementsrdquo Construction and Building Materials vol 18no 8 pp 625ndash635 2004

[49] L K Amaireh and A Al-Tamimi ldquoOptimum configurationof CFRP composites for strengthening of reinforced concretebeams considering the contact constraintrdquo ProcediaManufacturing vol 44 pp 350ndash357 2020

[50] T Siwowski B Piatek P Siwowska and A Wiater ldquoDe-velopment and implementation of CFRP post-tensioningsystem for bridge strengtheningrdquo Engineering Structuresvol 207 p 110266 2020

[51] B Ramesh and S Eswari ldquoStructural response of GFRPstrengthened hybrid fibre reinforced concrete beamsrdquo Ma-terials Today Proceedings vol 33 2020

[52] J M F d Paiva A D N d Santos and M C RezendeldquoMechanical and morphological characterizations of carbonfiber fabric reinforced epoxy composites used in aeronauticalfieldrdquo Materials Research vol 12 no 3 pp 367ndash374 2009

[53] R A Hawileh A Abu-Obeidah J A Abdalla and A Al-Tamimi ldquoTemperature effect on the mechanical properties ofcarbon glass and carbon-glass FRP laminatesrdquo Constructionand Building Materials vol 75 pp 342ndash348 2015

[54] Y Zhou X Zheng F Xing L Sui Y Zheng and X HuangldquoInvestigation on the electrochemical and mechanical per-formance of CFRP and steel-fiber composite bar used forimpressed current cathodic protection anoderdquo Constructionand Building Materials vol 255 2020

[55] S C Brown C Robert V Koutsos and D Ray ldquoMethods ofmodifying through-thickness electrical conductivity of CFRPfor use in structural health monitoring and its effect onmechanical properties-a reviewrdquo Composites Part A-AppliedScience and Manufacturing vol 133 2020

[56] D Mostofinejad and S M Shameli ldquoExternally bonded re-inforcement in grooves (EBRIG) technique to postponedebonding of FRP sheets in strengthened concrete beamsrdquoConstruction and BuildingMaterials vol 38 pp 751ndash758 2013

[57] P Zhang D Lei Q Ren J He H Shen and Z YangldquoExperimental and numerical investigation of debondingprocess of the FRP plate-concrete interfacerdquo Constructionand Building Materials vol 235 p 117457 2020

[58] M Miralami M R Esfahani and M TavakkolizadehldquoStrengthening of circular RC column-foundation connec-tions with GFRPSMA bars and CFRP wrapsrdquo CompositesPart B Engineering vol 172 pp 161ndash172 2019

[59] M N Sheikh and F Legeron ldquoPerformance based seismicassessment of bridges designed according to CanadianHighway Bridge Design Coderdquo Canadian Journal of CivilEngineering vol 41 no 9 pp 777ndash787 2014

[60] H Tobbi A S Farghaly and B Benmokrane ldquoBehavior ofconcentrically loaded fiber-reinforced polymer reinforcedconcrete columns with varying reinforcement types andratiosrdquo ACI Structural Journal vol 111 no 2 pp 375ndash3852014

[61] H M Mohamed and B Benmokrane ldquoDesign and perfor-mance of reinforced concrete water chlorination tank totallyreinforced with GFRP bars case studyrdquo Journal of Com-posites for Construction vol 18 no 1 Article ID 050130012014

[62] M H Mohamed F Ghrib A Hadhood et al ldquoEfficiency ofglass-fiber reinforced-polymer (GFRP) discrete hoops andbars in concrete columns under combined axial and flexuralloadsrdquo Composites Part B Engineering vol 114 2017

[63] A Hadhood H M Mohamed B Benmokrane A Nanniand C K Shield ldquoAssessment of design guidelines of con-crete columns reinforced with glass fiber-reinforced polymerbarsrdquo ACI Structural Journal vol 116 no 4 pp 193ndash2072019

[64] A H Ali M H Mohamed C Omar B Brahim andG Faouzi ldquoShear resistance of RC circular members withFRP discrete hoops versus spiralsrdquo Engineering Structuresvol 174 pp 688ndash700 2018

[65] T Cadenazzi G Dotelli M Rossini S Nolan and A NannildquoLife-cycle cost and life-cycle assessment analysis at thedesign stage of a fiber-reinforced polymer-reinforced con-crete bridge in Floridardquo Advances in Civil EngineeringMaterials vol 8 no 2 p 20180113 2019

[66] A Wiater and T Siwowski ldquoServiceability and ultimatebehaviour of GFRP reinforced lightweight concrete slabsexperimental test versus code predictionrdquo CompositeStructures vol 239 p 112020 2020

[67] V Dhand G Mittal K Y Rhee S-J Park and D Hui ldquoAshort review on basalt fiber reinforced polymer compositesrdquoComposites Part B Engineering vol 73 pp 166ndash180 2015

[68] P Banibayat and A Patnaik ldquoVariability of mechanicalproperties of basalt fiber reinforced polymer bars manu-factured by wet-layup methodrdquo Materials amp Design(1980ndash2015) vol 56 pp 898ndash906 2014

[69] B Wei H Cao and S Song ldquoDegradation of basalt fibre andglass fibreepoxy resin composites in seawaterrdquo CorrosionScience vol 53 no 1 pp 426ndash431 2011

[70] X Wang Z Wu G Wu H Zhu and F Zen ldquoEnhancementof basalt FRP by hybridization for long-span cable-stayedbridgerdquo Composites Part B Engineering vol 44 no 1pp 184ndash192 2013

[71] V Lopresto C Leone and I De Iorio ldquoMechanical char-acterisation of basalt fibre reinforced plasticrdquo CompositesPart B Engineering vol 42 no 4 pp 717ndash723 2011

[72] P Larrinaga C Chastre H C Biscaia and J T San-JoseldquoExperimental and numerical modeling of basalt textilereinforced mortar behavior under uniaxial tensile stressrdquoMaterials amp Design vol 55 pp 66ndash74 2014

[73] V Fiore G Di Bella and A Valenza ldquoGlass-basaltepoxyhybrid composites for marine applicationsrdquo Materials ampDesign vol 32 no 4 pp 2091ndash2099 2011

[74] T M Borhan ldquoProperties of glass concrete reinforced withshort basalt fibrerdquo Materials amp Design vol 42 pp 265ndash2712012

[75] J Sim C Park and D Y Moon ldquoCharacteristics of basaltfiber as a strengthening material for concrete structuresrdquoComposites Part B Engineering vol 36 no 6-7 pp 504ndash5122005

[76] X Hu and T Shen ldquo(e applications of the CBF in warindusty and civil fieldsrdquo Hi-Tech Fiber Application vol 30no 6 pp 7ndash13 2005

[77] Y Nakayama H Nakai and T Kanakubo ldquoBond beha-bior between deformed aramid fiber-reinforced plasticreinforcement and concreterdquo in Proceedings of the 14th


World Conference on Earthquake Engineering BeijingChina October 2008

[78] R E Wilfong and J Zimmerman ldquoStrength and durabilitycharacteristics of Kevlar aramid fibrerdquo Applied PolymerSymposia vol 31 pp 1ndash21 1977

[79] M Saafi and H Toutanji ldquoFlexural capacity of prestressedconcrete beams reinforced with aramid fiber reinforcedpolymer (AFRP) rectangular tendonsrdquo Construction andBuilding Materials vol 12 no 5 pp 245ndash249 1998

[80] S Bagherpour Fibre Reinforced R Composites M SalehHosam El-Din Ed p 167 Springer Berlin Germany 2012

[81] C B Nayak ldquoExperimental and numerical investigation oncompressive and flexural behavior of structural steel tubularbeams strengthened with AFRP compositesrdquo Journal of KingSaud University-Engineering Sciences 2020

[82] R Sakurada T Shimomura K Maruyama andS Matsubara ldquoBending behavior of rc beam reinforced withbraided aramid FRP barrdquo in Proceedings of the e 31stConference on Our World in Concrete and Structures Sin-gapore August 2006

[83] S Yin R Tuladhar R A Shanks et al ldquoFiber preparationand mechanical properties of recycled polypropylene forreinforcing concreterdquo Journal of Applied Polymer Sciencevol 132 2015

[84] N Banthia and V Cheng ldquoShrinkage cracking in polyolefinfiber-reinforced concreterdquo ACI Structural Journal vol 97no 4 pp 432ndash437 2000

[85] N Eswari ldquoDuctility response of hybrid fibre reinforcedconcrete beamsrdquo Journal of Urban and Environmental En-gineering vol 11 no 2 pp 174ndash179 2017

[86] D Jerrett and J T Cuddington ldquoBroadening the statisticalsearch for metal price super cycles to steel and relatedmetalsrdquo Resources Policy vol 33 no 4 pp 188ndash195 2008

[87] V M Karbhari and L Zhao ldquoIssues related to compositeplating and environmental exposure effects on composite-concrete interface in external strengtheningrdquo CompositeStructures vol 40 1997

[88] A Gharachorlou and A Ramezanianpour ldquoResistance ofconcrete specimens strengthened with FRP sheets to thepenetration of chloride ionsrdquo Arabian Journal for Scienceand Engineering vol 35 2010

[89] P Boer L Holliday and T H-K Kang ldquoIndependent en-vironmental effects on durability of fiber-reinforced polymerwraps in civil applications a reviewrdquo Construction andBuilding Materials vol 48 pp 360ndash370 2013

[90] M A G Silva B S da Fonseca andH Biscaia ldquoOn estimatesof durability of FRP based on accelerated testsrdquo CompositeStructures vol 116 pp 377ndash387 2014

[91] D Zhao J Pan Y Zhou L Sui and Z Ye ldquoNew types ofsteel-FRP composite bar with round steel bar inner coremechanical properties and bonding performances in con-creterdquo Construction and Building Materials vol 242p 118062 2020

[92] J W Schmidt A Bennitz B Taljsten P Goltermann andH Pedersen ldquoMechanical anchorage of FRP tendons-a lit-erature reviewrdquo Construction and Building Materials vol 32pp 110ndash121 2012

[93] H Zhang L He and G Li ldquoBond failure performancesbetween near-surface mounted FRP bars and concrete forflexural strengthening concrete structuresrdquo EngineeringFailure Analysis vol 56 pp 39ndash50 2015

[94] T Uomoto H Mutsuyoshi F Katsuki and S Misra ldquoUse offiber reinforced polymer composites as reinforcing material

for concreterdquo Journal of Materials in Civil Engineeringvol 14 no 3 pp 191ndash209 2002

[95] E Y Sayed-Ahmed and N G Shrive ldquoA new steel anchoragesystem for post-tensioning applications using carbon fibrereinforced plastic tendonsrdquo Canadian Journal of Civil En-gineering vol 25 no 1 pp 113ndash127 1998

[96] X Yang W-Y Gao J-G Dai and Z-D Lu ldquoShearstrengthening of RC beams with FRP grid-reinforced ECCmatrixrdquo Composite Structures vol 241 p 112120 2020

[97] J P Firmo J R Correia D Pitta C Tiago andM R T Arruda ldquoExperimental characterization of the bondbetween externally bonded reinforcement (EBR) CFRP stripsand concrete at elevated temperaturesrdquo Cement and Con-crete Composites vol 60 pp 44ndash54 2015

[98] J P Firmo J R Correia D Pitta C Tiago andM R T Arruda ldquoBond behavior between near-surface-mounted CFRP strips and concrete at high temperaturesrdquoJournal of Composites for Construction vol 19 no 4 2015

[99] P J Burke L A Bisby and M F Green ldquoEffects of elevatedtemperature on near surface mounted and externally bondedFRP strengthening systems for concreterdquo Cement andConcrete Composites vol 35 no 1 pp 190ndash199 2013

[100] N S Ottosen ldquoFailure and elasticity of concreterdquo DanishAtomic Energy Commission Risoe Research EstablishmentInternational Atomic Energy Agency Vienna AustriaRISO-M-1801 1975

[101] G H Beguin ldquoDiscussion of ldquoreinforced concrete beamswith plates glued to their soffitsrdquo by deric john oehlers(august 1992 vol 118 No 8)rdquo Journal of Structural Engi-neering vol 120 no 4 pp 1368-1369 1994

[102] T M Roberts ldquoApproximate analysis of shear and normalstress concentrations in the adhesive layer of plated RCbeamsrdquoe Structural Engineer vol 67 no 12 pp 229ndash2331989

[103] R Jones R N Swamy and A Charif ldquoPlate separation andanchorage of reinforced concrete beams strengthened byepoxy-bonded steel platerdquo Structural Engineer vol 66 no 51988

[104] J Sim H Oh and C Meyer ldquoStructural assessment ofexternally strengthened bridge deck panelsrdquo Applied Com-posite Materials vol 13 pp 99ndash114 2006

[105] M N Dai T K Chan and H K Cheong ldquoBrittle failure andbond development length of CFRP-concrete beamsrdquo Journalof Composites for Construction vol 5 no 1 pp 12ndash17 2001

[106] P Mukhopadhyaya and N Swamy ldquoInterface shear stress anew design criterion for plate debondingrdquo Journal ofComposites for Construction vol 5 no 1 pp 35ndash43 2001

[107] H F IsleemM Tahir and ZWang ldquoAxial stress-strainmodeldeveloped for rectangular RC columns confined with FRPwraps and anchorsrdquo Structures vol 23 pp 779ndash788 2020

[108] A de Diego A Arteaga and J Fernandez ldquoStrengthening ofsquare concrete columns with composite materials Inves-tigation on the FRP jacket ultimate strainrdquo Composites PartB Engineering vol 162 pp 454ndash460 2019

[109] G Lin and J G Teng ldquoAdvanced stress-strain model forFRP-confined concrete in square columnsrdquo Composites PartB Engineering vol 197 p 108149 2020

[110] C Bakis A Ganjehlou D Kachlakev et al Guide for theDesign and Construction of Externally Bonded FRP Systemsfor Strengthening Concrete Structures p 440 AmericanConcrete Institute Farmington Hills MI USA 2002

[111] Japan Concrete Engineering Series Recommendations forupgrading of concrete structures with use of continuous fibre


sheets Vol 41 Japan Society of Civil Engineers TokyoJapan 2001

[112] A F Ashour S A El-Refaie and S W Garrity ldquoFlexuralstrengthening of RC continuous beams using CFRP lami-natesrdquo Cement and Concrete Composites vol 26 no 7pp 765ndash775 2004

[113] J Pan and Y-F Wu ldquoAnalytical modeling of bond behaviorbetween FRP plate and concreterdquo Composites Part B En-gineering vol 61 pp 17ndash25 2014

[114] J G Teng S T Smith J Yao and J F Chen ldquoIntermediatecrack-induced debonding in RC beams and slabsrdquo Con-struction and Building Materials vol 17 no 6-7 pp 447ndash462 2003

[115] S Amiri and S Behzad Talaeitaba ldquoPunching shearstrengthening of flat slabs with EBROG and EBRIG - FRPstripsrdquo Structures vol 26 pp 139ndash155 2020

[116] P K V R Padalu Y Singh and S Das ldquoOut-of-planeflexural behaviour of masonry wallettes strengthened usingFRP composites and externally bonded grids comparativestudyrdquo Composites Part B Engineering vol 176 p 1073022019

[117] X Yang W-Y Gao J-G Dai Z-D Lu and K-Q YuldquoFlexural strengthening of RC beams with CFRP grid-reinforced ECC matrixrdquo Composite Structures vol 189pp 9ndash26 2018

[118] V M Karbhari Use of Composite Materials in Civil Infra-structure in Japan International Technology Research In-stitute World Technology Division Hsinchu Taiwan 1998

[119] J J Brunton L C Bank and M G Oliva ldquoPunching shearfailure in double-layer pultruded FRP grid reinforced con-crete bridge decksrdquo Advances in Structural Engineeringvol 15 no 4 pp 601ndash613 2012

[120] C Papanicolaou T Triantafillou and M Lekka ldquoExternallybonded grids as strengthening and seismic retrofitting ma-terials of masonry panelsrdquo Construction and Building Ma-terials vol 25 no 2 pp 504ndash514 2011

[121] L Ding S Rizkalla GWu and Z SWu BondMechanism ofCarbon Fiber Reinforced Polymer Grid to Concrete SpringerBerlin Germany 2010

[122] A H Rahman C Y Kingsley and K Kobayashi ldquoServiceand ultimate load behavior of bridge deck reinforced withcarbon FRP gridrdquo Journal of Composites for Constructionvol 4 no 1 pp 16ndash23 2000

[123] N Banthia M Al-Asaly and S Ma ldquoBehavior of concreteslabs reinforced with fiber-reinforced plastic gridrdquo Journal ofMaterials in Civil Engineering vol 7 no 4 pp 252ndash2571995

[124] X Wang Z Peng Z Wu and S Sun ldquoHigh-performancecomposite bridge deck with prestressed basalt fiber-reinforcedpolymer shell and concreterdquo Engineering Structures vol 201p 109852 2019

[125] Q Wu S Xiao and K Iwashita ldquoExperimental study on theinterfacial shear stress of RC beams strengthened withprestressed BFRP rodrdquo Results in Physics vol 10 pp 427ndash433 2018

[126] T Lou and T L Karavasilis ldquoNumerical evaluation ofprestressed steel-concrete composite girders with externalFRP or steel tendonsrdquo Journal of Constructional Steel Re-search vol 162 p 105698 2019

[127] M Aslam P Shafigh M Z Jumaat and S N R ShahldquoStrengthening of RC beams using prestressed fiber rein-forced polymers-a reviewrdquo Construction and Building Ma-terials vol 82 no may 1 pp 235ndash256 2015

[128] A H J M Vervuurt N Kaptijn and W B GrundlehnerldquoCarbon-based tendons in the dintelhaven bridge (eNetherlandsrdquo Structural Concrete vol 4 no 1 pp 1ndash112003

[129] T Noro and T Hojo ldquoApplication of carbon-fiber cables forcable-supported structuresrdquo IABSE Symposium Reportvol 86 no 7 2002

[130] B Gaubinger and J Kollegger ldquoDevelopment of an an-chorage system for CFRP tendonsrdquo IABSE Symposium Re-port vol 86 no 7 pp 95ndash102 2002

[131] J Horvatits and J Kollegger External CFRP Tendons forBridge Strengthening in Austria ICE Publishing LondonUK 2005

[132] H Nordin and B Taljsten ldquoStrengthening of concretestructures by external prestressingrdquo in Proceedings of theird International Conference on Bridge MaintenanceSafety and Management Porto Portugal July 2006

[133] F Matta A Nanni A Abdelrazaq D Gremel and R KochldquoExternally post-tensioned carbon FRP bar system for de-flection controlrdquo Construction and Building Materialsvol 23 no 4 pp 1628ndash1639 2009

[134] C Macdougall M Green and L Amato ldquoCFRP tendons forthe repair of post-tensioned unbonded concrete buildingsrdquoJournal of Performance of Constructed Facilities vol 25no 3 pp 149ndash157 2009

[135] A Nanni C E Bakis and T E Boothby ldquoTest methods forFRP-concrete systems subjected to mechanical loads state ofthe art reviewrdquo Journal of Reinforced Plastics and Compositesvol 14 no 6 pp 524ndash558 1995

[136] Y Xiang B Miller A Nanni and E Charles ldquoBakisCharacterization of CFRP rods used as near-surfacemounted reinforcementrdquo in Proceedings of the 8th Inter-national Conference on Structural Faults and Repair MainzGermany September 1999

[137] Z Yu ldquoBehaviour of concrete bridge deck slabs strengthenedwith NSM FRP barsrdquo in Proceedings of the InternationalConference on Fibre-Reinforced Polymer Composites in CivilEngineering Hong Kong China December 2016

[138] G Foret and O Limam ldquoExperimental and numericalanalysis of RC two-way slabs strengthened with NSM CFRProdsrdquo Construction and Building Materials vol 22 no 10pp 2025ndash2030 2008

[139] O Asplund ldquoStrengthening bridge slabs with grouted re-inforcementrdquo Journal of American Concrete Institute vol 20no 6 pp 397ndash406 1949

[140] P Casadei N Galati R Parretti A Nanni and P GalatiStrengthening of a Bridge Using Two FRP Technologiespp 219ndash238 ACI Publication Farmington Hills MI USA2003

[141] T Alkhrdaji A Nanni G Chen and M Barker ldquoUpgradingthe transportation infrastructure solid RC decks strength-ened with FRPrdquo Concrete International vol 21 no 10 1999

[142] L De Lorenzis A Rizzo and A La Tegola ldquoA modified pull-out test for bond of near-surface mounted FRP rods inconcreterdquo Composites Part B Engineering vol 33 no 8pp 589ndash603 2002

[143] T Martin S Taylor D Robinson and D Cleland ldquoBasaltfibre reinforced polymer bar strengthening compared toarching actions within slabsrdquo in Proceedings of the 6th In-ternational Conference on FRP Composites in Civil Engi-neering CICE Rome Italy June 2012

[144] Q Wang T Li H Zhu W Su and X Hu ldquoBond en-hancement for NSM FRP bars in concrete using different


anchorage systemsrdquo Construction and Building Materialsvol 246 p 118316 2020

[145] Q Wang H Zhu T Li G Wu and X Hu ldquoBond per-formance of NSM FRP bars in concrete with an innovativeadditional ribs anchorage system an experimental studyrdquoConstruction and Building Materials vol 207 pp 572ndash5842019

[146] C Barris P Sala J Gomez and L Torres ldquoFlexural be-haviour of FRP reinforced concrete beams strengthened withNSMCFRP stripsrdquo Composite Structures vol 241 p 1120592020

[147] I A Sharaky L Torres J Comas and C Barris ldquoFlexuralresponse of reinforced concrete (RC) beams strengthenedwith near surface mounted (NSM) fibre reinforced polymer(FRP) barsrdquo Composite Structures vol 109 pp 8ndash22 2014

[148] S S Zhang T Yu and G M Chen ldquoReinforced concretebeams strengthened in flexure with near-surface mounted(NSM) CFRP strips current status and research needsrdquoComposites Part B Engineering vol 131 pp 30ndash42 2017

[149] M Ibrahim T Wakjira and U Ebead ldquoShear strengtheningof reinforced concrete deep beams using near-surfacemounted hybrid carbonglass fibre reinforced polymerstripsrdquo Engineering Structures vol 210 p 110412 2020

[150] S S Zhang and J G Teng ldquoFinite element prediction ofplate-end cover separation in FRP-strengthened RC beamsrdquoin Proceedings of the International Symposium on StructuralEngineering Orlando FL USA May 2010

[151] A Michael C OrsquoNeill and M Ansley ldquoBridge decksstrenthened with near-surface mounted bars embedded incement-based groutrdquo Composites and Polycon vol 2 2007

[152] M Hosseini S Dias and J Barros ldquoBehaviour of RC slabsflexurally strengthened with presressed NSM CFRP lami-natesrdquo Joaquim Barros and Jose Sena-Cruz 2013

[153] D Lee and L Cheng ldquoAssessing the strengthening effect ofvarious near-surface-mounted FRP reinforcements onconcrete bridge slab overhangsrdquo Journal of Composites forConstruction vol 15 no 4 pp 615ndash624 2011

[154] S Shahriari and H Naderpour ldquoReliability assessment ofshear-deficient reinforced concrete beams externally bondedby FRP sheets having different configurationsrdquo Structuresvol 25 pp 730ndash742 2020

[155] S S Choobbor R A Hawileh A Abu-Obeidah andJ A Abdalla ldquoPerformance of hybrid carbon and basalt FRPsheets in strengthening concrete beams in flexurerdquo Com-posite Structures vol 227 p 111337 2019

[156] O R Abuodeh J A Abdalla and R A Hawileh ldquoPredictionof shear strength and behavior of RC beams strengthenedwith externally bonded FRP sheets using machine learningtechniquesrdquo Composite Structures vol 234 p 111698 2020

[157] A Hosny H Shaheen A Abdelrahman and T ElafandyldquoPerformance of reinforced concrete beams strengthened byhybrid FRP laminatesrdquo Cement and Concrete Compositesvol 28 no 10 pp 906ndash913 2006

[158] J Qi Z J Ma J Wang and Y Bao ldquoPost-cracking shearbehaviour of concrete beams strengthened with externallyprestressed tendonsrdquo Structures vol 23 pp 214ndash224 2020

[159] A Rizzo and L De Lorenzis ldquoModeling of debonding failurefor RC beams strengthened in shear with NSM FRP rein-forcementrdquo Construction and Building Materials vol 23no 4 pp 1568ndash1577 2009

[160] C Chen Y Yang J Yu et al ldquoEco-friendly and mechanicallyreliable alternative to synthetic FRP in externally bondedstrengthening of RC beams natural FRPrdquo CompositeStructures vol 241 p 112081 2020

[161] L Huang B Yan L Yan Q Xu H Tan and B KasalldquoReinforced concrete beams strengthened with externallybonded natural flax FRP platesrdquo Composites Part B Engi-neering vol 91 pp 569ndash578 2016

[162] D Gao D Fang P You G Chen and J Tang ldquoFlexuralbehavior of reinforced concrete one-way slabs strengthenedvia external post-tensioned FRP tendonsrdquo EngineeringStructures vol 216 p 110718 2020

[163] R El-Hacha and S H Rizkalla ldquoNear-surface-mountedfiber-reinforced polymer reinforcements for flexuralstrengthening of concrete structuresrdquo ACI StructuralJournal vol 101 no 5 pp 717ndash726

[164] A Bilotta F Ceroni E Nigro and M Pecce ldquoEfficiency ofCFRP NSM strips and EBR plates for flexural strengtheningof RC beams and loading pattern influencerdquo CompositeStructures vol 124 pp 163ndash175 2015

[165] G M Dalfre and J A O Barros ldquoFlexural strengthening ofRC continuous slab strips using NSM CFRP laminatesrdquoAdvances in Structural Engineering vol 14 no 6pp 1223ndash1245 2011

[166] Y-F Wu X-S Xu J-B Sun and C Jiang ldquoAnalyticalsolution for the bond strength of externally bonded rein-forcementrdquo Composite Structures vol 94 no 11pp 3232ndash3239 2012

[167] Y Wu Z Zhou Q Yang and W Chen ldquoOn shear bondstrength of FRP-concrete structuresrdquo Engineering Structuresvol 32 no 3 pp 897ndash905 2010

[168] J G Teng H Yuan and J F Chen ldquoFRP-to-concrete in-terfaces between two adjacent cracks theoretical model fordebonding failurerdquo International Journal of Solids andStructures vol 43 no 18-19 pp 5750ndash5778 2006

[169] R Seracino M R Raizal Saifulnaz and D J Oehlers ldquoGenericdebonding resistance of EB and NSM plate-to-concretejointsrdquo Journal of Composites for Construction vol 11 no 1pp 62ndash70 2007

[170] X Z Lu L P Ye J G Teng and J J Jiang ldquoMeso-scale finiteelement model for FRP sheetsplates bonded to concreterdquoEngineering Structures vol 27 no 4 pp 564ndash575 2005

[171] J-F Chen and J G Teng ldquoAnchorage strength models forFRP and steel plates bonded to concreterdquo Journal ofStructural Engineering vol 127 2001

[172] L C Hollaway ldquoA review of the present and future uti-lisation of FRP composites in the civil infrastructure withreference to their important in-service propertiesrdquo Con-struction and Building Materials vol 24 no 12 pp 2419ndash2445 2010

[173] Y H Mugahed Amran R Alyousef R S M RashidH Alabduljabbar and C-C Hung ldquoProperties and appli-cations of FRP in strengthening RC structures a reviewrdquoStructures vol 16 pp 208ndash238 2018

[174] R Selzer and K Friedrich ldquoMechanical properties andfailure behaviour of carbon fibre-reinforced polymer com-posites under the influence of moisturerdquo Composites Part AApplied Science and Manufacturing vol 28 no 6 pp 595ndash604 1997

[175] R Selzer and K Friedrich ldquoInluence of water up-take oninterlaminar fracture properties of carbon fibre-reinforcedpolymer compositesrdquo Journal of Materials Science vol 30no 2 pp 334ndash338 1995

[176] L Kumosa B Benedikt D Armentrout and M KumosaldquoMoisture absorption properties of unidirectional glasspolymer composites used in composite (non-ceramic) in-sulatorsrdquo Composites Part A Applied Science andManufacturing vol 35 no 9 pp 1049ndash1063 2004


[177] R Andrews E Grulke and G Kimber Mechanical Prop-erties of Carbon Fiber Composites for Environmental Appli-cations American Chemical Society Washington DC USA1996

[178] L Hollaway A (orne and R Quantrill ldquoExperimental andanalytical investigation of FRP strengthened beam responsePart Irdquo Magazine of Concrete Research vol 48 pp 331ndash3421996

[179] M Ali L Hollaway D Oehlers R Quantrill and A(orneldquoPredictions of the maximum plate end stresses of FRPstrengthened beams Part IIrdquoMagazine of Concrete Researchvol 50 pp 91-92 1998

[180] A M Ceci J R Casas and M Ghosn ldquoStatistical analysis ofexisting models for flexural strengthening of concrete bridgebeams using FRP sheetsrdquo Construction and Building Ma-terials vol 27 no 1 pp 490ndash520 2012

[181] R El-Hacha and F Oudah ldquoPostfatigue monotonic behaviorof RC beams strengthened with prestressed NSM CFRPstrips ductility evaluationrdquo Journal of Composites for Con-struction vol 18 2013

[182] A A Mufti J P Newhook and G Tadros ldquoDeformabilityversus ductility in concrete beams with FRP reinforcementrdquoin Proceedings of the International Conference on AdvancedComposite Materials in Bridges amp Structures MontrealCanada August 1996


the mechanism and failure modes of the reinforced struc-tures to improve the durability and sustainability of theexisting bridge structures

With the application and development of the traditionalreinforcement technology new building materials are pro-duced and new strengthening methods are developed Usingthe fiber-reinforced polymer (FRP) to strengthen the concretestructures is an ideal method at present(e FRP is a new typeof high-performance material that is composed of a fibermaterial and a matrix material mixed in a certain proportionand compounded via a certain process(e fibers are themainstress materials in the FRP and can be divided into long fibersand short fibers Long fibers are mainly used in FRPs forengineering structures (e fiber plays the roles of stiffeningand strengthening and the resin plays the role of bonding thefiber It can provide reinforcement via the shear force betweenthe FRP sheets and the concrete Recently FRP has beenwidely used as a strengthening material in civil and con-struction engineering structures and repair engineering owingto its high strength light weight corrosion resistance andfatigue resistance [10ndash13]With the rapid development of FRPprocessing and molding technology industrial formingprocesses such as pull-extrusion winding resin transfermolding and vacuum import can produce large standardizedFRP components with stable performance providing thebasic conditions for the wide application of FRP bridgesCurrently the FRPs commonly used in engineering structuresare the carbon fiber-reinforced polymer (CFRP) glass fiber-reinforced polymer (GFRP) basalt fiber-reinforced polymer(BFRP) and aramid fiber-reinforced polymer (AFRP)[14ndash17] In structural engineering the main product forms ofFRP include laminates (sheets and plates) bars cables andgrids [18ndash24] (e most common methods for strengtheningusing FRPs are externally bonded (EB) and near-surfacemounted (NSM) reinforcements [25ndash28]

Some researchers investigated the shear and flexuralperformance of reinforced concrete beams strengthenedwith FRP materials and they obtained some remarkablereinforced effect Hawileh et al [29] studied the effect of

externally bonded CFRP sheets on the shear strength ofshear-deficient reinforced concrete beams as attached to thebeamrsquos soffit (ey indicated that the shear strength ofreinforced concrete beams increased 10ndash70 comparingwith the control specimens (ey also found that the flexurallongitudinal reinforcement ratio played a significant role onthe shear strength of reinforced beams (e effects of theratio of longitudinal reinforcement and angle of applicationof CFRP sheets on the shear capacity of reinforced concretebeams with externally bonded CFRP sheets were investi-gated by (amrin and Zaidir [30] (ey showed that theangle of application of CFRP sheets (45deg and 90deg) had almostno effect on the shear capacity of reinforced beams anddifferent ratios of longitudinal reinforcement resulted indifferent failure modes (ree-sided or completely wrappedapplication of CFRP sheets may be necessary to preventpremature debonding failure for beams with higher values ofthe longitudinal reinforcement ratio (ey also studied theshear strength of reinforced concrete beams with NSM bars[31](e results demonstrated that the strengthened methodcan increase the shear capacity of reinforced beams sig-nificantly In the meanwhile Saqan et al [32] indicated thatboth the strengthening methods of bonded CFRP sheets andNSM bars delayed the yielding of the internal steel rein-forcement and resulted in an increase in the flexural strengthand a decrease in stiffness degradation of the reinforcedconcrete frames Hawileh et al [33] studied the contributionof CFRP laminates on the shear strength of reinforcedbeams (e results demonstrated that the external flexuralCFRP laminates can improve the shear strength of rein-forced members as the vertical sides of reinforced membersare not accessible Moreover using U-wrapped and com-pletely wrapped CFRP sheets were two common wrappingconfigurations to improve the shear capacity of exsitingreinforced concrete structures [34] Some concrete beamscannot strengthen with FRP laminates due to the narrowsoffit To overcome this obstacle Salama et al [35] inves-tigated the feasibility of strengthening reinforced concretebeams in flexure by side-bonded CFRP sheets (ey

2004 8 13

(a) (b)

Figure 1 (e damage of traditional asphalt pavement on a steel deck [7]






21 Types of FRPs















Types Width(mm)

Length(mm)

(ickness(mm)



Ultimatestrain ()







(ickness(mm)

Width(mm)



Fracturestrain ()







Nominal area(mm2)




Ultimatestrain ()

CFRPbars

6 3167 2241 71 124 18110 7126 2172 154 124 17313 1267 2068 262 124 167




22 Products of FRP



















(a) (b)




































(a) (b)

(c)


(a) (b)




























(1)

(2) (3) (4)







(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References






































































































































































































21 Types of FRPs















Types Width(mm)

Length(mm)

(ickness(mm)



Ultimatestrain ()







(ickness(mm)

Width(mm)



Fracturestrain ()







Nominal area(mm2)




Ultimatestrain ()

CFRPbars

6 3167 2241 71 124 18110 7126 2172 154 124 17313 1267 2068 262 124 167




22 Products of FRP



















(a) (b)




































(a) (b)

(c)


(a) (b)




























(1)

(2) (3) (4)







(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References











































































































































































































Types Width(mm)

Length(mm)

(ickness(mm)



Ultimatestrain ()







(ickness(mm)

Width(mm)



Fracturestrain ()







Nominal area(mm2)




Ultimatestrain ()

CFRPbars

6 3167 2241 71 124 18110 7126 2172 154 124 17313 1267 2068 262 124 167




22 Products of FRP



















(a) (b)




































(a) (b)

(c)


(a) (b)




























(1)

(2) (3) (4)







(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References




































































































































































































22 Products of FRP



















(a) (b)




































(a) (b)

(c)


(a) (b)




























(1)

(2) (3) (4)







(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References










































































































































































































(a) (b)




































(a) (b)

(c)


(a) (b)




























(1)

(2) (3) (4)







(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References



































































































































































































































(a) (b)

(c)


(a) (b)




























(1)

(2) (3) (4)







(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References



























































































































































































































(1)

(2) (3) (4)







(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References






































































































































































































(a) (b)


(a) (b)














PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References













































































































































































































PC andT 0427βpβ1

fc

1113969

bfLe

βp

2 minus bf1113872 1113873bc

1 + bf1113872 1113873bc

11139741113972

Le

Eftf

fc

1113968

1113971

β1

1 LgeLe

sinπL

2Le

LltLe

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)



PEBROG βgPC andT

βg fminus033c Eftf1113872 1113873


2g + 01hg + 004bg1113872 1113873

(2)





λΔ ΔuΔy

(3)



λw Wu

Wy

(4)




J SJDJ Mu

Mc

emptyu

emptyc

(5)




5 Conclusions










Acknowledgments


References


































































































































































































5 Conclusions










Acknowledgments


References


































































































































































































review article - hindawi

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