GroutingDefectDetectionofLappedBarConnections …downloads.hindawi.com/journals/sv/2019/1934240.pdf · 2019-10-14 · condition, including the time-history response and the frequencyresponse,indicatingthattheholeAbehavedasa

Research ArticleGrouting Defect Detection of Lapped Bar ConnectionsBased on Impact-Echo Method

Yun-Lin Liu1 Jing-Jing Shi1 Jun-Qi Huang 23 Guang-Shuo Wei4 and Zhi-Xin Wu4

1School of Civil Engineering Anhui Jianzhu University Hefei 230601 China2School of Civil and Hydraulic Engineering Hefei University of Technology Hefei 230009 China3Department of Civil and Environmental Engineering ampe Hong Kong Polytechnic University Hong Kong China4Anhui Institute of Building Research and Design Hefei 230088 China

Correspondence should be addressed to Jun-Qi Huang junqihuang001163com

Received 20 May 2019 Revised 22 August 2019 Accepted 18 September 2019 Published 14 October 2019

Academic Editor Mohammad Rafiee

Copyright copy 2019 Yun-Lin Liu et al is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Grouted lap-splice connections are widely used for connecting precast concrete components Grouting defects in the connectionssignificantly influence the structural performance of the whole connection which leads to the need for grouting defect detectionIn this study the impact-echo (IE) method was used for detecting defects in grouted lap-splice connections Grouted connectionswith different levels of artificial grout defects were prepared in a shear wall and the IE method was used to measure the frequencyresponse In addition finite element (FE) analysis based on ABAQUS was conducted to simulate the tests Based on the validatedFEmodel a parametric study was conducted to investigate the effect of the depth of the grout hole on the amplitude spectrumeresults indicated that (1) the IEmethod offered a good potential for grouting defect detection in grouted lap-splice connections (2)the proposed FE model could well predict the frequency response of the grouting hole and (3) the measured frequency andamplitude of the grouting hole in an impact-echo test would be considerably influenced by the hole depth

1 Introduction

Grouted lap-splice connections are typical in precast con-crete structures which result in easy construction comparedwith other connecting systems (eg grouted sleeves)Generally during the construction process the connectingsteel bars are inserted into the precast concrete componentsthat need to be connected initially ereafter cement-basedmaterial (ie grout) is injected from the prepared hole (seeldquoGrouting inletrdquo in Figure 1) and the connections areformed after the curing stage Figure 1 shows the details ofthe grouted lap-splice connection

Grouting quality directly affects the structural perfor-mance of the connected elements because it is the key partthat connects two adjacent components together If the groutcontains large voids the existing water and air inside thehole would cause corrosion of the connecting steel barsFurthermore it would influence the structural performanceof the precast concrete components In addition defects inthe grout will lead to stress concentration in the lapped bars

which results in a stress state that is inconsistent with thedesign andmay affect the overall structural safetyereforeit is necessary to develop a method to detect defects ingrouted lap-splice connections

Nondestructive testing (NDT) techniques have beendeveloped to evaluate the material properties and soundnessof concrete elements since 1940s [1] e impact-echo (IE)method is one of the NDT techniques for concrete flawdetection e IE method is based on the propagation andreflection of stress waves induced by a short-duration me-chanical impact [1ndash6] e IE response is related to thematerial property the geometry of the test specimenboundary conditions flaw size and flaw location within thespecimen [1ndash6] Details of the working principle of the IEtesting method are introduced in the following section

In the 1980s the IE method was adopted in the civilengineering field to detect flaws in concrete and masonrystructures [1 2] Sansalone and Streett [2] providedguideline on how to use the IE method in practical engi-neering e IE method has been used successfully to detect

HindawiShock and VibrationVolume 2019 Article ID 1934240 14 pageshttpsdoiorg10115520191934240

flaws in various structural components such as prestressedconcrete slabs [6] reinforced concrete beams and columns[7] concrete blocks [8] epoxy-concrete interface [9] bridgedecks [10] I-girders [11] tunnel linings [12] cavities aroundconcrete sewage pipelines [13] prestressed concrete slabs[14] and grouting of prestressed concrete structuralmembers [15ndash18]

Although research has been conducted in this fieldthere is a lack of information on the application of the IEmethod in defect detection of grouted lap-splice con-nections erefore the objective of this study is to in-vestigate whether the existing IE method could be used todetect grouting defects in grouted lap-splice connectionsof shear walls For this purpose a precast shear wallcontaining grouting holes with a series of artificial defectswas used to investigate the applicability of the IE methode frequency response of the grouted holes with differentdefect levels were determined and compared in detail Inaddition finite element (FE) analyses were conducted tosimulate the test and a parametric study was conducted toinvestigate the effect of hole depth on the frequencyresponse

2 Theory and Test System of the Impact-Echo(IE) Method

21 ampeory of the IE Method e IE method is a NDTtechnique that incorporates the principle of low-frequencytransient stress wave propagation e principle of the IEtechnique is illustrated in Figure 2 in which T is thedistance from the internal defect to the top plate surfaceand ∆t is the time when the P-wave first arrives at the signalreceiving point A small steel ball is used to impact thespecimen surface which generates stress waves thatpropagate through the test specimen ree types of wavesare generated which are named as P- S- and R-waves eP-wave and S-wave are associated with particle motionparallel and perpendicular to the propagation directionrespectively e R-wave (also known as Rayleigh wave) is asurface wave that travels along the solid surface In the IEmethod the measured displacement response is mainly

influenced by the P-wave owing to the close location of thesensor and impact point [1 2] Reflection refraction anddiffraction would occur when these waves encounter in-terfaces between materials with different acousticimpedances

e sensor responds to the arrival of reflected waves andthe recorded time domain signals are transformed into thefrequency domain using the fast Fourier transform (FFT)technique e frequency with peak amplitude in the ob-tained spectrum represents the dominant frequency in thewaveform is dominant frequency also known as thethickness frequency can be estimated as

f βK

n

Vp

T (1)

where K is a geometric correction factor that is determinedby the geometrical shape of the structure [3] n is a constantfactor either equal to 2 or 4 depending on the acousticimpedances [3] β is an empirical correction factor which hasa value of 096 [1 2] or 095 [4 5] andVp is the P-wave speedand is calculated through Vp E(1 minus ])[ρ(1 + ])1113864

(1 minus 2])]05 where E ρ and ] are the elastic modulusdensity and Poissonrsquos ratio of the test object respectively

Precast wall

Lapped rebar in grouting holeFloor

Protruding rebar

Rebar inside precast wall

Spiral stirrup

Protruding rebar

Groutinginlet

Groutingoutlet

Grout

Figure 1 Reinforced mortar anchor lap connection

p-wave

R-wave

Time

Time

ReceiverImpact

Force

Contacttime

Disp

lacement

Δt

T

Figure 2 Principle of the impact-echo method [1]

2 Shock and Vibration

For the precast shear wall in this study K β and n are equalto 10 096 and 20 respectively [1 2]

22 IE Test

221 Introduction An IE test system mainly includes threecomponents a small steel ball a transducer and a waveformanalyzer e frequency content of the stress pulse is gov-erned by the impact contact time andmost of the energy in astress pulse exists in a frequency of 0 to 15tc (tc is thecontact time) With a decrease of the contact time thefrequency range would be increased With shorter contacttimes smaller defects can be discerned and shallower depthscan be measured However the amplitude of each com-ponent frequency would be lowered which decreases thepenetrating ability of the stress waves [2] As the contact timeis a linear function of the ball diameter and has a very weakdependence on the kinetic energy at impact [2] the selectionof the impact source significantly influences the results of anIE test In this study the impactor was a 6mm steel spherewhich has a contact time of approximately 25 μs with theconcrete [2]

222 Application of the IE Test System Whether a void in aslab or wall can be detected mainly depends on its lateraldimensions (l in Figure 3) depth (d in Figure 3) and thecontact time [1] If lgt (14)d the presence of the flaw can bedetected If lgt (13)d the flaw depth can be measured Iflgt 15 d the flaw behaves as an infinite boundary [1] If(13)lt (ld)lt 15 (shaded region shown in Figure 3) theamplitude spectrum typically has two peaks a higher fre-quency peak corresponding to the depth of the flaw whichcan be obtained only if the impact contact time is sufficientlyshort and a lower frequency peak that would be lower thanthe thickness frequency of the unflawed plate

Figure 4 shows a typical precast shear wall panel as anexample to clarify the above rules In engineering practicethe grouting hole could be at different locations as shown inthe figure Given a grouting hole with the diameter of35mm the hole depth in Figures 4(a) and 4(b) can bemeasured because the values of ld are 07 and 0467 re-spectively which fall within the shaded region of Figure 3 Ifthe grouting hole is located at the midthickness of the wall(Figure 4(c)) the depth could also be measured since ld is035 in this case However in the case of Figures 4(d) and4(e) the ld values are 028 and 0233 which are lower than13 and the depth cannot be measured Furthermore theflaw in the case of Figure 4(e) cannot be detected because theld value is 0233 which is smaller than 025

3 Experimental Investigations

31 Test Specimen and Instruments An experimental in-vestigation was conducted to study whether the IE methodcould be used to detect the voids in grouted lap-spliceconnections in a precast shear wall e dimensions of thespecimen are shown in Table 1 Details of the specimen canbe found in Figure 5 ere are 18 typical grouting holes in

the specimen with 9 holes (ie hole A through I) at each testsurface (ie test surfaces 1 and 2) Here the conditions ofholes A B C G H and I at test surface 1 were the same astest surface 2 Hole A consisted of solid grout with steel barsHole B consisted of only solid grout Hole C had no groutbut had steel bars Holes G H and I consisted of defectivegrout and steel bars Plastic foam was used to form defects of10 20 and 30 of the hole volume Holes D E and F attest surface 1 had defects of 10 20 and 30 respectivelywhereas at test surface 2 they were all solid grout with steelbars A test on solid concrete of the shear wall was alsoconducted for reference erefore a total of 10 test con-ditions were considered in this study

e IE test system used in this study was SPC-MATSdeveloped by Sichuan Central Inspection Technology Inc asshown in Figure 6 A sampling frequency of 500 kHz andlength of 4096 points were used to capture the waveformsfor a record length of 8192ms e frequency resolution inthe computed amplitude spectra was 0122 kHz A steel ballwith a diameter of 6mmwas used for impact A piezoelectricaccelerometer produced by Fuji Ceramics Corporation witha working frequency up to 15 kHz was adopted and theelectronic signals amplified were transferred into the digitalsignals through data acquisition and processing moduleetest lines were arranged on both sides directly above theholes As shown in Figure 7 the measuring points werearranged at intervals of 40mm along the test line directione distance between the impact point and the receiverlocation was between 20 and 30mm ere are 20 testingpoints along each hole Points 1ndash15 are located directly overthe hole and Points 16ndash20 are located in the solid part toobtain the solid thickness frequency

32 Test Results Figures 8(a)ndash8(j) illustrate examples of thewaveforms and amplitude spectra of the 10 test conditionsEach figure represents one impact and it should be men-tioned that the results obtained from different impacts at onepoint remained almost the same In Figure 8(j) it can be seenthat the measured peak frequency of the solid wall(9644 kHz) agrees well with the calculated value (950 kHz)using equation (1) while the Vp is 3960ms e test resultsobtained from Hole A were the same as the solid concrete

l

Depth can bemeasured Depth cannot be

measuredld lt 13

l

ldquoInfiniterdquo flawld gt 15

Flawd

Figure 3 Smallest detectable horizontal crack or void [1](l length of flaw d depth of flaw)

Shock and Vibration 3

condition including the time-history response and thefrequency response indicating that the hole A behaved as asolid infill material For holes with grout defects the pre-dominant frequency did not change until a considerabledefect occurred (ie hole F H and I) e empty hole Cpresented the lowest predominant frequency due to the hole(Figure 8(c)) is was because the propagation path of thestress wave was the longest due to no grout in the hole whichproduced a longer travel time Also it should be mentionedthat Figure 8(c) shows only one peak in the amplitudespectrum although two holes existed which is because thefrequency corresponding to the depth of the nearest hole wasbeyond the measuring range of the instrument In additionfor some holes (eg Figure 8(e)) the obtained frequencymight not indicate a defect although it was theoreticallydetectable owing to the limited defect size compared withthe size of the whole specimen Taken together the pre-dominant frequency decreased with the increase of the voidin the grout indicating that the IE method offers the po-tential to detect defects in grouted lap-splice connections inprecast shear walls

In order to facilitate an in-depth understanding on theperformance of IE method the peak frequency obtained ateach measuring point along each hole are shown in Figure 9in which ldquominus 1rdquo and ldquominus 2rdquo represent results obtained at testsurfaces 1 and 2 respectively For hole A the peak frequencyvalues at the measuring points 1ndash15 were almost equal to the

values at measuring points 16ndash20 (ie around 9644 kHz)although slight scatter existed at some measuring points onsurface 1 and they were also equal to the frequency values ofhole B ese results indicate that the fully grouted holesbehaved as solid concrete and the bars did not affect theobtained frequency value However for empty hole C thepeak frequencies at measuring points 1ndash15 were obviouslylower than those at measuring points 16ndash20 Due to nogrouting inside hole C the propagation path of the stress waveincreased which decreased at the obtained peak frequency

For hole G (10 void) the peak frequencies at measuringpoints 1ndash15 were slightly inferior to 9644 kHz However thepeak frequencies for holes H (20 void) and I (30 void)were as low as 9277 kHz which indicates that with theincrease of the defect the peak frequency would be reducedSimilar observations can be seen for holes D E and F Hereit should be noted that the depth of the defect could not bediscerned because the shifted frequency values were almostequal for the two test surfaces However the test resultsindicated that the IE method offered a good potential toindicate the relative level of the defect in the grouted lap-splice connections

4 Finite Element Analysis

Two dimensional (2D) finite element (FE) analyses [19ndash21]based on the general purpose FE software ABAQUS were

Impact

50cm

35cm200

cm

(a)

35cm

75cm

Impact

(b)

100cm

35cm

Impact

(c)

35cm

125cm

Impact

(d)

150cm

35cm

Impact

(e)

Figure 4 Ratios of the lateral dimension and depths of a 35mm hole (a) ld 07 (b) ld 0467 (c) ld 035 (d) ld 028 (e) ld 0233

Table 1 Details of the specimen

Dimension (mm) Diameter of hole(mm)

Hole length(mm) Diameter of steel bar (mm) Anchorage length of steel bar (mm) hg

(mm)

2000times1000times 200 35 630 16 600 30Note hg is the constructional measure height (see Figure 1) which is equal to the diameter of the grouting outlet hole in this study


used to simulate the IE test After a working model wasdeveloped a parametric study was conducted to investigatethe effect of the hole depth on the peak frequency in theamplitude spectrum Details of the FE model the com-parison between test and analytical results and the para-metric study results are presented in this section

41 General Description e view of the whole model isshown in Figure 10 Plane strain elements were used formodeling the concrete and the grout In the model perfectbond was assumed between concrete and grout (ie the ldquoTIErdquocommand in ABAQUS was used) In order to simulate thedifferent defect levels the grout shape was defined accordingthe sectional view in Figure 5(d)e impact point is set abovethe defect and the recording point is set 3 cm away from the

Test surface 1 (front side)

Test surface 2 (back side)

(a)

A B C D E F G H I

Solidwithout bar

Solidwith bar

Baronly

10defect

20defect

30defect

10defect

30defect

20defect

Bar

1135mm

200mmlowast10 = 2000mm

600m

m30

mm 57

0mm

(b)

Solidwithout bar

Solidwith bar

Baronly

Solid withbar

Solidwith bar

Solidwith bar

10defect

30defect

20defect

A B C D E F G H I

Bar35mm


11

600m

m30

mm 57

0mm

(c)

2000 Test surface 1

200 20050

375

A B C D E F G H I

Test surface 2

ϕ35 Solid

DefectDefect

40 425

375 425

375 42540

40

200

(d)

Figure 5 Details of the shear wall test specimen (a) Photo of the test specimen (b) Details of test surface 1 (c) Details of test surface 2(d) Section 1-1

Impactor

Amplifier

Laptopcomputer

Receiver

Figure 6 Instruments for IE test


Testline

Prepared hole

4c

m

Impact point

30m

m

Anc

hora

ge le

ngth

of b

ar

600m

m

35mm

Bar

4cm

4c

m

7cm

Space for grouting outletReceiver location

2~3c

m

12

34

56

78

910

1112

1314

15

Figure 7 Test scheme

Am

plitu

deA

mpl

itude

Experimental spectrumImpact9644kHz

02 04 06 08 1000Time (ms)

ndash12ndash09ndash06ndash03

0003060912

02468

1012

15 20 25 3010Frequency (kHz)

(a)

Am

plitu

deA

mpl

itude

Impact

Experimental spectrum9644kHz

02 04 06 08 1000Time (ms)


0005101520

02468

1012


(b)

Figure 8 Continued


Am

plitu

deA

mpl

itude

ImpactExperimental spectrum

8911kHz

02 04 06 08 1000Time (ms)

ndash12ndash10ndash08ndash06ndash04ndash02

00020406081012

02468

1012


(c)A

mpl

itude

Am

plitu

de

Impact

Experimental spectrum

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012

(d)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(e)

Am

plitu

deA

mpl

itude

9277kHz Impact

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(f )

Figure 8 Continued


impact point e material properties of the concrete andgrout are shown in Table 2 In order to ensure the accuracy ofthe FE analysis the element size was set as 5mm [2] eexplicit dynamic analysis method was used e impactduration was 25 μs A load value of 5N was adopted in theanalysise time-history of the impact force is assumed to bea half sine curve e record length is 6ms with the samplingfrequency of 500 kHz e translation degrees of freedom atthe left and right edges of the models in Figure 10 were fixed

42 Comparison between Test and Analysis ResultsFigure 11 shows the propagation of stress waves in the modelunder impact loading After the analysis was completed thepeak frequency values from the test and analytical results werecompared as shown in Table 3 It can be seen from the tablethat the analytical results agreed well with the test results eexperimental wave speed in solid part of the wall which wascalculated to be 4020ms by equation (1) was slightly higherthan the value of 3960ms used in the model e maximum

Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)

Figure 8 Waveforms and amplitude spectra obtained under different conditions (a) Solid grout with reinforcement (hole A) (b) Solidgrout without reinforcement (hole B) (c) Ungrouted (hole C) (d) Grout defect 10 at test surface 1 (hole D) (e) Grout defect 20 at testsurface 1 (hole E) (f ) Grout defect 30 at test surface 1 (hole F) (g) Grout defect 10 at test surfaces 1 and 2 (hole G) (h) Grout defect 20at test surfaces 1 and 2 (hole H) (i) Grout defect 30 at test surfaces 1 and 2 (hole I) (j) Solid concrete (hole J)


Solid platethickness frequency

A-2A-1

0

4

8

12

16

20

24

Test

poin

t

925 1085Frequency (kHz)

(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)

Figure 9 Test results of all holes in the specimen (a) Hole A (solid) (b) Hole B (solid) (c) Hole C (empty) (d) Hole D (10-solid) (e) HoleE (20-solid) (f ) Hole F (30-solid) (g) Hole G (10) (h) Hole H (20) (i) Hole I (30)


error between the experimental and analytical frequencies was283 In the FE analysis the ratio of frequency between holeC (empty) and hole A (solid) was 0947 which is similar to theexperimental value of 0924 e higher value for the ex-perimental peak frequency for the solid wall means that theactual concrete had a slightly higher wave speed than used inthe FEmodelese observations indicated that the FE modelcould be used for modelling the frequency response ofgrouted lap-splice connections in the walls

43 Parametric Analysis Based on the validated model aparametric study was conducted to investigate the effect ofthe depth of an empty hole on the peak frequency responsein the amplitude spectrum A total of five depths were

considered 50 75 100 125 and 150mme hole diameterwas 35mm and the thickness of the wall was 200mm eelement size boundary conditions and material propertiesremained the same as the model mentioned above

e amplitude spectrums for the different hole depths areshown in Figure 12 e peak frequency (f1) the frequencybased on the reflection of hole (f2) the corresponding am-plitude and the back-calculated depth by equation (1) aresummarized in Table 4 Here the wave path regarding f1 andf2 can be seen in Figure 12(f) It could be seen from the tablethat the back-calculated depth based on f2 agreed well with thenumerical model However the corresponding amplitude off2 was lower (See Figures 12(a)ndash12(e)) and it was hard to beobtained in engineering practice In addition the modefrequencies of the specimen can be seen in the frequency

1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)

Figure 10 Details of the 2-D finite element model (a) Solid specimen (b) Hole in the specimen

Table 2 Material properties

Material Mass density (kgm3) Youngrsquos modulus (GPa) Poissonrsquos ratio Vp (ms)Concrete 2440 345 02 3960Grout 2500 330 02 3830

P-wave

S-wave

ReflectedP-wave

R-wave

Figure 11 Wave propagation simulation

Table 3 Comparison of experimental and analytical results

Conditions Defect ratio () FE analysis frequency value (kHz) Experimental frequency value (kHz) Error ()Hole A and B 0 9497 9644 152Hole D 10 9497 9644 152Hole E 20 9330 9277 057Hole F 30 9330 9277 057Hole G 10 9497 9644 152Hole H 20 9330 9277 057Hole I 30 9163 8911 283Hole C 100 8997 8911 097


spectrum For example in Figure 12(d) the peak value of25 kHz was the ninth mode frequency of the specimen

e relationships between f1 the corresponding am-plitudes and hole depth are summarized in Figure 13 Itcan be seen that as the hole depth increased the peakfrequency value initially decreased with depth until thehole was at the midthickness of the wall en the fre-quency increased with increasing depth e response was

symmetrical However the amplitude of the frequencypeak decreased with increasing depth of the hole isobservation might help to further clarify the location ofthe void since the signal of f1 was easy to obtain in en-gineering practice which is essential in precast shear wallflaw detecting However it should be mentioned that thecalibration was probably required to facilitate an accurateamplitude in test

50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8

8 16 24 32 400Frequency (kHz)


0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30

3012 18 2460Frequency (kHz)

(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver

Wave pathregarding f1


(f)

Figure 12 Corresponding frequencies of different depths of hole (a) 50mm (b) 75mm (c) 100mm (d) 125mm (e) 150mm (f) Wavepath


5 Conclusions

is study was mainly focused on investigating the feasibilityof the impact-echo (IE) method in detecting defects ingrouted lap-splice connections in precast walls To this endexperimental investigations were conducted rstly Eighteengrouting holes with dierent levels of articial defects wereprepared in a shear wall specimen and the IE method wasused to obtain the frequency response data In additionnite element (FE) analyses were conducted to simulate theIE test and a parametric study was conducted to investigatethe eect of the depth of an empty hole on the peak fre-quency value and its amplitude e results obtained in thisstudy allowed the following conclusions to be drawn

(1) e presence of a defect in the grout is indicated by ashift in the solid plate thickness frequency to a lowervalue Based on the test results the IE methoddemonstrated a good potential to detect groutingdefects and could even provide a qualitative indicationthe defect level in grouted lap-splice connections

(2) e proposed FE model was conrmed to be suitableto simulate the dynamic response of the wall withgrouting holes based on the comparison between testand analysis results

(3) Based on the parametric study as the hole depth in-creased the peak frequency decreased to a minimumvalue with the hole at the middle of the wall and then

increased in a symmetric manner e amplitudedecreased continuously with increasing depth

(4) e parametric study also indicated that frequencyshift to a lower value cannot be used as an indicatorof the depth of the defect in engineering practice

is study adopted a steel ball with a diameter of 6mmused as impactor and an acceleration sensor whereas thosefacilities are hard to catch high frequency response Infurther study dierent types of the facilities (eg tiny steelball with conical displacement transducer) suitable fordetecting the shallow defects discussed in this study will beadopted to validate the application of the IE method ingrouting defect detection In addition in order to estimatethe depth of the defect from the amplitude spectrum acalibration on the obtained signal amplitude might be re-quired in the future

Data Availability

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

Conflicts of Interest

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

Table 4 Results of parametric analysis

Buried depth (mm) 50 75 100 125 150f1 (kHz) 9166 883 866 883 9166Amplitude (10minus 8) 448 345 237 200 193Back-calculated depth based on f1 (mm) 20738 21527 21942 21527 20738f2 (kHz) 3850 2550 1983 1550 1266Amplitude (10minus 8) 008 019 045 078 038Back-calculated depth based on f2 (mm) 4937 7454 9585 12260 15014

Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)

Figure 13 Relationships between frequency amplitude and hole depth (a) Relationship between frequency and hole depth (b) Re-lationship between amplitude and hole depth


Acknowledgments

e authors appreciate the financial support from the NationalKey Research and Development Program of China(2016YFC0701802 2016YFC0701507 and 2011BAJ03B04) andAnhui Provincial Natural Science Foundation (1908085ME144)In addition the following companies are gratefully acknowl-edged for their material donations and assistance to the projectAnhui Hailong Construction Industry Co LTD and ShenzhenModern Construction Technology Co LTD

References

[1] N J Carino ldquoe impact-echo method an overviewrdquo inProceedings of the 2001 Structures Congress and ExpositionWashington DC USA National Advances in NondestructiveTesting 12th edition May 2001

[2] M Sansalone and W B Streett Impact-Echo NondestructiveTesting of Concrete and Masonry Bullbrier Press Ithaca NYUSA 1997

[3] F Schubert and B Kohler ldquoTen lectures on impact-echordquoJournal of Nondestructive Evaluation vol 27 no 1ndash3pp 5ndash21 2008

[4] F Schubert H Wiggenhauser and R Lausch ldquoOn the ac-curacy of thickness measurements in impact-echo testing offinite concrete specimensndashndashnumerical and experimental re-sultsrdquo Ultrasonics vol 42 no 1ndash9 pp 897ndash901 2004

[5] A Gibson and J S Popovics ldquoLamb wave basis for impact-echo method analysisrdquo Journal of Engineering Mechanicsvol 131 no 4 pp 438ndash443 2005

[6] O Baggens and N Ryden ldquoSystematic errors in impact-echothickness estimation due to near field effectsrdquo NDT amp EInternational vol 69 pp 16ndash27 2015

[7] Y Lin and M Sansalone ldquoDetecting flaws in concrete beamsand columns using the impact-echo methodrdquo ACI MaterialsJournal vol 89 no 4 1992

[8] C Hsiao C-C Cheng T Liou and Y Juang ldquoDetecting flawsin concrete blocks using the impact-echo methodrdquo NDT amp EInternational vol 41 no 2 pp 98ndash107 2008

[9] C-T Hsieh and Y Lin ldquoDetecting debonding flaws at theepoxy-concrete interfaces in near-surface mounted CFRPstrengthening beams using the impact-echo methodrdquo NDT ampE International vol 83 no 3 pp 1ndash13 2016

[10] W F Tawhed and S L Gassman ldquoDamage assessment ofconcrete bridge decks using Impact-Echo methodrdquo ACIMaterial Journal vol 99 no 3 2002

[11] Y Lin and K-L Lin ldquoTransient impact response of bridgei-girders with and without flawsrdquo Journal of Bridge Engi-neering vol 2 no 4 pp 131ndash138 1997

[12] D G Aggelis T Shiotani and K Kasai ldquoEvaluation ofgrouting in tunnel lining using impact-echordquo Tunnelling andUnderground Space Technology vol 23 no 6 pp 629ndash6372008

[13] J M Kang S Song D Park and C Choi ldquoDetection ofcavities around concrete sewage pipelines using impact-echomethodrdquo Tunnelling and Underground Space Technologyvol 65 pp 1ndash11 2017

[14] M T A Chaudhary ldquoEffectiveness of impact echo testing indetecting flaws in prestressed concrete slabsrdquo Constructionand Building Materials vol 47 pp 753ndash759 2013

[15] M Sansalone and N J Carino ldquoDetecting honeycombing thedepth of surface-opening cracks and ungrouted ducts using

the impact-echo methodrdquo Concrete International vol 10no 4 1988

[16] N J Carino and M Sansalone ldquoDetecting voids in groutedducts using the impact-echo methodrdquo ACI Materials Journalvol 89 no 3 1992

[17] B J Jaeger M J Sansalone and R W Poston ldquoDetectingvoids in grouted tendon ducts of post-tensioned concretestructures using the Impact Echo Methodrdquo ACI StructuralJournal vol 93 no 4 1996

[18] R Muldoon A Chalker M C Forde M Ohtsu andF Kunisue ldquoIdentifying voids in plastic ducts in post-ten-sioning prestressed concrete members by resonant frequencyof impact-echo SIBIE and tomographyrdquo Construction andBuilding Materials vol 21 no 3 pp 527ndash537 2007

[19] M Sansalone N J Carino and N N Hsu ldquoA finite elementstudy of transient wave propagation in platesrdquo Journal ofResearch of the National Bureau of Standards vol 92 no 4pp 267ndash278 1987

[20] M Sansalone N J Carino and N N Hsu ldquoA finite elementstudy of the interaction of transient stress waves with planarflawsrdquo Journal of Research of the National Bureau of Stan-dards vol 92 no 4 pp 279ndash290 1987

[21] M Hill J Mchugh and J D Turner ldquoCross-sectional modesin impact-echo testing of concrete structuresrdquo Journal ofStructural Engineering vol 126 no 2 pp 228ndash234 2000


International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018


Active and Passive Electronic Components

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of



Journal ofEngineeringVolume 2018

SensorsJournal of



RotatingMachinery


Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation


Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

flaws in various structural components such as prestressedconcrete slabs [6] reinforced concrete beams and columns[7] concrete blocks [8] epoxy-concrete interface [9] bridgedecks [10] I-girders [11] tunnel linings [12] cavities aroundconcrete sewage pipelines [13] prestressed concrete slabs[14] and grouting of prestressed concrete structuralmembers [15ndash18]

Although research has been conducted in this fieldthere is a lack of information on the application of the IEmethod in defect detection of grouted lap-splice con-nections erefore the objective of this study is to in-vestigate whether the existing IE method could be used todetect grouting defects in grouted lap-splice connectionsof shear walls For this purpose a precast shear wallcontaining grouting holes with a series of artificial defectswas used to investigate the applicability of the IE methode frequency response of the grouted holes with differentdefect levels were determined and compared in detail Inaddition finite element (FE) analyses were conducted tosimulate the test and a parametric study was conducted toinvestigate the effect of hole depth on the frequencyresponse

2 Theory and Test System of the Impact-Echo(IE) Method

21 ampeory of the IE Method e IE method is a NDTtechnique that incorporates the principle of low-frequencytransient stress wave propagation e principle of the IEtechnique is illustrated in Figure 2 in which T is thedistance from the internal defect to the top plate surfaceand ∆t is the time when the P-wave first arrives at the signalreceiving point A small steel ball is used to impact thespecimen surface which generates stress waves thatpropagate through the test specimen ree types of wavesare generated which are named as P- S- and R-waves eP-wave and S-wave are associated with particle motionparallel and perpendicular to the propagation directionrespectively e R-wave (also known as Rayleigh wave) is asurface wave that travels along the solid surface In the IEmethod the measured displacement response is mainly

influenced by the P-wave owing to the close location of thesensor and impact point [1 2] Reflection refraction anddiffraction would occur when these waves encounter in-terfaces between materials with different acousticimpedances

e sensor responds to the arrival of reflected waves andthe recorded time domain signals are transformed into thefrequency domain using the fast Fourier transform (FFT)technique e frequency with peak amplitude in the ob-tained spectrum represents the dominant frequency in thewaveform is dominant frequency also known as thethickness frequency can be estimated as

f βK

n

Vp

T (1)

where K is a geometric correction factor that is determinedby the geometrical shape of the structure [3] n is a constantfactor either equal to 2 or 4 depending on the acousticimpedances [3] β is an empirical correction factor which hasa value of 096 [1 2] or 095 [4 5] andVp is the P-wave speedand is calculated through Vp E(1 minus ])[ρ(1 + ])1113864

(1 minus 2])]05 where E ρ and ] are the elastic modulusdensity and Poissonrsquos ratio of the test object respectively

Precast wall

Lapped rebar in grouting holeFloor

Protruding rebar

Rebar inside precast wall

Spiral stirrup

Protruding rebar

Groutinginlet

Groutingoutlet

Grout

Figure 1 Reinforced mortar anchor lap connection

p-wave

R-wave

Time

Time

ReceiverImpact

Force

Contacttime

Disp

lacement

Δt

T

Figure 2 Principle of the impact-echo method [1]



22 IE Test









l


measuredld lt 13

l


Flawd









Impact

50cm

35cm200

cm

(a)

35cm

75cm

Impact

(b)

100cm

35cm

Impact

(c)

35cm

125cm

Impact

(d)

150cm

35cm

Impact

(e)





(mm)







(a)

A B C D E F G H I

Solidwithout bar

Solidwith bar

Baronly

10defect

20defect

30defect

10defect

30defect

20defect

Bar

1135mm


600m

m30

mm 57

0mm

(b)

Solidwithout bar

Solidwith bar

Baronly

Solid withbar

Solidwith bar

Solidwith bar

10defect

30defect

20defect

A B C D E F G H I

Bar35mm


11

600m

m30

mm 57

0mm

(c)

2000 Test surface 1

200 20050

375

A B C D E F G H I

Test surface 2

ϕ35 Solid

DefectDefect

40 425

375 425

375 42540

40

200

(d)


Impactor

Amplifier

Laptopcomputer

Receiver



Testline

Prepared hole

4c

m

Impact point

30m

m

Anc

hora

ge le

ngth

of b

ar

600m

m

35mm

Bar

4cm

4c

m

7cm


2~3c

m

12

34

56

78

910

1112

1314

15


Am

plitu

deA

mpl

itude


02 04 06 08 1000Time (ms)


0003060912

02468

1012


(a)

Am

plitu

deA

mpl

itude

Impact


02 04 06 08 1000Time (ms)


0005101520

02468

1012


(b)

Figure 8 Continued


Am

plitu

deA

mpl

itude


8911kHz

02 04 06 08 1000Time (ms)


00020406081012

02468

1012


(c)A

mpl

itude

Am

plitu

de

Impact


9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012

(d)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(e)

Am

plitu

deA

mpl

itude

9277kHz Impact

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(f )

Figure 8 Continued




Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)




A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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



22 IE Test









l


measuredld lt 13

l


Flawd









Impact

50cm

35cm200

cm

(a)

35cm

75cm

Impact

(b)

100cm

35cm

Impact

(c)

35cm

125cm

Impact

(d)

150cm

35cm

Impact

(e)





(mm)







(a)

A B C D E F G H I

Solidwithout bar

Solidwith bar

Baronly

10defect

20defect

30defect

10defect

30defect

20defect

Bar

1135mm


600m

m30

mm 57

0mm

(b)

Solidwithout bar

Solidwith bar

Baronly

Solid withbar

Solidwith bar

Solidwith bar

10defect

30defect

20defect

A B C D E F G H I

Bar35mm


11

600m

m30

mm 57

0mm

(c)

2000 Test surface 1

200 20050

375

A B C D E F G H I

Test surface 2

ϕ35 Solid

DefectDefect

40 425

375 425

375 42540

40

200

(d)


Impactor

Amplifier

Laptopcomputer

Receiver



Testline

Prepared hole

4c

m

Impact point

30m

m

Anc

hora

ge le

ngth

of b

ar

600m

m

35mm

Bar

4cm

4c

m

7cm


2~3c

m

12

34

56

78

910

1112

1314

15


Am

plitu

deA

mpl

itude


02 04 06 08 1000Time (ms)


0003060912

02468

1012


(a)

Am

plitu

deA

mpl

itude

Impact


02 04 06 08 1000Time (ms)


0005101520

02468

1012


(b)

Figure 8 Continued


Am

plitu

deA

mpl

itude


8911kHz

02 04 06 08 1000Time (ms)


00020406081012

02468

1012


(c)A

mpl

itude

Am

plitu

de

Impact


9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012

(d)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(e)

Am

plitu

deA

mpl

itude

9277kHz Impact

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(f )

Figure 8 Continued




Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)




A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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








Impact

50cm

35cm200

cm

(a)

35cm

75cm

Impact

(b)

100cm

35cm

Impact

(c)

35cm

125cm

Impact

(d)

150cm

35cm

Impact

(e)





(mm)







(a)

A B C D E F G H I

Solidwithout bar

Solidwith bar

Baronly

10defect

20defect

30defect

10defect

30defect

20defect

Bar

1135mm


600m

m30

mm 57

0mm

(b)

Solidwithout bar

Solidwith bar

Baronly

Solid withbar

Solidwith bar

Solidwith bar

10defect

30defect

20defect

A B C D E F G H I

Bar35mm


11

600m

m30

mm 57

0mm

(c)

2000 Test surface 1

200 20050

375

A B C D E F G H I

Test surface 2

ϕ35 Solid

DefectDefect

40 425

375 425

375 42540

40

200

(d)


Impactor

Amplifier

Laptopcomputer

Receiver



Testline

Prepared hole

4c

m

Impact point

30m

m

Anc

hora

ge le

ngth

of b

ar

600m

m

35mm

Bar

4cm

4c

m

7cm


2~3c

m

12

34

56

78

910

1112

1314

15


Am

plitu

deA

mpl

itude


02 04 06 08 1000Time (ms)


0003060912

02468

1012


(a)

Am

plitu

deA

mpl

itude

Impact


02 04 06 08 1000Time (ms)


0005101520

02468

1012


(b)

Figure 8 Continued


Am

plitu

deA

mpl

itude


8911kHz

02 04 06 08 1000Time (ms)


00020406081012

02468

1012


(c)A

mpl

itude

Am

plitu

de

Impact


9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012

(d)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(e)

Am

plitu

deA

mpl

itude

9277kHz Impact

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(f )

Figure 8 Continued




Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)




A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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






(a)

A B C D E F G H I

Solidwithout bar

Solidwith bar

Baronly

10defect

20defect

30defect

10defect

30defect

20defect

Bar

1135mm


600m

m30

mm 57

0mm

(b)

Solidwithout bar

Solidwith bar

Baronly

Solid withbar

Solidwith bar

Solidwith bar

10defect

30defect

20defect

A B C D E F G H I

Bar35mm


11

600m

m30

mm 57

0mm

(c)

2000 Test surface 1

200 20050

375

A B C D E F G H I

Test surface 2

ϕ35 Solid

DefectDefect

40 425

375 425

375 42540

40

200

(d)


Impactor

Amplifier

Laptopcomputer

Receiver



Testline

Prepared hole

4c

m

Impact point

30m

m

Anc

hora

ge le

ngth

of b

ar

600m

m

35mm

Bar

4cm

4c

m

7cm


2~3c

m

12

34

56

78

910

1112

1314

15


Am

plitu

deA

mpl

itude


02 04 06 08 1000Time (ms)


0003060912

02468

1012


(a)

Am

plitu

deA

mpl

itude

Impact


02 04 06 08 1000Time (ms)


0005101520

02468

1012


(b)

Figure 8 Continued


Am

plitu

deA

mpl

itude


8911kHz

02 04 06 08 1000Time (ms)


00020406081012

02468

1012


(c)A

mpl

itude

Am

plitu

de

Impact


9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012

(d)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(e)

Am

plitu

deA

mpl

itude

9277kHz Impact

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(f )

Figure 8 Continued




Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)




A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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


Testline

Prepared hole

4c

m

Impact point

30m

m

Anc

hora

ge le

ngth

of b

ar

600m

m

35mm

Bar

4cm

4c

m

7cm


2~3c

m

12

34

56

78

910

1112

1314

15


Am

plitu

deA

mpl

itude


02 04 06 08 1000Time (ms)


0003060912

02468

1012


(a)

Am

plitu

deA

mpl

itude

Impact


02 04 06 08 1000Time (ms)


0005101520

02468

1012


(b)

Figure 8 Continued


Am

plitu

deA

mpl

itude


8911kHz

02 04 06 08 1000Time (ms)


00020406081012

02468

1012


(c)A

mpl

itude

Am

plitu

de

Impact


9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012

(d)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(e)

Am

plitu

deA

mpl

itude

9277kHz Impact

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(f )

Figure 8 Continued




Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)




A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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


Am

plitu

deA

mpl

itude


8911kHz

02 04 06 08 1000Time (ms)


00020406081012

02468

1012


(c)A

mpl

itude

Am

plitu

de

Impact


9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012

(d)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(e)

Am

plitu

deA

mpl

itude

9277kHz Impact

02 04 06 08 1000Time (ms)



00020406081012

02468

1012


(f )

Figure 8 Continued




Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)




A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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




Am

plitu

deA

mpl

itude

Impact

9644kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(g)A

mpl

itude

Am

plitu

de Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(h)

Am

plitu

deA

mpl

itude

Impact9277kHz


00020406081012

02468

1012



02 04 06 08 1000Time (ms)

(i)

Am

plitu

deA

mpl

itude

Impact

9644kHz

02 04 06 08 1000Time (ms)


02468

1012


00020406081012


(j)




A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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



A-2A-1

0

4

8

12

16

20

24

Test

poin

t


(a)

B-2B-1

0

4

8

12

16

20

24

Test

poin

t


(b)

C-2C-1


0

4

8

12

16

20

24

Test

poin

t

(c)

D-2D-1

0

4

8

12

16

20

24Te

st po

int


(d)

Figure 9 Continued



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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



E-2E-1

0

4

8

12

16

20

24

Test

poin

t

(e)

F-2F-1

0

4

8

12

16

20

24

Test

poin

t


(f )

G-2G-1

0

4

8

12

16

20

24

Test

poin

t


(g)

H-2H-1

0

4

8

12

16

20

24Te

st po

int


(h)

I-2I-1

0

4

8

12

16

20

24

Test

poin

t


(i)







1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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






1000mm

Impact Receiver20

0mm

(a)

Impact Receiver

1000mm

35mm

200m

m 50m

m50

mm

(b)




P-wave

S-wave

ReflectedP-wave

R-wave








50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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





50m

m

Am

plitu

de 9166kHz385kHz

Am

plitu

de

0

2

4

6

8



0001020304

(a)

Am

plitu

de

75m

m

255kHz

883kHz

0

1

2

3

4

5

6


(b)

Am

plitu

de

1983kHz

867kHz 100m

m

0

1

2

3

4


(c)

Am

plitu

de

125m

m

25kHz

155kHz

883kHz

00

06

12

18

24

30


(d)

Am

plitu

de

9166kHz

1266kHz

150m

m

00

06

12

18

24

30


(e)

Impact Receiver



(f)



5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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


5 Conclusions








Data Availability






Freq

uenc

y (k

Hz)

86

87

88

89

90

91

92

93

60 80 100 120 140 16040Hole depth (mm)

(a)

Am

plitu

de (1

0ndash8)

60 80 100 120 140 16040Hole depth (mm)

15

20

25

30

35

40

45

50

(b)



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


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


Documents

GroutingDefectDetectionofLappedBarConnections …downloads.hindawi.com/journals/sv/2019/1934240.pdf · 2019-10-14 · condition, including the time-history response and the frequencyresponse,indicatingthattheholeAbehavedasa