The Strength and Ductility of Lapped Splices of Reinforcing Bars in Tension

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Australian Journal of Structural Engineering

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The Strength and Ductility of Lapped Splices of Reinforcing Bars in Tension

R I Gilbert amp A E Kilpatrick

To cite this article R I Gilbert amp A E Kilpatrick (2015) The Strength and Ductility of Lapped

Splices of Reinforcing Bars in Tension Australian Journal of Structural Engineering 161 35-46

To link to this article httpdxdoiorg10715813287982201511465177

Published online 16 Nov 2015

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35

Paper S13-033 submitted 110913 accepted for publicationafter review and revision 260214

dagger Corresponding author EProf Ian Gilbert can be contacted atigilbertunsweduau

technical paper

The strength and ductility of lapped

splices of reinforcing bars in tension

RI Gilbertdagger

School of Civil and Environmental Engineering The University of New South Wales Sydney NSW

AE KilpatrickLa Trobe University Bendigo Victoria

ABSTRACT When designing a reinforced concrete member for strength ductility and robustnessit is essential that the tensile reinforcement at the critical section can not only develop the yieldstrength of the steel f

sy but that it can sustain this level of stress as deformation increases At a lapped

splice each bar must be fully anchored beyond the lap length The minimum lap lengths of deformedreinforcing bars in tension speci1047297ed in the Australian Standard for Concrete Structures AS3600-2009 were recently revised and a procedure similar to but less conservative than the provisionsin Eurocode 2 was adopted The new provisions require longer lap lengths for small diameter barsin slabs but considerably shorter lap lengths for larger diameter bars in beams and columns This paper reports on several series of tests that examine the ef1047297cacy of the AS 3600-2009 provisions fromthe perspectives of adequate strength and ductility Over 50 specimens containing both contact andnon-contact lapped splices have been tested The aim was to assess the current Australian provisionsand to examine the reliability and consistency of the factors of safety associated with lapped splicesIt is concluded that the strength requirements of AS3600-2009 are adequate for small diameter barsin slabs but may not provide an adequate factor of safety for large diameter bars in beams Also the

AS3600 provisions may not ensure suf1047297cient ductility of a lapped splice in members that use highstrength concrete Further tests are required to investigate these aspects

KEYWORDS Anchorage bond deformed bars development length ductility factor ofsafety lapped splice reinforced concrete ultimate strength

REFERENCE Gilbert R I amp Kilpatrick A E 2015 ldquoThe strength and ductility of lappedsplices of reinforcing bars in tensionrdquo Australian Journal of Structural Engineering Vol 16No 1 January pp 35-46 httpdxdoiorg107158S13-0332015161

1 INTRODUCTION

Reinforcing bars are normally supplied in lengthsof 6 m or so In members longer than this full stresstransfer from one bar to another is achieved by eitherwelding the bars together or by using mechanicalsplices or by lapping the bars over a nominateddistance (a structural lapped splice) In the lattercase each bar in the splice must be fully anchored beyond the lap length

This paper reports on an experimental programdesigned to examine the strength and deformation behaviour of lapped splices of reinforcing barsin tension and to assess the efficacy of the newprovisions for lapped splices in the AustralianStandard for Concrete Structures AS 3600-2009(Standards Australia 2009) from the perspectivesof adequate strength and ductility The differences in behaviour of contact and non-contact lapped splicesare examined and the impact of cyclic loading on the

anchorage requirements of reinforcing bars is alsoconsidered The long-term aim of this research isto develop procedures for anchoring reinforcementin concrete structures that provide reliable and

copy Institution of Engineers Australia 2015 Australian Journal of Structural Engineering Vol 16 No 1



36

Australian Journal of Structural Engineering Vol 16 No 1

ldquoThe strength and ductility of lapped splices of reinforcing bars in tensionrdquo ndash Gilbert amp Kilpatrick

consistent factors of safety and that allow structuresto be ductile and robust throughout their design lifewithout an increase in risk of premature collapsethrough bond and anchorage failure

When designing a reinforced concrete member forstrength ductility and robustness it is essential thatthe tensile reinforcement at the critical section can not

only develop the yield strength of the steel f sy butthat it can sustain that level of stress as deformationincreases ie suf1047297cient ductility If the yield strengthis to be reached and maintained a minimum length ofreinforcing bar (the development length) is requiredon either side of the critical section (or point ofpeak stress) Codes of practice specify a minimumdevelopment length over which a straight bar must be embedded in the concrete in order to developits full yield strength At a structural lapped splicewhere stress transfer is required the two parallel bars are developing stress in close proximity with

the bond stresses on each bar developing in oppositedirections The anchorage of each bar is adverselyaffected by the presence of the other bar and as aconsequence the minimum speci1047297ed length of thelapped splice is usually signi1047297cantly larger than thedevelopment length of a single bar

Existing approaches for calculating the lapped splicelength of reinforcement are empirical and based onstatistical analyses of test data The test data is usuallyobtained from static or slow load tests on laboratorytest specimens In the derivation of expressions forthe lapped splice length an average ultimate bondstress f

ub is usually assumed at the interface between

the concrete and the reinforcing bar even thoughextreme variations in local bond stresses exist alongthe development length particularly in the vicinityof 1047298exural cracks

The average ultimate bond stress is affected bynumerous factors including the

bull type of reinforcing bar (ribbed or deformed)

bull condition of the steel surface

bull degree of compaction of the concrete surroundingthe bar

bull concrete strength

bull amount and spacing of lateral reinforcement

bull magnitude and type of pressure normal to the bar

bull concrete cover and distance to the next parallel bar

bull amount of fresh concrete below the bars

bull nature of the applied loading (static or dynamic)

bull length of the anchorage

Although some research on the last two factors has been reported (Kim et al 2006 Wang 2009) these

effects have yet to be quanti1047297ed As the anchoragelength increases so too does the number of crackscrossing the development length and value of f

ub decreases

3 500 = 1500

100

Elevation

420

100

a

c

c1a

a

100

420

100

3 500 = 1500

Plan Section Contact splice

a

c

c1

Plan Section

Non-contact splice

Figure 1 Details of slabs tested in Series 1

A structural splice should not only have adequatestrength but also adequate ductility so as to avoida brittle failure under increasing deformation Itwould be unacceptable for a splice to just reach its fullstrength only to fail under a little further deformationIdeally the segment of a member in which the barsare spliced should have the same rotational capacity

as if the bars in the segment were continuous

2 LAPPED SPLICE LENGTH AS3600-2009

In order to realise the full yield strength of a barAustralian Standard AS3600-2009 (StandardsAustralia 2009) de1047297nes the basic development lengthof a deformed bar in tension as

1 3

1

2

292

sy b

sy tb b

c

k k f dL k d

k f

(1)

where k 1 = 13 for a horizontal bar with more than300 mm of concrete cast below the bar otherwise k

1 =

10 k 2 = (132 ndash d

b)100 k

3 = 10 ndash 015(c

d ndash d

b)d

b (but

07 le k 3 le 10) c

d is the smaller of the clear cover to the

nearest concrete surface (c orc1 in 1047297gure 1) or half the

clear spacing to the next parallel bar (a2 in 1047297gure1) f

sy = yield strength of the bar [MPa] d

b = diameter

of the bar [mm] and f crsquo= characteristic compressive

strength of concrete [MPa]

According to AS3600-2009 the development lengthof a deformed bar in tension (L

syt) shall be taken as

either the basic development length (Lsytb

) or where

the bene1047297cial effects of con1047297nement by transversereinforcement or transverse compressive pressureare available a re1047297ned (lesser) development lengthgiven by

Lsyt

= k 4k

5L

sytb (2)

where k 4 = 10 ndash K (but 07 le k

4 le 10) k

5 = 10 ndash 004

p

(but 07 le k 5 le 10) = ( A

tr ndash A

trmin) A

s A

tr

= cross-sectional area [mm2] of the transversereinforcement along the development length A

trmin

= cross-sectional area [mm2] of the minimum



37



transverse reinforcement which may be taken as025 A

s for beams and 0 for slabs A

s = cross-sectional

area [mm2] of a single bar of diameter db being

anchored K is a factor that accounts for the positionof the bars being anchored with respect to thetransverse reinforcement with K = 01 for bars inthe corner of a stirrup K = 005 for other bars within

a stirrup and K = 0 where no transverse steel exists between the bar and the nearest concrete surfaceand

p = transverse compressive pressure [MPa] at

the ultimate limit state along the development lengthperpendicular to the plane of splitting

If a stress st less than the yield strength of a bar is

to be developed then the required developmentlength may be reduced proportionally that is bythe ratio

st f

sy

In AS 3600-2009 the length of a lapped splice intension is in general required to be at least 25greater than the development length of the bar ie

Lsytlap = 125Lsyt but for non-contact spices in isolatedmembers (such as those tested here) the lap lengthmust not be less than 125L

syt or L

syt + 15s

b whichever

is the larger The symbol sb is the clear distance [mm]

between the bars being spliced (1047297gure 2)

Llap

100

600 600

600

150

P P

850

Llap

sb

All dimensions in mm

Figure 2 Details of a typical slab tested

in Series 2 ndash (a) elevation of thespecimen (b) plan of the specimen(c) cross-section at mid-span(d) test setup

(a)

(b)

(c)

(d)

3 EXPERIMENTAL PROGRAM

31 Series 1 tests

In this series a total of 32 slab specimens wereconstructed and tested (Haw amp Leskovec 2010Mitchell amp Sheppard 2010 Bilston amp Burke

2011 Duke amp Trask 2011) All specimens weresimply-supported one-way slabs subjected to thirdpoint loading as shown in figure 1 The tensilereinforcement in 30 of the slabs had lapped splicesof length L

lap (1047297gure 2) in the middle third region

where the bending moment was essentially constantThe remaining two specimens had bars that werecontinuous throughout Details of the specimens withthe lapped splices are shown in 1047297gure 1

The spliced bars were either in direct contact andlightly tied together with tie wire or were separatedas far as possible to form a non-contact splice as

shown in 1047297gure 1 The tensile reinforcement in eachspecimen consisted of either two N10 bars or twoN12 bars (Australian 10 or 12 mm diameter normalductility class deformed bar respectively) All barsin all specimens were cogged at their ends to ensurefull anchorage The cross-sectional dimensions of allspecimens tested in this series were 100 mm deep by420 mm wide and the side cover to the bars was c

1 =

50 mm Details and dimensions of each test specimenare given in table 1

All slabs were tested in a calibrated Avery universaltesting machine The specimens were subjected to

controlled deformation that was applied at a rateof about 2 mmminute measured at the centre ofthe slab This continued until catastrophic cracksdeveloped around the ends of and along the bars atthe splice and with increasing applied deformationthe slab began to unload The tests were terminatedprior to the slab breaking into pieces or for the slabswhere the steel yielded before the splice failed whenthe limit of the dial gauge was reached

32 Series 2 tests

In this series a total of 18 slab specimens with lappedsplices were tested (Yeow 2008 Gilbert et al 20112012) All specimens were simply-supported andsubjected to third point loading as shown in 1047297gure2 The tensile reinforcement in all of the slabs hadlapped splices in the middle third region wherethe moment was essentially constant Details of thespecimens with the lapped splices are shown in1047297gure 2

The spliced bars were either in direct contact andlightly tied together with tie wire or were separated by 28 mm (s

b) to form a non-contact splice as

shown in 1047297gure 2 The tensile reinforcement in eachspecimen consisted of either three or four N12 orN16 bars The cross-sectional dimensions of all slabspecimens tested were 150 mm deep by 850 mm



38



Table 1 Details of slab specimens in Series 1 (C = contact splice NC = non-contact splice)

Slab Splice type d [mm] Ast [mm2] f

cm [MPa] d

b [mm] Lap [mm] a [mm] s

b [mm] c [mm]

MC1 C 86 226 549 12 184 284 0 12

MNC1 NC 86 226 567 12 186 194 91 12

MC2 C 86 226 571 12 132 284 0 12

MNC2 NC 86 226 553 12 133 194 91 12

MC3 C 61 226 538 12 127 284 0 36

MNC3 NC 62 226 530 12 128 194 91 36

MC4 C 62 226 566 12 89 284 0 36

MNC4 NC 61 226 541 12 87 194 91 36

HC1 C 85 226 591 12 165 284 0 12

HNC1 NC 85 226 625 12 165 194 91 12

HC2 C 85 226 639 12 118 284 0 12

HNC2 NC 83 226 632 12 115 194 91 12

HC3 C 64 226 546 12 116 284 ndash 36

HNC3 NC 61 226 546 12 117 194 91 36

HN4 C 61 226 602 12 81 284 ndash 36

HNC4 NC 62 226 555 12 80 194 91 36

M30 C 75 157 320 10 82 290 0 20

M45 C 75 157 320 10 122 290 0 20

M60 C 75 157 328 10 160 290 0 20

M100A C 75 157 362 10 261 290 0 21

M100B C 75 157 369 10 263 290 0 22M150A C 75 157 343 10 397 290 0 22

M150B C 75 157 340 10 395 290 0 22

MC ndash 75 157 339 10 Continuous bars

H30 C 74 226 823 12 67 284 0 20

H45 C 74 226 741 12 104 284 0 20

H60 C 74 226 782 12 138 284 0 20

H100A C 74 226 703 12 222 284 0 20

H100B C 74 226 703 12 226 284 0 20

H150A C 74 226 711 12 328 284 0 20H150B C 74 226 727 12 337 284 0 20

HC ndash 74 226 814 12 Continuous bars

wide Details and dimensions of each slab specimenare given in table 2

All specimens were loaded slowly to failure in adeformation-controlled testing frame with failureinitiated in all specimens by splitting cracks and bond failure at the lapped splice To examine the

effects of cyclic loading on bond strength two of thespecimens (SL-4 and SL-7) were subjected to 50000cycles of service loads before being loaded to failureAnother two specimens were subjected to sustained

service loads and drying shrinkage for a period of 10months prior to loading to failure

32 Series 3 tests

Six beam specimens with lapped splices wereconstructed and tested All beams were simply-

supported over a span of 2100 mm with rectangularcross-sections 250 mm wide and 300 mm deep asshown in 1047297gure 3 As for the slab specimens theywere tested in four-point bending with the two



39



Table 2 Details of slab specimens tested in Series 2 (C = contact splice sb = 0 NC = non-contact splice

sb = 28 mm)


cm [MPa] d


b [mm] c [mm]

SS-1 C 119 452 12 318 150 125 180 25

SS-2 C 119 452 12 343 220 125 180 25

SS-3 C 119 339 12 343 150 125 276 25SS-4 C 119 339 12 348 220 125 276 25

SS-5 C 117 804 16 348 200 125 173 25

SS-6 C 117 804 16 352 280 125 173 25

SS-7 C 117 603 16 352 200 125 268 25

SS-8 C 117 603 16 356 280 125 268 25

SS-9 C 104 452 12 356 150 125 180 40

SS-10 C 104 339 12 369 220 125 276 40

SL-1 C 119 452 12 380 120 120 188 25

SL-2 C 119 452 12 380 180 120 188 25SL-3 C 119 452 12 380 240 120 188 25

SL-4 C 119 452 12 380 180 120 188 25

SL-5^ C 119 452 12 380 180 120 188 25

SL-6 NC 119 452 12 380 180 120 188 25

SL-7 NC 119 452 12 380 180 120 188 25

SL-8^ NC 119 452 12 380 180 120 188 25 SL-4 and SL-7 were subjected to 50000 cycles of service load before testing to failure ^ SL-5 and SL-8 were subjected to sustainedservice loads and shrinkage for 10 months before testing to failure


P P

Atr

150

300

Llap

100 700

700 700

2

N12

bars

300

250

2 N20 bars

(spliced)

Figure 3 Details of a typical beam tested in Series 3 ndash (a) elevation of the specimen and(b) cross-section at mid-span

applied loads each at 700 mm from the adjacentsupport Each specimen contained two N20 tensile bars (d

b = 20 mm) at an effective depth of 265 mm

with each bar lap spliced in the mid-span (constantmoment) region similar to the slab specimens Alllapped bars were contact splices The variablesconsidered were the lap length and the amount oftransverse reinforcement located within the lappedsplice ( A

trs) where A

tr is the area of the two vertical

legs of the closed stirrup and s is the stirrup spacingThe specimens with transverse steel contained10 mm diameter stirrups at either 150 mm or 100 mm

centres Three of the beam specimens (BL-3 BL-5 andBL-6) were subjected to 50000 cycles of service loads before being tested to failure Details and dimensionsof each beam specimen are given in table 3

4 TEST RESULTS

41 Preliminary remarks

The test results and associated analyses are givenin tables 4 5 and 6 The measured moment at thesplice location at failure ( M

max) is provided in the

fourth column of each table for those specimens thatsuffered bond failure at the splice The steel stressat failure (

st) shown in the seventh column of each

table is calculated from the maximum momentusing a cracked section analysis and assuming a

linear stress-strain relationship for the concrete incompression The lap length required to develop thespeci1047297ed yield strength of each bar L

sytlap speci1047297ed in

AS3600-2009 as 125Lsyt

is determined in accordance

(a) (b)



40



Table 3 Details of the beam specimens tested in Series 3

Beam d [mm] Ast [mm2] d

b [mm] A

tr s [mm] f

cm [MPa] Lap [mm] c

1 [mm] a [mm] c [mm]

BL-1 265 628 20 000 430 300 35 120 25

BL-2 265 628 20 000 430 400 35 120 25

BL-3 265 628 20 000 430 300 35 120 25

BL-4 265 628 20 157 430 300 35 120 25

BL-5 265 628 20 157 430 300 35 120 25

BL-6 265 628 20 105 430 300 35 120 25

BL-3 BL-5 and BL-6 were subjected to 50000 cycles of service load before testing to failure

Table 4 Results of Series 1 (slab) tests

Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

MC1 226 184 755 33900 693 422 356 065 193

MNC1 226 186 685 34200 688 383 347 060 187MC2 226 132 605 34300 686 338 279 047 212

MNC2 226 133 540 33900 693 302 276 043 208

MC3 226 127 508 33700 328 406 242 063 191

MNC3 226 128 451 33500 342 354 257 052 201

MC4 226 89 397 34200 336 312 181 046 204

MNC4 226 87 375 33700 328 300 216 037 248

HC1 226 165 693 34600 664 392 318 060 193

HNC1 226 165 631 35200 655 356 312 056 189

HC2 226 118 577 35500 650 326 255 045 216

HNC2 226 115 441 35300 620 255 223 040 194

HC3 226 116 498 33800 364 378 224 058 193

HNC3 226 117 441 33800 328 352 253 048 216

HN4 226 81 433 34800 320 345 195 043 240

HNC4 226 80 408 34000 338 320 229 034 286

M30 157 82 303 27700 450 279 215 029 262

M45 157 122 435 27700 450 401 309 044 253

M60 157 160 500 28000 446 460 350 058 219

M100A 157 261 ndash ndash ndash ndash ndash 101 ndash

M100B 157 263 ndash ndash ndash ndash ndash 105 ndashM150A 157 397 ndash ndash ndash ndash ndash 152 ndash

M150B 157 395 ndash ndash ndash ndash ndash 151 ndash

H30 226 67 410 38400 451 267 165 033 247

H45 226 104 603 37200 463 392 256 048 247

H60 226 138 640 37800 457 416 265 066 192

H100A 226 222 ndash ndash ndash ndash ndash 100 ndash

H100B 226 226 ndash ndash ndash ndash ndash 102 ndash



Mean 222

Standard deviation 030

Coef1047297cient of variation [] 135



41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216


Coef1047297cient of variation [] 154a subjected to 50000 cycles of service load before testing to failure b subjected to sustained service loads and shrinkage beforetesting to failure

Table 6 Results of Series 3 (beam) tests

Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128



with the procedure outlined in section 2 The length

required to develop the measured peak stress at the

lap (according to AS3600-2009) is Lstlap = 125Lsyt st f sy and this is shown in the third last column of each

table The factor of safety (FoS) is the ratio of Lstlap

divided by the actual lap length and is shown in the

1047297nal column The ratio of the actual lap length Llap

tothe AS3600-2009 value required to just develop the

yield strength Lsytlap is also presentedSince the bond strength of concrete is related toits tensile strength the capacity reduction factorassociated with the strength of the lap is taken as that



42



for concrete in tension namely = 06 A minimumtarget FoS of 1 = 106 = 167 is consideredappropriate and consistent with the requirementsof AS3600-2009

42 Series 1 tests

For the analysis of these tests the concrete modulusE

c was calculated using the formulae speci1047297ed in

AS3600-2009 and a typical density of concrete of2350 kgm3 The measured yield strengths of the bars used in the tests were 605 MPa for the N10 barsand 560 MPa for the N12 bars The results are shownin table 4

Comparisons between the load-de1047298ection curves ofthe slabs that contained continuous reinforcing bars(MC and HC) and the slabs with lapped contactsplices are shown in 1047297gures 4(a) and 4(b) Splicelengths are shown as a percentage of L

sytlap

43 Series 2 and 3 tests

In these series the concrete modulus Ec was measured

for each specimen For the slab specimens designatedSS the measured yield strengths of the N12 and N16 bars were 581 and 575 MPa respectively For theslabs designated SL the measured yield strength ofthe N12 bars was 561 MPa For the beam specimensdesignated BL the measured yield strength of theN20 bars was 534 MPa The results of the tests areshown in tables 5 and 6

5 DISCUSSION OF RESULTS

51 Factor of safety Effect of bar diameter

The effect of bar diameter on the FoS is illustratedin 1047297gure 5 where the FoS for all the contact lappedsplices is plotted against bar diameter While thefactors of safety associated with the AS3600-2009provisions are satisfactory for the smaller diameter bars in the Series 1 and 2 slab specimens (10-16 mm)the values for the (Series 3) beam tests (20 mm) are

unsatisfactorily low The effect of bar diameter inthe speci1047297ed lap length in AS3600-2009 appears to be rather poorly calibrated

52 Factor of safety Contact versusnon-contact splices

Figures 6 and 7 show the lap length versus FoS for both the contact and non-contact lapped splices ofthe N12 bars

It is noted that for the contact splices the lap lengthspeci1047297ed by AS3600-2009 is 125L

syt while for the

non-contact splices the speci1047297ed lap length is Lsyt + 15s

b for the Series 1 tests where s

b is relatively

large and 125Lsyt

for the Series 2 tests where sb is

relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149

Continuous bars100102

6648

Figure 4 Ductility of slabs from Series 1 as afunction of splice length ndash (a) mediumstrength concrete specimens Mand (b) high strength concretespecimens H

0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety

B a r d i a m e t e r d b

[ m m ] FoS = 167

Series 1 Series 2

Series 3

Figure 5 Effect of bar diameter on FoS inAS3600-2009

There appears to be no signi1047297cant difference betweenthe factors of safety for the contact and non-contactsplices However the graph shown in 1047297gure 8 suggeststhat the highly eccentric non-contact splices in Series 1are about 10 weaker than the contact splices This isnot true of the non-contact Series 2 splices where s

b was

relatively small and where no signi1047297cant differenceswere observed (see 1047297gure 7) This is not intuitivelyobvious Intuitively with the full perimeter of each bar

within the non-contact lap length able to bond withthe surrounding concrete one would expect a higherstrength than a contact splice of the same length Thiswas in fact observed in SL-8

(a)

(b)



43



There is a very significant decrease in f ub

withincreasing anchorage length When flexuralcracking occurs the bond between the bar andthe concrete is broken locally in the immediatevicinity of a crack When the lap length is increaseda larger number of primary cracks occur withinthe longer lap length and as a consequence theaverage ultimate bond stress over the length of the

lap is lower The speci1047297ed lap lengths in codes ofpractice have generally been based on test resultsfrom specimens with relatively small laps and suchan approach is unconservative

54 Ultimate bond stress Effect oftransverse reinforcement

Figure 10 illustrates the effect of transversereinforcement ( A

trs) on the average ultimate

bond stress The increase in f ub

due to the inclusionof transverse reinforcement is apparent and is

consistent with the way the beneficial effect oftransverse reinforcement is included in AS3600-2009(which is identical to the approach in Eurocode 2(CEN 1992))

0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact

A c t u a l l a p l e n g t h

L l a p

[ m m ]

Figure 6 FoS for contact and non-contactsplices (N12 bars) Series 1

0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10

Proportion of M u (ie M max M u)


L l a p

[ m m ]

Contact

Non-contact

Figure 8 Strength of contact and non-contactsplices (N12 bars) Series 1

53 Ultimate bond stress Effect of lap length

Figure 9 shows the average ultimate bond stress f ub

versus the lap length L

lap for the N12 contact lapped

splices of the slab tests of Series 1 and 2 The averageultimate bond stress is calculated from the maximumsteel stress in the spliced bar using

st s

ubb lap

A

f d L

(3)

where As is the cross-sectional area of spliced bar of

diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300

Contact N12 ndash Series 2


Lap length Llap [mm] A v e r a g e u l t i m a

t e b o n d s t r e s s

f u b [ M

P a ]

Figure 9 Decrease in average ultimate bondstress with increasing lap length ndashN12 bars contact splices

0

1

2

3

4

5

6

0

05

1 15 2

Transverse reinforcement along lap length tr s [mm]

A v e r a g e u l t i m a t e b o n d s t r e s s

f u b

[ M P a ]

Figure 10 Bene1047297cial effect of transversereinforcement Series 3



44



55 Factor of safety Effect of cyclicand sustained loads

Comparing Mmax

on identical specimens subjectedto static cyclic and sustained loading in the testsof Series 2 and 3 there appears to be no signi1047297cantreduction in the capacity of the lap splice due to cyclic

or sustained loading Indeed for SL-8 after 10 monthsof drying under load there was a substantial increasein the FoS Additional testing is currently beingplanned to further examine this aspect of the project

56 Ductility of lap splice

Referring to 1047297gures 3 and 4 all four of the slabswith 100 laps did not achieve the same strengthnor the same ductility as the slabs reinforced withcontinuous bars but the slabs with 150 laps didachieve the same strength For the slabs with medium

strength concrete those with the 150 laps providedthe same ductility as the slabs reinforced with thecontinuous bars However for the slabs with highstrength concrete those with the 150 laps did notprovide the same ductility as the slabs reinforcedwith the continuous bars The results do suggest thatthe FoS of 1 = 167 is necessary and suf1047297cient foradequate strength of the splice For medium strengthconcrete this may also be suf1047297cient for adequateductility as well

6 CONCLUSIONS

A limited number of tests on slabs containing lappedsplices have been conducted in order to study theadequacy of their strength and ductility under loadand deformation The load at which bond failureoccurs depends among other factors on the spacingof primary cracks within the lap length The averageultimate bond stress that develops at failure in alap length is not only heavily dependent on the bardiameter but is also dependent on the number ofcracks that cross the lap The specimens in whichL

lap was small had a small number of primary cracks

within the lap length sometimes no cracks at all alongL

lap and the average ultimate bond stress determined

from the load at failure was high To properly studythese effects a number of identical specimens willneed to be tested to assess the variability of the resultsand the in1047298uence of crack location and spacing Thesetests are currently being planned

It is noted that the value of Lsytlap

speci1047297ed in AS3600-2009 has been calibrated from tests on relatively shortanchorage lengths in the range 10d

b to 25d

b where

average ultimate bond stresses may be signi1047297cantlyhigher than for an anchorage length in the range 35d

b

to 50db (the typical range for Lsytlap) Notwithstandingthe above the factors of safety in relation to thepredicted stress development obtained using theprocedure in AS3600-2009 were unsatisfactorily low

in all of the lapped splice beam specimens (withN20 bars) but acceptable for all slab specimenscontaining smaller diameter bars This requiresfurther investigation

For splices consistent with AS3600-2009 lap lengthsin medium strength concrete may provide ductilitysimilar to that achieved if the bars were instead

continuous but this may not be the case in higherstrength concrete This important aspect requiresfurther examination

ACKNOWLEDGEMENT

The experimental work was conducted with theassistance of students and technical staff at bothLa Trobe University Australia and the Universityof New South Wales and their support is gratefullyacknowledged The tests at UNSW were undertaken

with the financial support of the AustralianResearch Council through an ARC Discovery grantDP1096560 to the 1047297rst author This support is alsogratefully acknowledged

REFERENCES

Bilston B amp Burke A 2011 ldquoThe Strength andDuctility of Steel Tensile Splices in High StrengthConcreterdquo Investigation Project Report CivilEngineering La Trobe University November

CEN 1992 Eurocode 2 Design of concrete structuresPart 1-1 General rules for buildings DD ENV 1992-1-1European Committee for Standardisation Brussels

Duke C amp Trask L 2011 ldquoThe Strength andDuctility of Steel Tensile Splices in ConcreterdquoInvestigation Project Report Civil Engineering LaTrobe University November

Gilbert R I Chang Z-T amp Mazumder M 2011ldquoAnchorage of reinforcement in concrete structures

subjected to cyclic loadingrdquo CONCRETE 1125th Biennial Conference of Concrete Institute ofAustralia October Perth

Gilbert R I Mazumder M amp Chang Z-T 2012ldquoBond slip and cracking within the anchoragelength of deformed reinforcing bars in tensionrdquo4th International Symposium on Bond in ConcreteBrescia Italy June

Haw T amp Leskovec C 2010 ldquoSteel Tensile Splices inHigh Strength Concreterdquo Investigation Project Report

Civil Engineering La Trobe University November

Kim T H Kim B S Chund Y S amp Shim H M2006 ldquoSeismic performance assessment of reinforced



45



concrete bridge piers with lap splicesrdquo EngineeringStructures Vol 26 No 6 pp 935-945

Mitchell C amp Sheppard N 2010 ldquoSteel TensileSplices in High Strength Concreterdquo InvestigationProject Report Civil Engineering La Trobe UniversityNovember

Russo G Pauletta M amp Mitri D 2009 ldquoSolutionfor bond distribution in asymmetric RC structuralmembersrdquo Engineering Structures Vol 31 No 4 pp968-975

Standards Australia 2009 AS3600-2009 Australianstandard for concrete structures Sydney

Wang H 2009 ldquoAn analytical study of bondstrength associated with splitting of concrete coverrdquoEngineering Structures Vol 31 No 3 pp 633-641

Yeow J X 2008 ldquoThe Development Length andLapped Splice Length in Reinforced ConcreterdquoBachelor of Engineering Honours Thesis Universityof New South Wales November



46



IAN GILBERT

Ian Gilbert (FIEAust) is Emeritus Professor of Civil Engineering at the Universityof New South Wales (UNSW) He is Deputy Director of the UNSW Centrefor Infrastructure Engineering and Safety and has over 40 yearsrsquo experienceworking both in academia and as a consultant to the concrete industry His mainresearch interests are in the area of serviceability of reinforced and prestressed

concrete structures He has published six books and over 300 papers in refereed journals and conferences Ian has been actively involved in the development ofthe Australian Standard AS3600 for over 30 years

ANDREW KILPATRICK

Dr Andrew Kilpatrick is an Honorary Associate in the Department of CivilEngineering at La Trobe University Victoria and has been actively involved inthe design teaching and research of reinforced concrete for over 35 years Hehas been a member of Standards Australia Committee BD-002 for the last 12years and is a co-author of the textbook Reinforced Concrete Basics



35

Paper S13-033 submitted 110913 accepted for publicationafter review and revision 260214

dagger Corresponding author EProf Ian Gilbert can be contacted atigilbertunsweduau

technical paper

The strength and ductility of lapped

splices of reinforcing bars in tension

RI Gilbertdagger

School of Civil and Environmental Engineering The University of New South Wales Sydney NSW

AE KilpatrickLa Trobe University Bendigo Victoria

ABSTRACT When designing a reinforced concrete member for strength ductility and robustnessit is essential that the tensile reinforcement at the critical section can not only develop the yieldstrength of the steel f

sy but that it can sustain this level of stress as deformation increases At a lapped

splice each bar must be fully anchored beyond the lap length The minimum lap lengths of deformedreinforcing bars in tension speci1047297ed in the Australian Standard for Concrete Structures AS3600-2009 were recently revised and a procedure similar to but less conservative than the provisionsin Eurocode 2 was adopted The new provisions require longer lap lengths for small diameter barsin slabs but considerably shorter lap lengths for larger diameter bars in beams and columns This paper reports on several series of tests that examine the ef1047297cacy of the AS 3600-2009 provisions fromthe perspectives of adequate strength and ductility Over 50 specimens containing both contact andnon-contact lapped splices have been tested The aim was to assess the current Australian provisionsand to examine the reliability and consistency of the factors of safety associated with lapped splicesIt is concluded that the strength requirements of AS3600-2009 are adequate for small diameter barsin slabs but may not provide an adequate factor of safety for large diameter bars in beams Also the

AS3600 provisions may not ensure suf1047297cient ductility of a lapped splice in members that use highstrength concrete Further tests are required to investigate these aspects

KEYWORDS Anchorage bond deformed bars development length ductility factor ofsafety lapped splice reinforced concrete ultimate strength

REFERENCE Gilbert R I amp Kilpatrick A E 2015 ldquoThe strength and ductility of lappedsplices of reinforcing bars in tensionrdquo Australian Journal of Structural Engineering Vol 16No 1 January pp 35-46 httpdxdoiorg107158S13-0332015161

1 INTRODUCTION

Reinforcing bars are normally supplied in lengthsof 6 m or so In members longer than this full stresstransfer from one bar to another is achieved by eitherwelding the bars together or by using mechanicalsplices or by lapping the bars over a nominateddistance (a structural lapped splice) In the lattercase each bar in the splice must be fully anchored beyond the lap length

This paper reports on an experimental programdesigned to examine the strength and deformation behaviour of lapped splices of reinforcing barsin tension and to assess the efficacy of the newprovisions for lapped splices in the AustralianStandard for Concrete Structures AS 3600-2009(Standards Australia 2009) from the perspectivesof adequate strength and ductility The differences in behaviour of contact and non-contact lapped splicesare examined and the impact of cyclic loading on the

anchorage requirements of reinforcing bars is alsoconsidered The long-term aim of this research isto develop procedures for anchoring reinforcementin concrete structures that provide reliable and

copy Institution of Engineers Australia 2015 Australian Journal of Structural Engineering Vol 16 No 1



36























ub decreases

3 500 = 1500

100

Elevation

420

100

a

c

c1a

a

100

420

100

3 500 = 1500


a

c

c1

Plan Section

Non-contact splice






1 3

1

2

292

sy b

sy tb b

c

k k f dL k d

k f

(1)


1 =

10 k 2 = (132 ndash d

b)100 k

3 = 10 ndash 015(c

d ndash d

b)d

b (but

07 le k 3 le 10) c





b = diameter






) or where


Lsyt

= k 4k

5L

sytb (2)


4 le 10) k

5 = 10 ndash 004

p

(but 07 le k 5 le 10) = ( A

tr ndash A

trmin) A

s A

tr


trmin




37





s = cross-sectional








st f

sy



syt or L

syt + 15s

b whichever



Llap

100

600 600

600

150

P P

850

Llap

sb




(a)

(b)

(c)

(d)


31 Series 1 tests







1 =




32 Series 2 tests







38





cm [MPa] d


b [mm] c [mm]

MC1 C 86 226 549 12 184 284 0 12

MNC1 NC 86 226 567 12 186 194 91 12

MC2 C 86 226 571 12 132 284 0 12

MNC2 NC 86 226 553 12 133 194 91 12

MC3 C 61 226 538 12 127 284 0 36

MNC3 NC 62 226 530 12 128 194 91 36

MC4 C 62 226 566 12 89 284 0 36

MNC4 NC 61 226 541 12 87 194 91 36

HC1 C 85 226 591 12 165 284 0 12

HNC1 NC 85 226 625 12 165 194 91 12

HC2 C 85 226 639 12 118 284 0 12

HNC2 NC 83 226 632 12 115 194 91 12

HC3 C 64 226 546 12 116 284 ndash 36

HNC3 NC 61 226 546 12 117 194 91 36

HN4 C 61 226 602 12 81 284 ndash 36

HNC4 NC 62 226 555 12 80 194 91 36

M30 C 75 157 320 10 82 290 0 20

M45 C 75 157 320 10 122 290 0 20

M60 C 75 157 328 10 160 290 0 20

M100A C 75 157 362 10 261 290 0 21

M100B C 75 157 369 10 263 290 0 22M150A C 75 157 343 10 397 290 0 22

M150B C 75 157 340 10 395 290 0 22


H30 C 74 226 823 12 67 284 0 20

H45 C 74 226 741 12 104 284 0 20

H60 C 74 226 782 12 138 284 0 20

H100A C 74 226 703 12 222 284 0 20

H100B C 74 226 703 12 226 284 0 20

H150A C 74 226 711 12 328 284 0 20H150B C 74 226 727 12 337 284 0 20






32 Series 3 tests





39




sb = 28 mm)


cm [MPa] d


b [mm] c [mm]

SS-1 C 119 452 12 318 150 125 180 25

SS-2 C 119 452 12 343 220 125 180 25

SS-3 C 119 339 12 343 150 125 276 25SS-4 C 119 339 12 348 220 125 276 25

SS-5 C 117 804 16 348 200 125 173 25

SS-6 C 117 804 16 352 280 125 173 25

SS-7 C 117 603 16 352 200 125 268 25

SS-8 C 117 603 16 356 280 125 268 25

SS-9 C 104 452 12 356 150 125 180 40

SS-10 C 104 339 12 369 220 125 276 40

SL-1 C 119 452 12 380 120 120 188 25

SL-2 C 119 452 12 380 180 120 188 25SL-3 C 119 452 12 380 240 120 188 25

SL-4 C 119 452 12 380 180 120 188 25

SL-5^ C 119 452 12 380 180 120 188 25

SL-6 NC 119 452 12 380 180 120 188 25

SL-7 NC 119 452 12 380 180 120 188 25



P P

Atr

150

300

Llap

100 700

700 700

2

N12

bars

300

250

2 N20 bars

(spliced)





trs) where A




4 TEST RESULTS









AS3600-2009 as 125Lsyt


(a) (b)



40





b [mm] A

tr s [mm] f

cm [MPa] Lap [mm] c


BL-1 265 628 20 000 430 300 35 120 25

BL-2 265 628 20 000 430 400 35 120 25

BL-3 265 628 20 000 430 300 35 120 25

BL-4 265 628 20 157 430 300 35 120 25

BL-5 265 628 20 157 430 300 35 120 25

BL-6 265 628 20 105 430 300 35 120 25



Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

MC1 226 184 755 33900 693 422 356 065 193

MNC1 226 186 685 34200 688 383 347 060 187MC2 226 132 605 34300 686 338 279 047 212

MNC2 226 133 540 33900 693 302 276 043 208

MC3 226 127 508 33700 328 406 242 063 191

MNC3 226 128 451 33500 342 354 257 052 201

MC4 226 89 397 34200 336 312 181 046 204

MNC4 226 87 375 33700 328 300 216 037 248

HC1 226 165 693 34600 664 392 318 060 193

HNC1 226 165 631 35200 655 356 312 056 189

HC2 226 118 577 35500 650 326 255 045 216

HNC2 226 115 441 35300 620 255 223 040 194

HC3 226 116 498 33800 364 378 224 058 193

HNC3 226 117 441 33800 328 352 253 048 216

HN4 226 81 433 34800 320 345 195 043 240

HNC4 226 80 408 34000 338 320 229 034 286

M30 157 82 303 27700 450 279 215 029 262

M45 157 122 435 27700 450 401 309 044 253

M60 157 160 500 28000 446 460 350 058 219




H30 226 67 410 38400 451 267 165 033 247

H45 226 104 603 37200 463 392 256 048 247

H60 226 138 640 37800 457 416 265 066 192





Mean 222





41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216




Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128













42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




36























ub decreases

3 500 = 1500

100

Elevation

420

100

a

c

c1a

a

100

420

100

3 500 = 1500


a

c

c1

Plan Section

Non-contact splice






1 3

1

2

292

sy b

sy tb b

c

k k f dL k d

k f

(1)


1 =

10 k 2 = (132 ndash d

b)100 k

3 = 10 ndash 015(c

d ndash d

b)d

b (but

07 le k 3 le 10) c





b = diameter






) or where


Lsyt

= k 4k

5L

sytb (2)


4 le 10) k

5 = 10 ndash 004

p

(but 07 le k 5 le 10) = ( A

tr ndash A

trmin) A

s A

tr


trmin




37





s = cross-sectional








st f

sy



syt or L

syt + 15s

b whichever



Llap

100

600 600

600

150

P P

850

Llap

sb




(a)

(b)

(c)

(d)


31 Series 1 tests







1 =




32 Series 2 tests







38





cm [MPa] d


b [mm] c [mm]

MC1 C 86 226 549 12 184 284 0 12

MNC1 NC 86 226 567 12 186 194 91 12

MC2 C 86 226 571 12 132 284 0 12

MNC2 NC 86 226 553 12 133 194 91 12

MC3 C 61 226 538 12 127 284 0 36

MNC3 NC 62 226 530 12 128 194 91 36

MC4 C 62 226 566 12 89 284 0 36

MNC4 NC 61 226 541 12 87 194 91 36

HC1 C 85 226 591 12 165 284 0 12

HNC1 NC 85 226 625 12 165 194 91 12

HC2 C 85 226 639 12 118 284 0 12

HNC2 NC 83 226 632 12 115 194 91 12

HC3 C 64 226 546 12 116 284 ndash 36

HNC3 NC 61 226 546 12 117 194 91 36

HN4 C 61 226 602 12 81 284 ndash 36

HNC4 NC 62 226 555 12 80 194 91 36

M30 C 75 157 320 10 82 290 0 20

M45 C 75 157 320 10 122 290 0 20

M60 C 75 157 328 10 160 290 0 20

M100A C 75 157 362 10 261 290 0 21

M100B C 75 157 369 10 263 290 0 22M150A C 75 157 343 10 397 290 0 22

M150B C 75 157 340 10 395 290 0 22


H30 C 74 226 823 12 67 284 0 20

H45 C 74 226 741 12 104 284 0 20

H60 C 74 226 782 12 138 284 0 20

H100A C 74 226 703 12 222 284 0 20

H100B C 74 226 703 12 226 284 0 20

H150A C 74 226 711 12 328 284 0 20H150B C 74 226 727 12 337 284 0 20






32 Series 3 tests





39




sb = 28 mm)


cm [MPa] d


b [mm] c [mm]

SS-1 C 119 452 12 318 150 125 180 25

SS-2 C 119 452 12 343 220 125 180 25

SS-3 C 119 339 12 343 150 125 276 25SS-4 C 119 339 12 348 220 125 276 25

SS-5 C 117 804 16 348 200 125 173 25

SS-6 C 117 804 16 352 280 125 173 25

SS-7 C 117 603 16 352 200 125 268 25

SS-8 C 117 603 16 356 280 125 268 25

SS-9 C 104 452 12 356 150 125 180 40

SS-10 C 104 339 12 369 220 125 276 40

SL-1 C 119 452 12 380 120 120 188 25

SL-2 C 119 452 12 380 180 120 188 25SL-3 C 119 452 12 380 240 120 188 25

SL-4 C 119 452 12 380 180 120 188 25

SL-5^ C 119 452 12 380 180 120 188 25

SL-6 NC 119 452 12 380 180 120 188 25

SL-7 NC 119 452 12 380 180 120 188 25



P P

Atr

150

300

Llap

100 700

700 700

2

N12

bars

300

250

2 N20 bars

(spliced)





trs) where A




4 TEST RESULTS









AS3600-2009 as 125Lsyt


(a) (b)



40





b [mm] A

tr s [mm] f

cm [MPa] Lap [mm] c


BL-1 265 628 20 000 430 300 35 120 25

BL-2 265 628 20 000 430 400 35 120 25

BL-3 265 628 20 000 430 300 35 120 25

BL-4 265 628 20 157 430 300 35 120 25

BL-5 265 628 20 157 430 300 35 120 25

BL-6 265 628 20 105 430 300 35 120 25



Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

MC1 226 184 755 33900 693 422 356 065 193

MNC1 226 186 685 34200 688 383 347 060 187MC2 226 132 605 34300 686 338 279 047 212

MNC2 226 133 540 33900 693 302 276 043 208

MC3 226 127 508 33700 328 406 242 063 191

MNC3 226 128 451 33500 342 354 257 052 201

MC4 226 89 397 34200 336 312 181 046 204

MNC4 226 87 375 33700 328 300 216 037 248

HC1 226 165 693 34600 664 392 318 060 193

HNC1 226 165 631 35200 655 356 312 056 189

HC2 226 118 577 35500 650 326 255 045 216

HNC2 226 115 441 35300 620 255 223 040 194

HC3 226 116 498 33800 364 378 224 058 193

HNC3 226 117 441 33800 328 352 253 048 216

HN4 226 81 433 34800 320 345 195 043 240

HNC4 226 80 408 34000 338 320 229 034 286

M30 157 82 303 27700 450 279 215 029 262

M45 157 122 435 27700 450 401 309 044 253

M60 157 160 500 28000 446 460 350 058 219




H30 226 67 410 38400 451 267 165 033 247

H45 226 104 603 37200 463 392 256 048 247

H60 226 138 640 37800 457 416 265 066 192





Mean 222





41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216




Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128













42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




37





s = cross-sectional








st f

sy



syt or L

syt + 15s

b whichever



Llap

100

600 600

600

150

P P

850

Llap

sb




(a)

(b)

(c)

(d)


31 Series 1 tests







1 =




32 Series 2 tests







38





cm [MPa] d


b [mm] c [mm]

MC1 C 86 226 549 12 184 284 0 12

MNC1 NC 86 226 567 12 186 194 91 12

MC2 C 86 226 571 12 132 284 0 12

MNC2 NC 86 226 553 12 133 194 91 12

MC3 C 61 226 538 12 127 284 0 36

MNC3 NC 62 226 530 12 128 194 91 36

MC4 C 62 226 566 12 89 284 0 36

MNC4 NC 61 226 541 12 87 194 91 36

HC1 C 85 226 591 12 165 284 0 12

HNC1 NC 85 226 625 12 165 194 91 12

HC2 C 85 226 639 12 118 284 0 12

HNC2 NC 83 226 632 12 115 194 91 12

HC3 C 64 226 546 12 116 284 ndash 36

HNC3 NC 61 226 546 12 117 194 91 36

HN4 C 61 226 602 12 81 284 ndash 36

HNC4 NC 62 226 555 12 80 194 91 36

M30 C 75 157 320 10 82 290 0 20

M45 C 75 157 320 10 122 290 0 20

M60 C 75 157 328 10 160 290 0 20

M100A C 75 157 362 10 261 290 0 21

M100B C 75 157 369 10 263 290 0 22M150A C 75 157 343 10 397 290 0 22

M150B C 75 157 340 10 395 290 0 22


H30 C 74 226 823 12 67 284 0 20

H45 C 74 226 741 12 104 284 0 20

H60 C 74 226 782 12 138 284 0 20

H100A C 74 226 703 12 222 284 0 20

H100B C 74 226 703 12 226 284 0 20

H150A C 74 226 711 12 328 284 0 20H150B C 74 226 727 12 337 284 0 20






32 Series 3 tests





39




sb = 28 mm)


cm [MPa] d


b [mm] c [mm]

SS-1 C 119 452 12 318 150 125 180 25

SS-2 C 119 452 12 343 220 125 180 25

SS-3 C 119 339 12 343 150 125 276 25SS-4 C 119 339 12 348 220 125 276 25

SS-5 C 117 804 16 348 200 125 173 25

SS-6 C 117 804 16 352 280 125 173 25

SS-7 C 117 603 16 352 200 125 268 25

SS-8 C 117 603 16 356 280 125 268 25

SS-9 C 104 452 12 356 150 125 180 40

SS-10 C 104 339 12 369 220 125 276 40

SL-1 C 119 452 12 380 120 120 188 25

SL-2 C 119 452 12 380 180 120 188 25SL-3 C 119 452 12 380 240 120 188 25

SL-4 C 119 452 12 380 180 120 188 25

SL-5^ C 119 452 12 380 180 120 188 25

SL-6 NC 119 452 12 380 180 120 188 25

SL-7 NC 119 452 12 380 180 120 188 25



P P

Atr

150

300

Llap

100 700

700 700

2

N12

bars

300

250

2 N20 bars

(spliced)





trs) where A




4 TEST RESULTS









AS3600-2009 as 125Lsyt


(a) (b)



40





b [mm] A

tr s [mm] f

cm [MPa] Lap [mm] c


BL-1 265 628 20 000 430 300 35 120 25

BL-2 265 628 20 000 430 400 35 120 25

BL-3 265 628 20 000 430 300 35 120 25

BL-4 265 628 20 157 430 300 35 120 25

BL-5 265 628 20 157 430 300 35 120 25

BL-6 265 628 20 105 430 300 35 120 25



Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

MC1 226 184 755 33900 693 422 356 065 193

MNC1 226 186 685 34200 688 383 347 060 187MC2 226 132 605 34300 686 338 279 047 212

MNC2 226 133 540 33900 693 302 276 043 208

MC3 226 127 508 33700 328 406 242 063 191

MNC3 226 128 451 33500 342 354 257 052 201

MC4 226 89 397 34200 336 312 181 046 204

MNC4 226 87 375 33700 328 300 216 037 248

HC1 226 165 693 34600 664 392 318 060 193

HNC1 226 165 631 35200 655 356 312 056 189

HC2 226 118 577 35500 650 326 255 045 216

HNC2 226 115 441 35300 620 255 223 040 194

HC3 226 116 498 33800 364 378 224 058 193

HNC3 226 117 441 33800 328 352 253 048 216

HN4 226 81 433 34800 320 345 195 043 240

HNC4 226 80 408 34000 338 320 229 034 286

M30 157 82 303 27700 450 279 215 029 262

M45 157 122 435 27700 450 401 309 044 253

M60 157 160 500 28000 446 460 350 058 219




H30 226 67 410 38400 451 267 165 033 247

H45 226 104 603 37200 463 392 256 048 247

H60 226 138 640 37800 457 416 265 066 192





Mean 222





41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216




Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128













42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




38





cm [MPa] d


b [mm] c [mm]

MC1 C 86 226 549 12 184 284 0 12

MNC1 NC 86 226 567 12 186 194 91 12

MC2 C 86 226 571 12 132 284 0 12

MNC2 NC 86 226 553 12 133 194 91 12

MC3 C 61 226 538 12 127 284 0 36

MNC3 NC 62 226 530 12 128 194 91 36

MC4 C 62 226 566 12 89 284 0 36

MNC4 NC 61 226 541 12 87 194 91 36

HC1 C 85 226 591 12 165 284 0 12

HNC1 NC 85 226 625 12 165 194 91 12

HC2 C 85 226 639 12 118 284 0 12

HNC2 NC 83 226 632 12 115 194 91 12

HC3 C 64 226 546 12 116 284 ndash 36

HNC3 NC 61 226 546 12 117 194 91 36

HN4 C 61 226 602 12 81 284 ndash 36

HNC4 NC 62 226 555 12 80 194 91 36

M30 C 75 157 320 10 82 290 0 20

M45 C 75 157 320 10 122 290 0 20

M60 C 75 157 328 10 160 290 0 20

M100A C 75 157 362 10 261 290 0 21

M100B C 75 157 369 10 263 290 0 22M150A C 75 157 343 10 397 290 0 22

M150B C 75 157 340 10 395 290 0 22


H30 C 74 226 823 12 67 284 0 20

H45 C 74 226 741 12 104 284 0 20

H60 C 74 226 782 12 138 284 0 20

H100A C 74 226 703 12 222 284 0 20

H100B C 74 226 703 12 226 284 0 20

H150A C 74 226 711 12 328 284 0 20H150B C 74 226 727 12 337 284 0 20






32 Series 3 tests





39




sb = 28 mm)


cm [MPa] d


b [mm] c [mm]

SS-1 C 119 452 12 318 150 125 180 25

SS-2 C 119 452 12 343 220 125 180 25

SS-3 C 119 339 12 343 150 125 276 25SS-4 C 119 339 12 348 220 125 276 25

SS-5 C 117 804 16 348 200 125 173 25

SS-6 C 117 804 16 352 280 125 173 25

SS-7 C 117 603 16 352 200 125 268 25

SS-8 C 117 603 16 356 280 125 268 25

SS-9 C 104 452 12 356 150 125 180 40

SS-10 C 104 339 12 369 220 125 276 40

SL-1 C 119 452 12 380 120 120 188 25

SL-2 C 119 452 12 380 180 120 188 25SL-3 C 119 452 12 380 240 120 188 25

SL-4 C 119 452 12 380 180 120 188 25

SL-5^ C 119 452 12 380 180 120 188 25

SL-6 NC 119 452 12 380 180 120 188 25

SL-7 NC 119 452 12 380 180 120 188 25



P P

Atr

150

300

Llap

100 700

700 700

2

N12

bars

300

250

2 N20 bars

(spliced)





trs) where A




4 TEST RESULTS









AS3600-2009 as 125Lsyt


(a) (b)



40





b [mm] A

tr s [mm] f

cm [MPa] Lap [mm] c


BL-1 265 628 20 000 430 300 35 120 25

BL-2 265 628 20 000 430 400 35 120 25

BL-3 265 628 20 000 430 300 35 120 25

BL-4 265 628 20 157 430 300 35 120 25

BL-5 265 628 20 157 430 300 35 120 25

BL-6 265 628 20 105 430 300 35 120 25



Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

MC1 226 184 755 33900 693 422 356 065 193

MNC1 226 186 685 34200 688 383 347 060 187MC2 226 132 605 34300 686 338 279 047 212

MNC2 226 133 540 33900 693 302 276 043 208

MC3 226 127 508 33700 328 406 242 063 191

MNC3 226 128 451 33500 342 354 257 052 201

MC4 226 89 397 34200 336 312 181 046 204

MNC4 226 87 375 33700 328 300 216 037 248

HC1 226 165 693 34600 664 392 318 060 193

HNC1 226 165 631 35200 655 356 312 056 189

HC2 226 118 577 35500 650 326 255 045 216

HNC2 226 115 441 35300 620 255 223 040 194

HC3 226 116 498 33800 364 378 224 058 193

HNC3 226 117 441 33800 328 352 253 048 216

HN4 226 81 433 34800 320 345 195 043 240

HNC4 226 80 408 34000 338 320 229 034 286

M30 157 82 303 27700 450 279 215 029 262

M45 157 122 435 27700 450 401 309 044 253

M60 157 160 500 28000 446 460 350 058 219




H30 226 67 410 38400 451 267 165 033 247

H45 226 104 603 37200 463 392 256 048 247

H60 226 138 640 37800 457 416 265 066 192





Mean 222





41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216




Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128













42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




39




sb = 28 mm)


cm [MPa] d


b [mm] c [mm]

SS-1 C 119 452 12 318 150 125 180 25

SS-2 C 119 452 12 343 220 125 180 25

SS-3 C 119 339 12 343 150 125 276 25SS-4 C 119 339 12 348 220 125 276 25

SS-5 C 117 804 16 348 200 125 173 25

SS-6 C 117 804 16 352 280 125 173 25

SS-7 C 117 603 16 352 200 125 268 25

SS-8 C 117 603 16 356 280 125 268 25

SS-9 C 104 452 12 356 150 125 180 40

SS-10 C 104 339 12 369 220 125 276 40

SL-1 C 119 452 12 380 120 120 188 25

SL-2 C 119 452 12 380 180 120 188 25SL-3 C 119 452 12 380 240 120 188 25

SL-4 C 119 452 12 380 180 120 188 25

SL-5^ C 119 452 12 380 180 120 188 25

SL-6 NC 119 452 12 380 180 120 188 25

SL-7 NC 119 452 12 380 180 120 188 25



P P

Atr

150

300

Llap

100 700

700 700

2

N12

bars

300

250

2 N20 bars

(spliced)





trs) where A




4 TEST RESULTS









AS3600-2009 as 125Lsyt


(a) (b)



40





b [mm] A

tr s [mm] f

cm [MPa] Lap [mm] c


BL-1 265 628 20 000 430 300 35 120 25

BL-2 265 628 20 000 430 400 35 120 25

BL-3 265 628 20 000 430 300 35 120 25

BL-4 265 628 20 157 430 300 35 120 25

BL-5 265 628 20 157 430 300 35 120 25

BL-6 265 628 20 105 430 300 35 120 25



Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

MC1 226 184 755 33900 693 422 356 065 193

MNC1 226 186 685 34200 688 383 347 060 187MC2 226 132 605 34300 686 338 279 047 212

MNC2 226 133 540 33900 693 302 276 043 208

MC3 226 127 508 33700 328 406 242 063 191

MNC3 226 128 451 33500 342 354 257 052 201

MC4 226 89 397 34200 336 312 181 046 204

MNC4 226 87 375 33700 328 300 216 037 248

HC1 226 165 693 34600 664 392 318 060 193

HNC1 226 165 631 35200 655 356 312 056 189

HC2 226 118 577 35500 650 326 255 045 216

HNC2 226 115 441 35300 620 255 223 040 194

HC3 226 116 498 33800 364 378 224 058 193

HNC3 226 117 441 33800 328 352 253 048 216

HN4 226 81 433 34800 320 345 195 043 240

HNC4 226 80 408 34000 338 320 229 034 286

M30 157 82 303 27700 450 279 215 029 262

M45 157 122 435 27700 450 401 309 044 253

M60 157 160 500 28000 446 460 350 058 219




H30 226 67 410 38400 451 267 165 033 247

H45 226 104 603 37200 463 392 256 048 247

H60 226 138 640 37800 457 416 265 066 192





Mean 222





41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216




Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128













42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




40





b [mm] A

tr s [mm] f

cm [MPa] Lap [mm] c


BL-1 265 628 20 000 430 300 35 120 25

BL-2 265 628 20 000 430 400 35 120 25

BL-3 265 628 20 000 430 300 35 120 25

BL-4 265 628 20 157 430 300 35 120 25

BL-5 265 628 20 157 430 300 35 120 25

BL-6 265 628 20 105 430 300 35 120 25



Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

MC1 226 184 755 33900 693 422 356 065 193

MNC1 226 186 685 34200 688 383 347 060 187MC2 226 132 605 34300 686 338 279 047 212

MNC2 226 133 540 33900 693 302 276 043 208

MC3 226 127 508 33700 328 406 242 063 191

MNC3 226 128 451 33500 342 354 257 052 201

MC4 226 89 397 34200 336 312 181 046 204

MNC4 226 87 375 33700 328 300 216 037 248

HC1 226 165 693 34600 664 392 318 060 193

HNC1 226 165 631 35200 655 356 312 056 189

HC2 226 118 577 35500 650 326 255 045 216

HNC2 226 115 441 35300 620 255 223 040 194

HC3 226 116 498 33800 364 378 224 058 193

HNC3 226 117 441 33800 328 352 253 048 216

HN4 226 81 433 34800 320 345 195 043 240

HNC4 226 80 408 34000 338 320 229 034 286

M30 157 82 303 27700 450 279 215 029 262

M45 157 122 435 27700 450 401 309 044 253

M60 157 160 500 28000 446 460 350 058 219




H30 226 67 410 38400 451 267 165 033 247

H45 226 104 603 37200 463 392 256 048 247

H60 226 138 640 37800 457 416 265 066 192





Mean 222





41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216




Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128













42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




41




Slab A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

SS-1 452 150 192 26000 350 387 359 048 239

SS-2 452 220 265 28400 325 532 475 073 216

SS-3 339 150 153 28400 254 406 363 050 242

SS-4 339 220 191 28700 252 506 449 074 204

SS-5 804 200 256 28700 497 301 402 044 201

SS-6 804 280 301 29100 492 353 470 063 168

SS-7 603 200 170 29100 390 263 350 045 175

SS-8 603 280 242 29500 386 374 495 063 177

SS-9 452 150 180 29500 235 415 282 066 188

SS-10 339 220 178 30700 178 541 362 098 164

SL-1 452 120 174 30500 306 348 296 042 247

SL-2 452 180 244 30500 306 489 415 063 230SL-3 452 240 281 30500 306 563 478 084 199

SL-4a 452 180 260 30500 306 521 442 063 246

SL-5b 452 180 263 30500 306 527 447 063 248

SL-6 452 180 237 30500 306 475 403 058 224

SL-7a 452 180 242 30500 306 485 411 058 229

SL-8b 452 180 301 30500 306 603 512 058 284

Mean 216




Beam A

st

[mm2]Llap

[mm]

M max

[kNm]

Ec

[MPa] I cr

[106 mm4]σ st

[MPa]

AS3600-2009

Lstlap

[mm] Llap

ϕLsytlap

FoS

BL-1 628 300 339 32000 1768 226 369 057 123

BL-2 628 400 466 32000 1768 310 508 076 127

BL-3 628 300 350 32000 1768 233 381 057 127

BL-4 628 300 407 32000 1768 271 388 057 129

BL-5 628 300 428 32000 1768 285 408 057 136

BL-6 628 300 370 32000 1768 246 373 057 124

Mean 128













42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




42




42 Series 1 tests





sytlap











syt while for the



b is relatively

large and 125Lsyt


relatively small

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R a m f o

r c e ( k N )

Continuous bars

29

44

58

101 amp 105

152

151

29

58

101 amp 105

Continuous bars

151

152

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R

a m F

o r c e ( k N )

44

0

5

10

15

20

25

30

35

40

45

0 500 1000 1500 2000 2500 3000 3500

Deflection (divs)

R

a m

f o r c e ( k N )

155149

Continuous bars

100

102

66

48

33

0 5 10 15 20 25 30 35

Deflection mm

40

30

20

10

0

R a m

F o r c e ( k N )

33

155 149


6648


0

5

10

15

20

25

000 050 100 150 200 250 300

Factor of Safety


[ m m ] FoS = 167

Series 1 Series 2

Series 3



b was



(a)

(b)



43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




43












0

40

80

120

160

200

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a p

[ m m ]


0

50

100

150

200

250

300

00 05 10 15 20 25 30

Factor of Safety

Contact

Non-contact


L l a

[ m m ]


0

40

80

120

160

200

00 02

04 06 08 10



L l a p

[ m m ]

Contact

Non-contact







st s

ubb lap

A

f d L

(3)


diameter db

00

20

40

60

80

100

120

140

0 50 100 150 200 250 300





f u b [ M

P a ]


0

1

2

3

4

5

6

0

05

1 15 2



f u b

[ M P a ]




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




44




Comparing Mmax






6 CONCLUSIONS








b to 25d

b where


b





ACKNOWLEDGEMENT



REFERENCES












45











46



IAN GILBERT



ANDREW KILPATRICK




45











46



IAN GILBERT



ANDREW KILPATRICK




46



IAN GILBERT



ANDREW KILPATRICK


Documents

The Strength and Ductility of Lapped Splices of Reinforcing Bars in Tension