experimental study on flexural behavior of prestressed...

Research ArticleExperimental Study on Flexural Behavior of Prestressed ConcreteBeams Reinforced by CFRP under Chloride Environment

Yunyan Liu and Yingfang Fan

College of Transportation Engineering Dalian Maritime University Dalian 116026 China

Correspondence should be addressed to Yingfang Fan fanyf72aliyuncom

Received 5 May 2019 Revised 15 July 2019 Accepted 24 July 2019 Published 29 August 2019

Guest Editor Charis Apostolopoulos

Copyright copy 2019 Yunyan Liu and Yingfang Fan +is is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in anymedium provided the original work isproperly cited

In order to study the effects of initial damages CFRP reinforcement and chloride corrosion on the flexural behavior of prestressedconcrete beams ten prestressed concrete beams were designed and manufactured which were preloaded with 0 40 and 60of the ultimate load to crack +en part of the beams were reinforced by CFRP and immersed in chloride condition for 120 daysAfter that the four-point bending tests were performed +en the sectional strain deformation flexural stiffness flexuralcapacity ductility and the cracking characteristics were researched +e test results demonstrate that the sectional strain of PCbeams still follows the plane cross section assumption after a pure bending deformation considering of the initial cracks chloridecorrosion and CFRP reinforcement +e initial damage accelerates the chloride corrosion resulting in the loss of initial stiffnessductility and cracking load and the reduction in flexural capacity is less than 10 and the failure modes of these beams are proneto change from concrete crushing to shear failure In the cracking stage the reinforcement of CFRP inhibits the bendingdeformation leading to the reduction in stiffness degradation rates and the increase of cracking load and the ultimate loadincreases by 128sim187 +e reinforcement of CFRP constrains the development of cracks increases the cracks numbers by50sim130 decreases the cracking rates of beam bottoms by 525 and reduces the average crack widths by 658 at 195 kN Itcan be seen that the reinforcing effect of CFRP is more significant compared with the weakening effect of short-term chloridecorrosion and initial damage on the flexural behavior

1 Introduction

Prestressed concrete structure has been widely promotedbecause of its high strength excellent performance andstructure diversification Also these structures are moreprone to be affected by the environment due to its com-position and mechanical characteristics such as high tem-perature freezing acid rain and deicing salt corrosionChloride corrosion is the major influencing factor Nowa-days the durability problems of these structures occurfrequently which needs to be replaced repaired andstrengthened +e Sorell Causeway Bridge [1] in Australiawas demolished and the ldquoSStefanordquo viaduct [2] in Italycollapsed suddenly following the corrosion of prestressingtendons in the beams due to the long-term exposure to anaggressive marine environment Prestressing steel subjected

to high permanent stress has generally poor resistance tocorrosion [3] compared to the ordinary steel bar +e loss ofcross area and mechanical behavior of steel strands and thedegradation of bond behavior between concrete and steelstrands [4ndash6] will have a significant influence on the safety ofprestressed concrete structures Li and Yuan [7] believedthat the effect of slight corrosion rates (less than 287) isnot significant to the flexural capacity but will lead to theremarkable degradation of ultimate deflection for the beamswith wire rupture failure +e tests of Rinaldi et al [8] andZhang et al [9] show that the ultimate capacity of PC beamsdecreases with the increase of corrosion degree and turns thefailure mode from ductile to brittle An analysis model isproposed byWang et al [5] to predict the failure and flexuralstrength of PC beams under chloride corrosion condition Anumerical model is proposed by Coronelli to simulate the

HindawiAdvances in Civil EngineeringVolume 2019 Article ID 2424518 14 pageshttpsdoiorg10115520192424518

effects of wire breaking in PC beams suffering from cor-rosion condition Also the local fracture of corroded steelstrand in different locations in PC beam is simulated byYang et al [10] through a rapid corrosion test and the testresults show that the closer the corrosion fracture location isto the midspan the more obvious the reduction in flexuralstiffness and capacity is

In practical engineering the bridge is not only affectedby the environment but also by fatigue loads Some factorslike low design standards overloaded for a long time or thevehiclesrsquo impact may lead to the damage on concretebridges +e steels in the cracking area are always in a highstress state even if the beam was unloaded completely andthere will be the residual cracks and deflection +e tests ofVicente et al [11] and Recupero and Spinella [12] indicatethat cracking and internal damage caused by cyclic loadingwill affect the bond behavior between steel strand andconcrete reduce the stiffness and natural frequency andincrease the vertical deflection and crack widths +e testsof Dasar et al [13] show that the bending cracks of rein-forced concrete beams exposed to the marine environmentfor a long time accelerate the corrosion rate of the steelreduce the effective prestress and flexural capacity and leadto the earlier failure

Carbon fiber composite (CFRP) has the advantages oflightweight high strength corrosion resistance and fatigueresistance +erefore CFRP is widely used to strength andrepair damaged bridges while greatly reducing installationtime and cost [14] At present the reinforcement of corrodedprestressed concrete structures by CFRP has attracted muchattention Adham and Khaled [15] hold that the flexuralcapacity of corroded prestressed concrete beams can berestored after CFRP repaired but the reduction in ductility isirreversible Shaw and Andrawes [16] repaired a corrodedPC beam by mortar GFRP and CFRP the results show thatthe mortar repair is alone insufficient in regaining theconcrete initial strength and stiffness and CFRP laminatesare superior to GFRP laminates in regaining the stiffness andflexural capacity +e reinforcement of CFRP to prestressedconcrete beams with damages has also been concerned bymany scholars [17ndash20] It is thought that the bearing ca-pacity and stiffness of beams with damages due to overloadand vehicle impact can be effectively restored after the CFRPreinforcement At present there are few research studies onthe CFRP reinforcement of prestressed concrete beams withbending cracks and exposed to chloride environments andsuch damage condition is more close to the actual projectand more worthy to be studied

+e four-point bending tests were applied on all testbeams And the effects of CFRP reinforcement initialbending cracks and chloride corrosion on the distributionof cross-sectional strain structural deformation flexuralstiffness flexural capacity crack propagation and failuremodes were researched

2 Experimental Programs

21 Concrete Specimens Ten pretensioned prestressed con-crete beams were designed and manufactured Commercial

concrete was adopted and the concrete strength grade wasC40 All beams have the same dimension of150times 250times 2200mm +e beams were reinforced by four14mm deformed bars at top and bottom and seven 6mmstirrups with 100mm at beam end +e beams were pre-tensioned with two 127mm strands and the initial prestressof the strand is 558MPa which is about 03 times of the yieldstrength +e details are shown in Figure 1

+e average yield strength of the prestressed strand thedeformed bars and the 6mm plain bars was 1860MPa335MPa and 235MPa respectively and the elastic moduluswas 195GPa 200GPa and 210GPa respectively +e av-erage compressive strength of 28-day concrete for all thebeams was 494MPa

22 Test Condition In order to simulate the influence ofinitial cracks CFRP reinforcement and chloride corrosionon the flexural behavior of PC beams ten beams were ap-plied different loading conditions respectively +e testconditions of all beams are listed in Table 1

In order to simulate the influence of initial damage onthe durability of PC beams six beams were preloaded tocrack with 40 and 60 of the ultimate load +e distri-butions and parameters of initial cracks are shown in Fig-ure 2 and Table 2

+en the beams were reinforced by CFRP andU-shaped hoops were set at both ends such as beam C0-1C40-1 C60-1 C0-2 C40-2 and C60-2 +e reinforcingscheme of CFRP is shown in Figure 3 and the mechanicalproperties of CFRP are shown in Table 3

After preloading and CFRP reinforcement the beamswere immersed in a deicing salt solution for 120 days +ecomponents of the solution are CaCl2 and MgCl2 and theconcentration is 5 It can be seen in Figure 4

23 Loading Process +e actions of multifactor such asinitial damage CFRP reinforcement and chloride corrosionchange the bond performance between steel bars andconcrete and affect the propagation of bending cracks +edesign codes are very difficult to predict the flexural behaviorand crack widths of these PC beams+e four-point bendingtests were employed to study the effects of multifactor on theflexural behavior in the current study Each beamwas simplysupported and had a pure bending span of 600mm and twoshear spans of 600mm Figure 5 shows the details of loadingsetup

+e loading process was divided into two stages+e firststage was controlled by load until reaching 85 of the ul-timate load of the control beam+e load was applied step bystep at a rate of 5 kN per step until crack load then the ratewas 10 kN per step +e second stage was controlled bydeflection and the loading increment was 06mm per step+e loading test was stopped when the carrying capacitydropped to 75 of the ultimate load

+e vertical deflections at the midspan were measured bya displacement sensor Electrical resistance strain gaugeswere pasted on the midspan section to measure concretestrains Arrangement of the gauges is shown in Figure 5 One

2 Advances in Civil Engineering

side of the beam was painted white and was marked with5times 5 cm grids to facilitate the detection of cracks

3 Test Results and Discussion

31 Distribution of Cross-Sectional Strain +e strain dis-tribution curves of PC beams are shown in Figure 6 In theapproximately elastic stage the strains of concrete at dif-ferent heights are small and vary linearly After cracking thestrains increase rapidly And the section in the midspanperpendicular to the beam longitudinal axis is still planeafter a pure bending deformation It is found that thesectional strain at the midspan of the test beams still followsthe plane section assumption after preloading chloridecorrosion and CFRP reinforcement

According to the strain distributions of beams C0-3C40-3 C60-3 C0-2 C40-2 and C60-2 it can be seen thatafter the immersion in chlorine salt for 120 d the steel barswere corroded and expanded resulting in microcracks in thesurrounding concrete During the loading process thecorrosion microcracks developed rapidly until the straingauge failed And the corrosion microcracks in the beamwith the initial damage cracked earlier under the loadingprocess At the same time CFRP pasted on the bottom haslittle effect on chloride corrosion

It can be seen from Figure 6 that the ultimate com-pressive strain of control beam A1 and CFRP reinforcedbeams C0-1 C40-1 and C60-1 which are under naturalconditions is about 0002 +e ultimate compressive strainof CFRP reinforced beams C0-2 C40-2 and C60-2 inchloride condition is about 0002 And the ultimate com-pressive strain of beams C0-3 C40-3 and C60-3 is about0001 It follows that the ultimate strain of concrete decreaseswith the corrosion of steel in the beam and the

3535

7Φ6100

2Φs127

2200

2Φ14

2Φ14 80

45

80170

35180

35Figure 1 Beam details (unit mm)

Table 1 Test conditions

Beam Preloading (kN) Reinforcement Environment conditionA1 0 mdash mdashC0-3 0

mdash Chloride corrosion for 120 dC40-3 85C60-3 125C0-1 0

CFRP reinforcement mdashC40-1 85C60-1 125C0-2 0

CFRP reinforcement Chloride corrosion for 120 dC40-2 85C60-2 125

C40-1

C40-2

C40-3

C60-1

C60-2

C60-3

Figure 2 Initial cracks on the PC beams after preloading

Advances in Civil Engineering 3

reinforcement of CFRP decreases the effect of corrosion onthe ultimate strain Also the relationship between the re-duction of strain and corrosion and CFRP reinforcementremains to be studied

With the increase of load grades the neutral axis movedup from the middle of the beam After cracking themovement increases and the height of the compression zonedecreases gradually +e compressive concrete depths ofeach PC beam under the ultimate load are shown in Figure 7Under natural condition the compressive concrete depth ofthe CFRP reinforced beam is higher than that of the controlbeam and that of each beam decreased compared with thatof the control beam under chloride corrosion for 120 d Alsothe compressive concrete depths of beams C0-1 C40-1 C60-1 C0-3 C40-3 and C60-3 decrease with the increase of theinitial damage degree while the law of C0-2 C40-2 andC60-2 is not obvious

+e chloride condition leads to the corrosion of the steelstrand As the corrosion degree increases the sectional area

of the steel strand decreases +e experiment in the literature[21] indicates that the corroded steel strand is more prone toslip during the bending test and the slip rate and ultimateslip value increase with the corrosion degree +e bond slipbetween the steel strand and the concrete has occurredduring the preloading process +erefore the bond per-formance between the steel strand and concrete has beenweakened after preloaded to crack or corroded by chloridecondition And the tension stress of the steel strand de-creased than that in the control beam under same load gradeFor the CFRP reinforced beam the section curvature and thearm of force between steel bars steel strand CFRP andcompressive concrete are smaller than those of the controlbeam under the action of equivalent load It makes theneutral axis height lower than the control beam and thecompressive concrete depth higher than the control beamAlso the section curvature and the arm of force decreasewith the increase of damage and corrosion degree Due tothe limited data and errors the distribution of cross-sec-tional strains of PC beams and the variation in the com-pressive concrete depths under the action of multifactor arestill to be studied

32 Flexural Behavior

321 Load-Deflection Curves According to the test resultsthe load-deflection curve of PC beams in the midspan isdrawn as shown in Figure 8 With the increase of load gradethe deflection in the midspan goes through three stages

(1) In the approximate elastic stage the deformation ofthe PC beam behaves linearly and slowly Howeverthe initial flexural stiffness of the beams decreaseswith initial damage so the deformation rates of thesebeams in this stage are higher than that of the controlbeam After chloride corrosion of 120 d the stiffnessof the beams decreases further and the deformationrates increase further than that of the control beam

(2) In the cracking stage the bottom concrete wasloaded to crack and exited the work CFRP gives play

Table 2 Parameters of initial cracks on the midspan

Beam Crack number in midspan Space (mm) Sum of cracks (mm) Crack width at bottom Crack height (mm)C40-1 4 150 6 004 40C40-2 3 200 4 006 45C40-3 3 170 6 006 50C60-1 8 80 12 012 130C60-2 7 100 11 012 125C60-3 8 80 11 015 137

200

U-shaped hoopCFRP

1500150 150 200

Figure 3 Reinforcing scheme of CFRP (unit mm)

Table 3 Mechanical properties of CFRP

Material CFRPStandard value of tensile strength 34935MPaElasticity modulus 240GPaElongation 17Bending strength 7375MPaShear strength 487MPaPositive tensile bond strength 36MPa

Figure 4 Deicing salt corrosion


to its high tensile strength so that the stiffnessdegradation rate and the deformation rate of CFRPstrengthened beam decrease Under natural condi-tions the initial damage has little effect on theflexural stiffness however the coupling of chloridecorrosion and initial damage reduces the stiffnessand accelerates the deformation of the structure inthis stage

(3) In the failure stage the test beams yield andmaintaina high bearing capacity and the deflection in themidspan increases rapidly Arriving at the ultimatebearing capacity the structure is destroyed

322 Flexural Stiffness In order to analyze the degradationof the flexural stiffness of PC beams under different workingconditions all test beams are considered as homogeneouselastic material models As the loading time is short and thedeflections along the longitudinal sections are different sothe ldquominimum stiffness principlerdquo is adopted For themembers under flexural load the deflection is obtained byquadratic integration of curvature

w B 1ρ

1113888 1113889x

dx2

BMx

Bsdx

2 (1)

where w is the deflection ρ is the radius of curvature Mx isthe bending moment of the beam plane and Bs is the short-term stiffness +e midspan deflection of the test beam isobtained by solving the above integral +e test beam issimply supported by static loading at two points +e short-term stiffness of the test beam can be obtained by trans-forming the formula (1) as shown in the following formula

Bs SMxl

2o1113872 1113873

f S

Pl3o6f

(2)

where S is the deflection coefficient related to the supportingcondition and load form through calculation the value of Sis 23216 P is the load value f is the deflection in themidspan and lo is the calculated span

According to formula (2) the short-term stiffness of themidspan section is calculated as shown in Figure 9 Before

cracking the flexural stiffness of the test beams is basicallyunchanged and the initial stiffness of the nondestructivebeams C0-1 C0-2 and C0-3 is close to that of the controlbeam Under the chloride condition the initial flexuralstiffness of beams C40-3 and C60-3 with initial cracks de-creases by about 325 and 478 compared with thecontrol beam and that of the CFRP reinforced beams C40-2and C60-2 decreases by about 441 and 397 respectivelyUnder the natural conditions the initial stiffness of theCFRP reinforced beams C40-1 and C60-1 decreases by about128 and 204 respectively compared with the controlbeam After cracking the stiffness of the test beams decreaseswith the increase of load grade Moreover the degradationrates of the stiffness of CFRP reinforced beam are lower thanthat of the control beam

It can be seen that the change rule of the stiffness of thetest beams is consistent with that of the deflection in themidspan +e initial flexural stiffness of the test beams isdecreased due to the initial cracks After the chloride cor-rosion the cross-sectional areas of the internal steel bars andstrands are decreased the bond behaviors between the steelstrand and concrete are weakened and the effective prestressis decreased accordingly +erefore the flexural stiffness ofthe test beams decreases with the increase of damage degreeunder the same load grade After strengthened by CFRPCFRP exerts its high tensile performance in the crackingstage and inhibits the structural deformation and thedegradation rates of the flexural stiffness of the CFRPreinforced beams are reduced compared with the controlbeam However CFRP reinforcement has little effect on theinitial flexural stiffness

323 Cracking Load and Ultimate Load +e effectiveprestress of the PC beam is calculated according to thecracking load of midspan concrete as shown in Table 4 Itcan be seen that the effective prestress and cracking load ofcontrol beamA1 are similar to the theoretical value It can beconsidered that there is no sustained loss of effective pre-stress since the end of the curing period However afterchloride corrosion of 120 d the effective prestress of beamC0-3 decreased by 20 compared with the theoretical value

2

1

4

5

8

200 200600 600 600

2200

6

3

6

7

Figure 5 Loading test setup (unit mm) Note 1 load cell 2 steel spreader beam 3 strain gauge 4 displacement sensor 5 dial indicator6 computer 7 data acquisition system


0

50

100

150

200

250

ndash2000 ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

83

1020304050

60708090100

205170180190200

160110120130140150

(a)

0

50

100

150

200

250

ndash2000 ndash1000 0 1000 2000 3000 4000 5000Strain (με)

Hei

ght (

mm

)

105

1020304050

60708090100

220230240

210170180190200

160110120130140150

(b)

1020304050

90100

607080

210220230235

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

98

(c)

0

50

100

150

200

250


Hei

ght (

mm

)

85

1020304050

60708090100

220230240

210

244

170180190200

160110120130140150

(d)

Figure 6 Continued


1020304050

90100

607080

210170180190200

160110120130140150

0

50

100

150

200

250

ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

81

(e)

1020304050

90100

607080

170180190200

160110120130140150

0

50

100

150

200

250

ndash2000 ndash1000 0 1000 2000Strain (με)

Hei

ght (

mm

)

79

(f )

0

50

100

150

200

250


Hei

ght (

mm

)

75

1020304050

90100

607080

160110120130140150

(g)

0

50

100

150

200

250


Hei

ght (

mm

)

77

1020304050

60708090100

220230

210170180190200

160110120130140150

(h)

Figure 6 Continued


and the cracking load decreased by 14 It shows that thechloride corrosion on the steel strand leads to the degra-dation of its bond behavior with concrete

+e flexural behaviors of the test beams under thevarious working conditions are shown in Table 5 +ecracking load of the test beams decreased after chloridecorrosion and increased after the CFRP reinforcementcompared with that of the control beams

After chloride corrosion of 120 d the ultimate loads ofbeams C0-3 C40-3 and C60-3 were reduced by 12 24and 90 respectively compared with the control beam A1When the initial damage degree is low the weakening effectof short-term chloride corrosion on the flexural behavior isnot obvious and the weakening effect increases with theinitial damage degree Under natural conditions the ulti-mate loads of the CFRP reinforced beams were increased by150sim187 Under chloride condition the ultimate loadsof the CFRP reinforced beams were increased by 128sim162 Chloride corrosion reduces the flexural capacityslightly It is considered that the strengthening effect ofCFRP significantly increases the flexural capacity while thechloride corrosion and initial damage weaken the flexuralbehavior When the three factors are coupled thestrengthening effect of CFRP is dominant compared with theweakening effect of chloride corrosion and initial damage

324 Ductility As can be seen from Table 5 CFRP pastedon the beam bottom exerts its high tensile strength to re-strain the bending deformation and ultimate deflectiondecreases +erefore the ductility of the CFRP reinforcedbeam decreases Under the chloride condition the structurewith initial damage is more likely to be corroded by chlorideresulting in early failure of the structure +erefore theultimate deflection and ductility are reduced significantly

CFRP reinforcement can inhibit the structural de-formation but not reduce the chloride corrosion +erefore

1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)

Figure 6 Distribution of strain at the midspan (a) BeamA1 (b) beamC0-1 (c) beamC40-1 (d) beamC60-1 (e) beamC0-3 (f ) beamC40-3 (g) beam C60-3 (h) beam B2 (i) beam C40-2 and (j) beam C60-2

A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam

CFRP R-beams innatural condition

Beams in chloridecondition

Figure 7 Compressive concrete depths at midspan


the ultimate deflection and ductility of the CFRP reinforcedbeams in chloride condition are further reduced than thoseof the control beams and slightly larger than those of un-reinforced beams

Due to the limited data the changes in flexural capacityand ductility under the coupling of multiple factors still needto be further studied

33 Cracking and Failure

331 Crack Patterns During the loading process newcracks appeared firstly in the middle span and below theloading points of the test beams +e cracks in the purebending span developed vertically upward with the increaseof load steps When the neutral axis reached to the maxi-mum height the cracks are no longer continued +en theoblique cracks in the shear spans extended rapidly +e

distribution maps of cracks are shown in Figure 10 +eparameters of cracks in the pure bending span are shown inTable 6

During the cracking stage initial cracks CFRP re-inforcement and chloride corrosion all have impacts on thecracks of PC beams According to their locations and causesthe cracks in Figure 10 can be divided into three categoriesas is shown in Figure 11

(1) Major cracks caused by bending stress appear in themidspan and below the loading points of the testbeams And the distribution of major cracks depends

0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)

Figure 8 Load-deflection curves

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2

Figure 9 Flexural stiffness


on the comprehensive bonding properties betweenthe steel bar and concrete Corrosion of steel barscaused by chloride leads to microcracks surroundedthe steel bars Bending stress makes the microcrackscontinue to develop and form the second type ofmajor cracks +erefore such cracks occur above thecorroded steel bars

(2) Minor cracks occur near the major cracks +e localbond stress between concrete and CFRP increases

with the increases of load When the local tensilestress of concrete between major cracks reaches theultimate tensile strength the minor cracks appearbetween major cracks Due to the low influenceheight of bond stress such cracks are relatively short

(3) CFRP peeling cracks are the third kind of cracksArriving at the ultimate load there has a tendency oflocal peeling between the CFRP and concrete at thebeam bottoms and the peeling cracks are short andinclined or even parallel to the bottom surface andintersect with the major cracks and then cause thepeeling off of the CFRP and concrete

332 Failure Modes +e failure modes of the test beams areshown in Figure 12 In the bending test the major cracks inthe pure bending span of the control beam are verticallyupward and evenly distributed with the increase of loadgrade When the ultimate load is reached the concretebeams A1 C0-1 C40-1 C60-1 and C40-2 are crushed

Under the chloride condition the crack patterns and thenumbers of unreinforced beams C0-3 C40-3 and C60-3 aresimilar to that of the control beam and part of the majorcracks are developed from the position where the steel barsor strand was corroded In addition the reduction in thecross-sectional area of the steel bars and stirrups leads to theweakening of shear capacity Arriving at the ultimate loadthe oblique cracks are penetrated from the support to theloading point leading to the concrete crushing at the loadingpoint and the compressive strength of the concrete on themidspan was not fully utilized And the structure is subjectedto shear failure

Compared with the control beam the surface cracks inthe CFRP reinforced beams are denser and there are moreshort minor cracks and peeling cracks For example undernatural conditions the crack numbers of the CFRP rein-forced beams in the midspan are about 17sim23 times that of

Table 4 +e effective prestress

PC beam Cracking load (kN) Effective prestress (kN)+eoretical value 703 10329Control beam A1 700 10294Beam C0-3 600 8278

Table 5 Summary of the results

No Rebound strength(MPa)

Crackingload (kN)

Ultimateload (kN)

Ultimatedeflection (mm) Yield load (kN) Yield

deflection (mm) Ductility factor

A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220

Figure 10 Distribution maps of cracks


the control beam and under chloride environment thecrack numbers of the CFRP reinforced beams in the mid-span are about 15sim2 times that of the control beam A1Arriving at the ultimate load the concrete of the CFRPreinforced beams in the midspan or under the loading pointare crushed and CFRP is fractured and peeled off In thisexperiment the damage on CFRP is not serious which can

prevent the concrete from disintegrated and falling off on alarge scale

333 Crack Widths +e average widths of the major crackson different heights of PC beams are shown in Figure 8 Itcan be seen that the crack widths shift linearly with the

Table 6 Parameters of cracks in the pure bending span

Beam Number Average spacing (mm) Height (mm) Maximum width (mm) Crack patterns Failure modeA1 7 91 170 018 MAC CCFC0-1 15 45 150 012

MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024

MAC CCF CSFC60-3 8 77 160 022C40-3 9 74 155 020NoteMAC major crack MIC minor crack PEC CFRP peeling crack CCF concrete crush failure CSF concrete shear failure CRF CFRP rupture failure

Minor

cracks

Peeling

cracks

Major

cracks

Figure 11 Classification of cracks

C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3

Figure 12 Failure modes of the test beams


increase of load steps +e average widths of cracks onbottoms of CFRP strengthened beams C0-1 C0-2 C40-1C40-2 C60-1 and C60-2 are all significantly smaller thanthat of the unreinforced beams A1 C0-3 C40-3 and C60-3+e cracking widths of the CFRP reinforced beams areslightly smaller than that of the unreinforced beams at aheight of 5 cm from the beam bottom At a height of 10 cmfrom the beam bottom the gaps of the crack widths betweenthe CFRP reinforced beams and the unreinforced beams arenot obvious

As can be seen from Figure 13 the reinforcement of CFRPhas a greater impact on the development of cracks comparedwith initial damage and short-term chloride corrosion+erefore the average crack widths of CFRP reinforced andunreinforced beams were fitted with the linear methodWhenthe load is 115 kN the average crack widths of the CFRPreinforced beams at 0 cm 5 cm and 10 cm from the beambottom decrease by 29 11 and 5 respectively com-pared with that of the unreinforced beams When the load is195 kN they decrease by 525 325 and 175 re-spectively At the same time the average crack widths of theunreinforced beams at 5 cm and 10 cm are 311 and 563smaller than those at the bottom while the average crackwidths of the CFRP reinforced beams at 5 cm and 10 cm areonly 31 and 24 smaller than those at the bottom

+e cracking rates of the test beams are shown in Fig-ure 14 +e cracking rates of unreinforced beam graduallydecrease with the increase of cracking heights For examplethe cracking rate at the beam bottom is 125 μmkm and thecracking rate at 5 cm and 10 cm decreased by 364 and710 respectively +e cracking rates of the CFRP rein-forced beams at 0 cm 5 cm and 10 cm are almost same andthe cracking rates are 658 457 and 267 lower thanthat of the unreinforced beams respectively

In conclusion the average crack widths and cracking ratesof the CFRP reinforced beams at the same heights are alwayssmaller than those of the unreinforced beams and the gapsbetween them increase with the load steps and decrease withthe increase of crack heights Initial damage and short-term

chloride corrosion have no obvious effects on the process ofcracking However CFRP has a significant constraint on thedevelopment of cracks and the effect decreases with theincrease of crack heights Also the influence height of con-straint is related to the thickness layer numbers of CFRP andother factors which need to be further studied

4 Conclusions

Ten pretensioned concrete beams designed with differenttest conditions were tested And the effects of initial cracksCFRP reinforcement and chloride corrosion on the flexuralbehavior cracking characteristics and failure modes werediscussed +e following conclusions can be drawn based onthe test

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3

Average valueof PC Beam

Average value of CFRPreinforced beam

(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3

Average valueof PC beam


(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)

Figure 13 Crack widths and loads curves (a) Average widths of cracks on the bottom (b) at 5 cm and (c) at 10 cm

0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)

Figure 14 Cracking rates


(1) Considering the initial cracks chloride corrosionand CFRP reinforcement the sectional strain of thetest beams still follows the plane section assumptionafter a pure bending deformation

(2) +e initial flexural stiffness is reduced by initialcracks and chloride corrosion and CFRP re-inforcement has little effect on the initial flexuralstiffness Before cracking the flexural stiffness of thetest beams is basically unchanged with the load stepsIn the cracking stage the stiffness decreases with theincrease of load steps And CFRP pasted on the beambottom exerts its high tensile performance in thisstage inhibits the structural deformation and re-duces the degradation rate of flexural stiffnesscompared with the control beam

(3) +e effect of chloride corrosion increases with thedegree of initial cracks Under the chloride conditionof 120 d the effective prestress of the PC beams isweakened cracking loads and ductility are reducedand the ultimate loads are reduced by less than 10And the failure mode is prone to change fromconcrete crushing failure to shear failure After thereinforcement of CFRP the cracking loads of the testbeams increase the ductility of these beams is re-duced compared to the control beam and increasedcompared to the chloride corrosion beams and theultimate loads increase than the control beam by128sim187 When the three factors are coupledthe enhancement effect of CFRP is more obviousthan the weakening effects of short-term chloridecorrosion and initial damage

(4) CFRP reinforcement has a constraint effect on thedevelopment of cracks and the effect decreases withthe increases of crack height +erefore the averagecrack width and cracking rate of the CFRP reinforcedbeams at the same height are always smaller thanthose of the unreinforced beams When the loadgrade is 195 kN the average crack widths of theCFRP reinforced beams at 0 cm 5 cm and 10 cmfrom the beam bottom are 525 325 and 175smaller than that of the unreinforced beams and thecracking rates are reduced by 658 457 and267 respectively

Data Availability

+e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

+e authors declare that they have no conflicts of interest

Acknowledgments

+is work was conducted with the financial support fromthe National Natural Science Foundation of China (grantnos 51578099 and 51178069) +e support is gratefullyacknowledged

References

[1] M P Torill and R E Melchers ldquoPerformance of 45-year-oldcorroded prestressed concrete beamsrdquo Structures andBuildings vol 166 pp 547ndash559 2013

[2] P Colajanni A Recupero G Ricciardi and N SpinellaldquoFailure by corrosion in PC bridges a case history of a viaductin Italyrdquo International Journal of Structural Integrity vol 7no 2 pp 181ndash193 2016

[3] F Li Y Yuan and C-Q Li ldquoCorrosion propagation ofprestressing steel strands in concrete subject to chloride at-tackrdquo Construction and Building Materials vol 25 no 10pp 3878ndash3885 2011

[4] L Wang X Zhang J Zhang J Yi and Y Liu ldquoSimplifiedmodel for corrosion-induced bond degradation between steelstrand and concreterdquo Journal of Materials in Civil Engi-neering vol 29 no 4 article 04016257 2017

[5] L Wang X Zhang J Zhang L Dai and Y Liu ldquoFailureanalysis of corroded PC beams under flexural load consid-ering bond degradationrdquo Engineering Failure Analysis vol 73pp 11ndash24 2017

[6] F Li and Y Yuan ldquoEffects of corrosion on bond behaviorbetween steel strand and concreterdquo Construction and BuildingMaterials vol 38 pp 413ndash422 2013

[7] F-M Li and Y-S Yuan ldquoExperimental study on bendingproperty of prestressed concrete beams with corroded steelstrandsrdquo Journal of Building Structures vol 31 no 2pp 78ndash84 2010

[8] Z Rinaldi S Imperatore and C Valente ldquoExperimentalevaluation of the flexural behavior of corroded PC beamsrdquoConstruction and Building Materials vol 24 no 11pp 2267ndash2278 2010

[9] X Zhang L Wang J Zhang Y Ma and Y Liu ldquoFlexuralbehavior of bonded post-tensioned concrete beams understrand corrosionrdquo Nuclear Engineering and Design vol 313pp 414ndash424 2017

[10] R Yang J Zhang L Wang et al ldquoExperimental research forflexural behavior on concrete beams with local corrosionfracture of strandsrdquo Journal of Central South University(Science and Technology) vol 49 no 10 pp 2593ndash2601 2018

[11] M A Vicente D C Gonzalez and J A Martınez ldquoMechanicalresponse of partially prestressed precast concrete I-beams afterhigh-range cyclic loadingrdquo Practice Periodical on StructuralDesign and Construction vol 20 no 1 pp 1ndash22 2015

[12] A Recupero and N Spinella ldquoPreliminary results of flexuraltests on corroded prestressed concrete beamsrdquo in Proceedingsof the Fib Symposium 2019 CONCRETE-Innovations inMaterials Design and Structures pp 1323ndash1330 KrakowPoland May 2019

[13] A Dasar R Irmawaty H Hamada Y Sagawa andD Yamamoto ldquoPrestress loss and bending capacity of pre-cracked 40 year-old PC beams exposed to marine environ-mentrdquoMatec WEB of Conferences vol 47 article 02008 2016

[14] N Spinella P Colajanni A Recupero and F TondololdquoUltimate shear of RC beams with corroded stirrups andstrengthened with FRPrdquo Buildings vol 9 no 2 p 34 2019

[15] E M Adham and S Khaled ldquoFlexural behavior of corrodedpretensioned girders repaired with CFRP sheetsrdquo PCI Journalvol 59 no 2 pp 129ndash143 2014

[16] I Shaw and B Andrawes ldquoRepair of damaged end regions ofPC beams using externally bonded FRP shear reinforcementrdquoConstruction and Building Materials vol 148 pp 184ndash1942017


[17] L K Jarret K A Harries R Miller and R J BrinkmanldquoRepair of prestressed-concrete girders combining internalstrand splicing and externally bonded CFRP techniquesrdquoJournal of Bridge Engineering vol 19 no 2 pp 200ndash209 2014

[18] E R Calvin and R J Peterman ldquoEvaluation of prestressedconcrete girders strengthened with carbon fiber reinforcedpolymer sheetsrdquo Journal of Bridge Engineering vol 9 no 2pp 185ndash192 2004

[19] D Cerullo K Sennah H Azimi C Lam A Fam andB +armabala ldquoExperimental study on full-scale preten-sioned bridge girder damaged by vehicle impact and repairedwith fiber-reinforced polymer technologyrdquo Journal of Com-posites for Construction vol 17 no 5 pp 662ndash672 2013

[20] A Elsafty M K Graeff and S Fallaha ldquoBehavior of laterallydamaged prestressed concrete bridge girders repaired withCFRP laminates under static and fatigue loadingrdquo In-ternational Journal of Concrete Structures and Materialsvol 8 no 1 pp 43ndash59 2014

[21] Y Liu Y Fan J Yu et al ldquoFlexural behavior test of corrodedprestressed concrete beams under chloride environmentrdquoActa Materiae Compositae Sinica no 37 In press in Chinese


International Journal of

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Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

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Control Scienceand Engineering

Journal of



Journal ofEngineeringVolume 2018

SensorsJournal of



RotatingMachinery


Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018


Chemical EngineeringInternational Journal of Antennas and

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Navigation and Observation


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wwwhindawicom Volume 2018

Advances in

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Submit your manuscripts atwwwhindawicom

effects of wire breaking in PC beams suffering from cor-rosion condition Also the local fracture of corroded steelstrand in different locations in PC beam is simulated byYang et al [10] through a rapid corrosion test and the testresults show that the closer the corrosion fracture location isto the midspan the more obvious the reduction in flexuralstiffness and capacity is

In practical engineering the bridge is not only affectedby the environment but also by fatigue loads Some factorslike low design standards overloaded for a long time or thevehiclesrsquo impact may lead to the damage on concretebridges +e steels in the cracking area are always in a highstress state even if the beam was unloaded completely andthere will be the residual cracks and deflection +e tests ofVicente et al [11] and Recupero and Spinella [12] indicatethat cracking and internal damage caused by cyclic loadingwill affect the bond behavior between steel strand andconcrete reduce the stiffness and natural frequency andincrease the vertical deflection and crack widths +e testsof Dasar et al [13] show that the bending cracks of rein-forced concrete beams exposed to the marine environmentfor a long time accelerate the corrosion rate of the steelreduce the effective prestress and flexural capacity and leadto the earlier failure

Carbon fiber composite (CFRP) has the advantages oflightweight high strength corrosion resistance and fatigueresistance +erefore CFRP is widely used to strength andrepair damaged bridges while greatly reducing installationtime and cost [14] At present the reinforcement of corrodedprestressed concrete structures by CFRP has attracted muchattention Adham and Khaled [15] hold that the flexuralcapacity of corroded prestressed concrete beams can berestored after CFRP repaired but the reduction in ductility isirreversible Shaw and Andrawes [16] repaired a corrodedPC beam by mortar GFRP and CFRP the results show thatthe mortar repair is alone insufficient in regaining theconcrete initial strength and stiffness and CFRP laminatesare superior to GFRP laminates in regaining the stiffness andflexural capacity +e reinforcement of CFRP to prestressedconcrete beams with damages has also been concerned bymany scholars [17ndash20] It is thought that the bearing ca-pacity and stiffness of beams with damages due to overloadand vehicle impact can be effectively restored after the CFRPreinforcement At present there are few research studies onthe CFRP reinforcement of prestressed concrete beams withbending cracks and exposed to chloride environments andsuch damage condition is more close to the actual projectand more worthy to be studied

+e four-point bending tests were applied on all testbeams And the effects of CFRP reinforcement initialbending cracks and chloride corrosion on the distributionof cross-sectional strain structural deformation flexuralstiffness flexural capacity crack propagation and failuremodes were researched

2 Experimental Programs

21 Concrete Specimens Ten pretensioned prestressed con-crete beams were designed and manufactured Commercial

concrete was adopted and the concrete strength grade wasC40 All beams have the same dimension of150times 250times 2200mm +e beams were reinforced by four14mm deformed bars at top and bottom and seven 6mmstirrups with 100mm at beam end +e beams were pre-tensioned with two 127mm strands and the initial prestressof the strand is 558MPa which is about 03 times of the yieldstrength +e details are shown in Figure 1

+e average yield strength of the prestressed strand thedeformed bars and the 6mm plain bars was 1860MPa335MPa and 235MPa respectively and the elastic moduluswas 195GPa 200GPa and 210GPa respectively +e av-erage compressive strength of 28-day concrete for all thebeams was 494MPa

22 Test Condition In order to simulate the influence ofinitial cracks CFRP reinforcement and chloride corrosionon the flexural behavior of PC beams ten beams were ap-plied different loading conditions respectively +e testconditions of all beams are listed in Table 1

In order to simulate the influence of initial damage onthe durability of PC beams six beams were preloaded tocrack with 40 and 60 of the ultimate load +e distri-butions and parameters of initial cracks are shown in Fig-ure 2 and Table 2

+en the beams were reinforced by CFRP andU-shaped hoops were set at both ends such as beam C0-1C40-1 C60-1 C0-2 C40-2 and C60-2 +e reinforcingscheme of CFRP is shown in Figure 3 and the mechanicalproperties of CFRP are shown in Table 3

After preloading and CFRP reinforcement the beamswere immersed in a deicing salt solution for 120 days +ecomponents of the solution are CaCl2 and MgCl2 and theconcentration is 5 It can be seen in Figure 4

23 Loading Process +e actions of multifactor such asinitial damage CFRP reinforcement and chloride corrosionchange the bond performance between steel bars andconcrete and affect the propagation of bending cracks +edesign codes are very difficult to predict the flexural behaviorand crack widths of these PC beams+e four-point bendingtests were employed to study the effects of multifactor on theflexural behavior in the current study Each beamwas simplysupported and had a pure bending span of 600mm and twoshear spans of 600mm Figure 5 shows the details of loadingsetup

+e loading process was divided into two stages+e firststage was controlled by load until reaching 85 of the ul-timate load of the control beam+e load was applied step bystep at a rate of 5 kN per step until crack load then the ratewas 10 kN per step +e second stage was controlled bydeflection and the loading increment was 06mm per step+e loading test was stopped when the carrying capacitydropped to 75 of the ultimate load

+e vertical deflections at the midspan were measured bya displacement sensor Electrical resistance strain gaugeswere pasted on the midspan section to measure concretestrains Arrangement of the gauges is shown in Figure 5 One







3535

7Φ6100

2Φs127

2200

2Φ14

2Φ14 80

45

80170

35180







C40-1

C40-2

C40-3

C60-1

C60-2

C60-3













200

U-shaped hoopCFRP

1500150 150 200









w B 1ρ

1113888 1113889x

dx2

BMx

Bsdx

2 (1)


Bs SMxl

2o1113872 1113873

f S

Pl3o6f

(2)






2

1

4

5

8

200 200600 600 600

2200

6

3

6

7



0

50

100

150

200

250


Hei

ght (

mm

)

83

1020304050

60708090100

205170180190200

160110120130140150

(a)

0

50

100

150

200

250


Hei

ght (

mm

)

105

1020304050

60708090100

220230240

210170180190200

160110120130140150

(b)

1020304050

90100

607080

210220230235

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

98

(c)

0

50

100

150

200

250


Hei

ght (

mm

)

85

1020304050

60708090100

220230240

210

244

170180190200

160110120130140150

(d)

Figure 6 Continued


1020304050

90100

607080

210170180190200

160110120130140150

0

50

100

150

200

250

ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

81

(e)

1020304050

90100

607080

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

79

(f )

0

50

100

150

200

250


Hei

ght (

mm

)

75

1020304050

90100

607080

160110120130140150

(g)

0

50

100

150

200

250


Hei

ght (

mm

)

77

1020304050

60708090100

220230

210170180190200

160110120130140150

(h)

Figure 6 Continued







1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)


A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam












0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia







3535

7Φ6100

2Φs127

2200

2Φ14

2Φ14 80

45

80170

35180







C40-1

C40-2

C40-3

C60-1

C60-2

C60-3













200

U-shaped hoopCFRP

1500150 150 200









w B 1ρ

1113888 1113889x

dx2

BMx

Bsdx

2 (1)


Bs SMxl

2o1113872 1113873

f S

Pl3o6f

(2)






2

1

4

5

8

200 200600 600 600

2200

6

3

6

7



0

50

100

150

200

250


Hei

ght (

mm

)

83

1020304050

60708090100

205170180190200

160110120130140150

(a)

0

50

100

150

200

250


Hei

ght (

mm

)

105

1020304050

60708090100

220230240

210170180190200

160110120130140150

(b)

1020304050

90100

607080

210220230235

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

98

(c)

0

50

100

150

200

250


Hei

ght (

mm

)

85

1020304050

60708090100

220230240

210

244

170180190200

160110120130140150

(d)

Figure 6 Continued


1020304050

90100

607080

210170180190200

160110120130140150

0

50

100

150

200

250

ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

81

(e)

1020304050

90100

607080

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

79

(f )

0

50

100

150

200

250


Hei

ght (

mm

)

75

1020304050

90100

607080

160110120130140150

(g)

0

50

100

150

200

250


Hei

ght (

mm

)

77

1020304050

60708090100

220230

210170180190200

160110120130140150

(h)

Figure 6 Continued







1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)


A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam












0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia












200

U-shaped hoopCFRP

1500150 150 200









w B 1ρ

1113888 1113889x

dx2

BMx

Bsdx

2 (1)


Bs SMxl

2o1113872 1113873

f S

Pl3o6f

(2)






2

1

4

5

8

200 200600 600 600

2200

6

3

6

7



0

50

100

150

200

250


Hei

ght (

mm

)

83

1020304050

60708090100

205170180190200

160110120130140150

(a)

0

50

100

150

200

250


Hei

ght (

mm

)

105

1020304050

60708090100

220230240

210170180190200

160110120130140150

(b)

1020304050

90100

607080

210220230235

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

98

(c)

0

50

100

150

200

250


Hei

ght (

mm

)

85

1020304050

60708090100

220230240

210

244

170180190200

160110120130140150

(d)

Figure 6 Continued


1020304050

90100

607080

210170180190200

160110120130140150

0

50

100

150

200

250

ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

81

(e)

1020304050

90100

607080

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

79

(f )

0

50

100

150

200

250


Hei

ght (

mm

)

75

1020304050

90100

607080

160110120130140150

(g)

0

50

100

150

200

250


Hei

ght (

mm

)

77

1020304050

60708090100

220230

210170180190200

160110120130140150

(h)

Figure 6 Continued







1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)


A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam












0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia





w B 1ρ

1113888 1113889x

dx2

BMx

Bsdx

2 (1)


Bs SMxl

2o1113872 1113873

f S

Pl3o6f

(2)






2

1

4

5

8

200 200600 600 600

2200

6

3

6

7



0

50

100

150

200

250


Hei

ght (

mm

)

83

1020304050

60708090100

205170180190200

160110120130140150

(a)

0

50

100

150

200

250


Hei

ght (

mm

)

105

1020304050

60708090100

220230240

210170180190200

160110120130140150

(b)

1020304050

90100

607080

210220230235

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

98

(c)

0

50

100

150

200

250


Hei

ght (

mm

)

85

1020304050

60708090100

220230240

210

244

170180190200

160110120130140150

(d)

Figure 6 Continued


1020304050

90100

607080

210170180190200

160110120130140150

0

50

100

150

200

250

ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

81

(e)

1020304050

90100

607080

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

79

(f )

0

50

100

150

200

250


Hei

ght (

mm

)

75

1020304050

90100

607080

160110120130140150

(g)

0

50

100

150

200

250


Hei

ght (

mm

)

77

1020304050

60708090100

220230

210170180190200

160110120130140150

(h)

Figure 6 Continued







1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)


A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam












0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia


0

50

100

150

200

250


Hei

ght (

mm

)

83

1020304050

60708090100

205170180190200

160110120130140150

(a)

0

50

100

150

200

250


Hei

ght (

mm

)

105

1020304050

60708090100

220230240

210170180190200

160110120130140150

(b)

1020304050

90100

607080

210220230235

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

98

(c)

0

50

100

150

200

250


Hei

ght (

mm

)

85

1020304050

60708090100

220230240

210

244

170180190200

160110120130140150

(d)

Figure 6 Continued


1020304050

90100

607080

210170180190200

160110120130140150

0

50

100

150

200

250

ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

81

(e)

1020304050

90100

607080

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

79

(f )

0

50

100

150

200

250


Hei

ght (

mm

)

75

1020304050

90100

607080

160110120130140150

(g)

0

50

100

150

200

250


Hei

ght (

mm

)

77

1020304050

60708090100

220230

210170180190200

160110120130140150

(h)

Figure 6 Continued







1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)


A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam












0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia


1020304050

90100

607080

210170180190200

160110120130140150

0

50

100

150

200

250

ndash1000 0 1000 2000 3000Strain (με)

Hei

ght (

mm

)

81

(e)

1020304050

90100

607080

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

79

(f )

0

50

100

150

200

250


Hei

ght (

mm

)

75

1020304050

90100

607080

160110120130140150

(g)

0

50

100

150

200

250


Hei

ght (

mm

)

77

1020304050

60708090100

220230

210170180190200

160110120130140150

(h)

Figure 6 Continued







1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)


A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam












0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia







1020304050

90100

607080

210220230239

170180190200

160110120130140150

0

50

100

150

200

250


Hei

ght (

mm

)

74

(i)

0

50

100

150

200

250


Hei

ght (

mm

)

81

1020304050

60708090100

220210

170180190200

160110120130140150

230

(j)


A1

C0-1

C40-

1

C60-

1

C0-3

C40-

3

C60-

3

C0-2

C40-

2

C60-

2 --

70

80

90

100

110

A1

C0-1

C40-1

C60-1

C0-3 C40-3

C60-3C0-2

C40-2

C60-2

Com

pres

sive c

oncr

ete d

epth

(mm

)

Beam












0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia









0 5 10 15 200

50

100

150

200

250

A1C0-1

C40-1C60-1

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-3

C40-3C60-3

Load

(kN

)

Deflection (mm)

0 5 10 15 200

50

100

150

200

250

A1C0-1C0-2

C60-1C40-2

Load

(kN

)

Deflection (mm)


0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1

C40-1C60-1

0 2 4 6 8A1 (Bs)

0

50

100

150

200

250

A1

(load

kN

)

A1C0-3

C40-3C60-3

0 2 4 6 8Bs(1012N times mm)

0

50

100

150

200

250

Load

(kN

)

A1C0-1C0-2

C40-2C60-2














Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia













Crackingload (kN)

Ultimateload (kN)



A1 495 70 20568 1971 19458 1231 160C0-1 496 80 23928 1892 22002 1253 151C40-1 496 7075 23654 1855 21586 1237 150C60-1 505 7595 24423 1869 22426 1329 141C0-2 498 85 23194 1716 22136 1313 131C40-2 484 7075 23902 1677 22805 1327 126C60-2 511 7575 23698 1711 21965 1468 133C0-3 512 60 20320 1557 18729 1103 141C40-3 502 7050 20070 1484 19098 1190 125C60-3 512 7060 18725 1418 17470 1174 121

C40-1

C0-1

A1

C60-1

C0-2

C20-2

C60-2

C0-3

C40-3

C60-3

0 40 80 110 140 180 220








MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia







MAC MIC PEC

CCF CRFC40-1 16 39 165 028C60-1 12 52 155 025C0-2 12 47 155 012

CCF CRFC60-2 14 42 150 015C40-2 12 52 162 011C0-3 8 80 165 024


Minor

cracks

Peeling

cracks

Major

cracks


C40-1

C60-1

C0-2

A1 1

C0-1

C40-2 C60-2

C0-3 C40-3 C60-3








4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia







4 Conclusions


80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (0cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(a)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (5cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(b)

80 100 120 140 160 180 200000

005

010

015

020

w (m

m)

Load (kN) (10cm)

A1C0-1C0-3C0-2C40-1

C40-2C40-3C60-1C60-2C60-3



(c)


0

4

8

12

16Pr

opag

atio

n ra

te (

10ndash4

mm

kN

)

5

PC beam-0cm

CFRP R-beam-0cm

PC beam-5cm

CFRP R-beam-5cm

PC beam-10cm

CFRP R-beam-10cm

0 10Height (cm)







Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia






Data Availability




Acknowledgments


References


























RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia










RoboticsJournal of




VLSI Design



Shock and Vibration







Journal of



Volume 2018



Volume 2018


Journal of




SensorsJournal of



RotatingMachinery





Propagation






Hindawi


Advances in

Multimedia


experimental study on flexural behavior of prestressed...

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