ROAD RESEARCH LABORATORY
Ministry of Transport
RRL REPORT LR 223
STATIC TESTS ON STUD ~SHEAR
CONNECTORS IN HAUNCH•ED •SLABS
by
J. S. Teraszkiewicz
Road Research Laboratory Crowthorne, Berkshire
1968
Abstract
1. Introduction
2. Tests
3. Results and discussion
3.1 Concrete strength
3.2 Maximum carrying capacities
3.3 Mode of failure
3.4 Cracks in concrete slabs
.
5.
6.
CONTENTS
3.5 Experiments on push-out specimens without haunches
3.6 Comparison between haunched and plain slab push-out tests
3.7 Proposals for the design of haunches in beams (Fig. 19)
Conclusions
Acknowledgements
References
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CROWN COPYRIGHT 1968
Extracts [rom the text may be" reproduced provided thesource is acknowledged
STATIC TESTS ON STUD SHEAR
CONNECTORS H A U N C H E D SLABS
ABSTRACT
I. INTRODUCTION
/ When a stud shear connector transmits shear at the interface of a composite beam (concrete slab
on steel I-beam) large triaxial s t resses are set up in the concrete near the root of the stud 1
These s t resses occur because of the containment of the concrete by the mass of concrete around
the root of the stud.
In highway bridges it is customary to include haunches between the concrete decks and the
steel beams in order to camber the Carriageway. The degree of containment of the concrete at the
root of stud connectors is thereby reduced and the sides of the haunch are prone to lateral burst-
ing (Fig. 1). The haunch should be designed so that the full potential capacity of the shear
connectors can be achieved.
Tests on shear connectors such as channels which do not cause large local s t resses have
shown that haunches do not appreciably alter the maximum carrying capaci t ies 2 (Fig. 2).
The push-out tests reported have been carried out as a preliminary investigation of shear in haunched beams at Imperial College.
2. TESTS
Four push-out tes ts were carried out on 101.6 x 19.05 mm (4 x ¥4 in) headed studs in specimens with
101.6 mm (4 in) deep haunches, and with concrete cover to studs varying from 19.05 - 50.8 mm (¥4 in
to 2 in). (Fig. 3). In one tes t with 38.1 mm (1~ in) cover, hel ical reinforcement was included around
the studs. Another six push-out tes ts were carried out on 50.8 mm (2 in) deep haunches, with concrete
Cover to studs varying from 19.05 - 76.2 mm (¥4 - 3 in) (Fig. 4). In all the tes t s t ransverse and long '
itudinal reinforcement was positioned only in the s labs . The flanges of the s tee l beams were wire
brushed before casting the concrete. When loads were applied to the specimens no sl ip occurred until
bond was broken. The s l ips shown in Figs. 5 - 14 are those after bond had been broken.
The loads at which cracks appeared in the haunches are shown in Table 1. The first cracks
always appeared at the nosition of thp. studs. At areater loads, cracks appeared in the concrete
, Is. Cracks
'.rences
cracks.
1 been
l e s s
st ing
~.in-
tds w a s
arst
..~,,., ,.m-eu, Iurtaer water cured tes ts were maae.
;n the
th of
ld be
3. RESULTSAND DISCUSSION
3.1 Concrete strength
The relationship between air-and water-cured concrete strengths is shown in Fig. 15. The
tes ts were made at various ages, according to when the push out specimen was tes ted. The age was
usually greater than 14 days. Although there was a large scat ter , the resul ts indicate that the appa-
rent strength of water-cured concrete is slightly less than the air-cured strength. It is probable that
the coefficient of friction at the faces which were compressed was reduced by the water which
squeezed out.
3.2 Maximum carrying capacities
The maximum carrying capaci t ies of the 101.6 x 19.05 (4 x 3/4 in) headed studs used in this
investigation varied from 70 - 101 kN (7.0 tons - 10.1 tons) per stud (Table 3). The lowest capa- city was exhibited by the specimen with a 101.6 mm (4 in) deep haunch having a 19.05 mm (Y4 in)
2
cover, The highest capacity was exhibited by the specimen with a 50.8 mm (2 in) deep haunch
having a cover of 76.2 mm (3 in). The length of the shear surface (Fig. 16) around the studs was
calculated for each specimen and multiplied by the square root of the concrete strength to get a
value of the shear resistance of concrete 3. It was found that, for the tests carried out in this inves-
tigation, the maximum carrying capacity of the studs was proportional to shear resistance of the
concrete (Fig. 16). The specimen with helical reinforcement around the' studs exi~ibited a 10% higher
maximum carrying capacity for a given value of shear surface length and concrete strength, than the
similar specimen without reinforcement, tn an actual beam the shear s t resses in the haunch wou tdbe
limited by the C.P. 117 (Part 2) Recommendations and if bursting and pulling-out can be prevented
the full potential of connectors should be developed.
3.3 Mode of failure
When a cover of less than' 50.8 mm (2 in) was provided, the haunch burst later~illy and the studs
either pulled out of the concrete or sheared after slips greater than 12.7 mm (1/2 in) had occurred. The
maximum load was achieved shortly after bursting of the haunch. The specimen with helical reinforce-
ment around the studs•exhibited less slip than a similar spe6imen without reinforcement, and failure
occurred by crushing of the concrete in front of the studs and shearing of the haunch. The load de-
creased gradually after the maximum had been reached. The part of the haunch behind the studs was
pulled away from the main body of the slab by the heads of the studs 'after the studs had bent backl
A similar mode of failure was exhibited by specimens with covers of 50.8 mm (2 in) or more. The
maximum slip in these specimens was always greater than 12.7 mm (~ in). A sudden •decrease of
load bearing capacity occurred when the studs ,sheared (fig. 9 / 1 0 ).
3.4 Cracks in concrete slabs
First cracks occurred at the position of the studs at loads between 55 and 90 kN (5~ and 9 tonsi
per stud (Table 1 ) . Further cracks occurred in the concrete behind the studs and in the concrete in
front of the studs. The cracks behind the studs were due to the action of the studs in bending back.
Those in front of the studs vqere due to bursting and crushing• of the haunch.
3.5 Experiments on push-out specimens without haunches
Experiments on push-0ut specimens without haunches were carried out. at Imperial College
previous to this investigation 4,5. The dimensions of the slabs and reinforcement are shown in
Fig. 17. The results of the tests are listed in Table 4. Since only air-cured cubes were tested
for concrete strength, the values for the water-cured cubes had to be taken from Fig. 15. In all
the tests the length of the shear plane around the studs was 285.8 mm (ll¼"in).
3.6 Comparison between haunched and plain slab push-out tests
For a given concrete strength, the maximum carrying capacities of 101.6 x 19.05 mm (4 x 3/4 in)
headed stilds were greatly reduced by being tested in haunched slabs. Although there were differ-
ences in shear surface lengths around the studs, i t can be seen from Fig. 16 that these did not
account completely for the reduction. Some of the differences between haunched and plain specimens
are set out below.
3
a) The projection of the stud heads above the bottom reinforcement was 82.6 mm (3~ in)
in plain slabs and only 33.3 tam (lS/~t) in the specimens with 50.8 mm (2 in) haunches
and non-existant in the 101.6 mm (4 in) haunches. (Fig. 17 and 4). The projection of
the studs and the spacing of the transverse bars determines the slope of the shear surfaces in front and behind the studs. The slopes of the shear surfaces in the plain
slabs were 1:1.5 and in the 50.8 mm (2 in) haunehed slabs 1:3.5. If the spacing ofthe
bottom transverse reinforcement did not exceed 3 times the projection of the heads of
the studs above the bars, a minimum slope of 1:1~ should be maintained (Fig. 19).
The slope of the shear surface achieved in a push-out specimen depends to a certain
extent on the distance of the connector from the reaction surface of the slab. This
slope would be 4:9 in both the plain and haunched slabs, ignoring the transverse rein-
forcement.
b) It was shown in Ref. 5 that the conditions at the bases of the concrete slabs in a
push-out test may influence the maximum carrying capacities of studs. In this series
of tests the reacting surface of the slabs changed in shape with each change in haunch
dimension.
c) The different pressure distribution on the reacted surface may have also decreased
the carrying capacities of the studs by increasing the compressive stresses in the
haunch.
Beams with haunched slabs are being tested at Imperial College to determine
the degree of similarity with the push-out specimens.
3.7 Proposals for the design of haunches in beams (Fig. 19).
In order to develop the full capacity of stud connectors in beams with haunches, the
following tentative proposals are made:
1) A minimum cover of 50.8 mm (2 in) is recommended to prevent bursting of the
haunch.
2) Although this series of tests did not ascertain the maximum height to width
ratio to achieve a reasonable degree of containment, a tentative ratio of 1:1~ 6 is proposed in the light of German tests on bar connectors
3) The spacing of the bottom transverse reinforcement should not be greater than
3 times the projection of the studs above that reinforcement, in order to main-
tain a shear surface slope of 1:1~.
4. CONCLUSIONS
1. The maximum carrying capacities of 101.6 x 19.05 mm (4 x ¾ in) headed studs were greatly
reduced in the haunehed - slab push-out tests, In an actual beam the shear stress in the haunch
would be limited by the C.P. 117 (Part 2) recommendations, and if bursting and pulling-out can be
prevented the full potential of connectors should be developed.
" " ." , . It
/
2. Bursting of the sides of haunches ~occurred if a concrete cover of less than 50;8 (2 in) was
provided from the sides of the 101.6 x 19.05 mm (4 x 3/4 in) headed studs.
3. Helical reinforcement around the studs prevented bursting when a horizontal concrete cover of
38.1 mm (1~ in) was provided in a 101.6 mm (4 in) deep haunch.
4. Specimens wh!c h did not fail by bursting of the haunch and pulling out and shearing of the studs,
failed by shearing and crushing of the haunch.
5. ACKNOWLEDGEMENTS
The work described in this report i s part of a programme of research of the Road, Research Laboratory,
and was carried out under the supervision of Dr. J. C. Chapman in the Engineering Structures , ~ " ¢
Laboratories of Imperial College.
6. REFERENCES
1. CHAPMAN,-J. C. 'The behaviour of composite beams in steel and concrete' Structural Eng.~
April, 1964, No. 4 Vol. 42. 2. VIEST, t. M., C . P . SIESS, J. H. APPLETON and N. M. NEWMARK~'S~udies of slab an~
beam highway bridges - part IV. Fullscale tests of channel shear connectors and compgsit[~
T-beams. 'Bulletin - 405,Univ. of Illinois, Eng. Experiment Station, 1952.
3. CP. 117: Part 2:1967 BRITISH STANDARD CODE OF PRACTICE, COMPOSITE CONSTRUC-
TION INSTRUCTURAL STEEL AND CONCRETE. Part 2. Beams for Bridges.
4. CHAPMAN, J. C. and S. BALAKRISHNAN. 'Experiments on composite beams', Structural Eng.
No. 1964 No. 11 Vol. 42. 5. TERASZKIEWICZ, J. S. 'Tests on stud shear connectors' RRL Technical Note No. 36,
December, 1965. • " ~ " " t 6. STEINHANDT, O. and K. MOHLER: 'Versuche zur Ermltthh~deu.Scherfeshlghel des Betons
'Der Bauingenieur. Zg (1964) Heft. 8.
7. APPENDIX
The concrete mix was designed for a cube strength of 41,518 x kN/m 2 (6000 lb/in 2) a t 14 days.
In addition to cubes, cylinders were east to compare with American tests on channel connectors 2.
The slab's were cast horizontally on the joist flanges. The flange surfaces were wire brushed
before casting and bond was destroyed during testing.
A poker vibrator was used to compact the concrete, especially around the connectors.
Mix by weights: '
, t 1 rapid:hardening Portland cement
5.4/Aggregate (60 per cent 19.05 mm (¾ in) gravel)
(40 per cent 4.76 mm (3/16 in) sand)
"0.57 Water /
The specimens cubes and cylinders were cured under wet hessian for a week. Half the
cubes and cyliliders were then immersed in water until they were tested; the specimen and the
remaining cubes and cylinders were cured in air for another week.
T A B L E I
Cracks in concrete slabs
Cover
mm (in)
19.0 (¾)
28.6 (It/s)
38.1 (1~)
38.1 (1~) With helical reinforce-
merit
50.8 (2)
63.5 (2~)
76.2(3)
Crack Position
At level of stud Behind stud (no
compression) In front of stud
At level of stud Behind stud (no
compression) In front of stud
At level of stud Behind stud (no
compression) In front of stud
At level'of stud Behi nd stud (no
compression) In front of stud
At level of-stud , Behind stud (no
compression) In front of stud
At level of stud Behind stud (no
compression) In front of stud
At level of stud Behind stud (no
compression In front of stud
]01.6 mm (4 in) Haunch
Load per Stud kN (T)
56 (5.6) 68 (6.8)
68 (6.8)
56 (5.6) 77 (7.7)
77 (7.7)
62 (6.2) 68 (6.8)
85 (8.5)
57 (5.7) 62 (6.2)
83 (8.3)
Slip mm (in)
50.8 mm (2 in) Haunch
Load per Stud Slip kN (T) "ram (in)
0.330 (0.013) 62 (6.2) 0.305 (0.012) 1.270 (0.050) 69 (6.9) 0.508 (0.020)
1.270 (0.050) 87 (8.7) 2.286 (0.090)
65 (6.5) 0.305 (0.012) 87 (8.7) 2.54 (0.102)
87 (8.7) 2.54 (0.100)
0.305 (0.012) 62 (6.2i' 0.457 (0.018) 1.524 (0.060) 68 (6.8) 0.660 (0.026)
1.524 (0.060) 68 (6.8) 0.660 (0.026)
0.406 (0.016) 0.508 (0.020)
1.270 (0.050)
0.250 (0.010) 75 (7.5) 0.406 (0.016) 0.356 (0.014) 87 (8.7) 1.067 (0.042)
1.270 (0.050)! 93 (9.3) 1.778 (0.070)
75 (7.5) 0.406 (0.016) 99 (9.9) 1.270 (0.050)
99 (9.9) :1.270 (0.050)
87 (8.7) 0.737 (0.029) 99 (9.9) 1.524 (0.060)
99 (9.9) 1.524(0.060)
7
TABLE 2
Concrete properties
Height mm (in)
I01.6 (4)
101.6 (4)
101.6 (4)
101.6 (4)
50.8 (2)
50.8 (2)
50.8 (2)
50.8 (2)
50.8 (2)
50.8 (2)
Specimen
H aun ch
C o v . e r
mm (in)
19.0 (~)
38.1 (1%)
38.1 (19
50.8 (2)
19.0 ( ~
28.6 (1'/~)
38.1 (1~)
50.8 (2)
63.5 (2~)
76.2 (3)
101.6 mm (4 in) cube strength
kN/m 2 (lb/in2)
Slab 1 'Slab 2
152.4 x 304.8 mm (6 x 12 in) cylinders
kN/m 2 (lb/ifi2)
Slab 1 Slab 2
Air Water Air Water Air Water Air Water
Cured
40 688 39 719 45 531 43 594 26 295 25 741 30 654 26 848 (4880) (5740) (6580) (6300)! (3800) (3720) (4430) (3880)
40 688 31 969 44 563 43 594 27 402 27 402 28 509 28 509 (5880) (4620) (6440) (6300) (3960) (3960) (4120) (4120)
40 688 38 750 44 563 43 594 29 547 26 848 25 741 27 402 (5880) (5600) (6440) (6300) (4270) (3880) (3720) (3960)
I
44 563 42 625140 688 36 813 27 402 25 741 30 654 24 080 (6440) (6160) (5880) (5320) (3960) (3720) (4430) (3480)
48 438 45 500 45 500 44 563 32 315 29 408 27 402131 761 (7000) (6720) (6720) (6440) l (4570) (4350) (3960) (4590)
49 406 45 500 54 250 47 469 31 761 28 993 33 975 28 993 (7140) (6720)i (7840) (6860) (4590) (4190) (4190) (4190)
51 344 49 406! 53 281 48 438 33 422 33975 29 547 32 868 (7420) (7140): (7700) (7000) (4830) (4910) (4270) (4750)
52 313 44 563 53281 48 438 35 567 31 208 32 315 31 208 (7560) (6440) (7700) (7000) (5140) (4510) (4670) (4510)
58 125 49 406 52 313 53 281 31 761130 654 32 868 30 100 (8400) (7140) (7560) (7700) (4590) i (4430) (4750) (4350)
52 313 49 406 55 219 51 344 !33 422 35 013 35 013 33 422 (7560) (7140) (7980) (7420) (4830) (5060) (5060) (4830)
The properties were measured after each push-out test. In consequence the age at which
the above tests were made is not constant but is usually greater than 14 days.
Specimen
Haunch
Height Cover mm ram (in) (in)
I
101.6 19.0 (4) (~)
I
101.6 38.1 (4) " (1~)
I
101.6 38.1 (4) ( I~ )
I01.6 50.8
(4) (2) I
50.8 ! 19.0 (2) (3/4)
I
50.8 28. (2) (14 )
I
50. 8 38.1 (2) (1~)
I
50.8 50.8 (2) , (2)
I
50.8 63.5 (2) (2~)
I
50.8 76.2 (2) (3)
TABLE 3 Maximum •carrying capacities of 101.6 x 19.05 mm
(4 x ~ in) headed studs in haunched slabs
Water cured Maximum carrying 101.6 mm
• capacity • (4 in) cube kN/Stud
kN/m2 (tons/stud) Uw (lb/in 2)
39 719 70.3 (5740) (7.03)
31 969 77.0 (4620) (7.70)
38 750 85.0 (5600) (8.50)
42 625 (6160)
44 563 (6440)
83.0 (8.30)
87.0 (8.70)
46 500 87.0 (6720) (8.70)
48 438 89.5 (7000) (8.95)
48 438 95.0 (7000) (9.50)
49 406 i 99.5 (7140) (9.95)
49 406 101.0 (7140) ( I0 . i 0 )
• R em arks
Haunch bursts
Haunch bursts
Studs with reinforce- ment - Haunch shears
Haunch shears
Stud shears Haunch bursts
Stud shears Haunch bursts
Haunch shears
Haunch shears
Haunch shears
Haunch shears
Ls,/E kN~
• (lb 1/2)
26.59 (398)
30.57 (459)
33.74 (505)
40.62 (608)
44.90 (672)
47.10 (705)
50.11 (750)
53.45 (800)
56.26 (842)
62.47 (935)
9
TABLE 4
Tests on 101.6 x 19.05 mm (4 x ~ in) studs in slabs without Haunches
Reference
101.6 mm (4 in) cube
Air Cured
kN/m 2 (lb/in 2)
35 636 (5150)
39 442 (5700)
38 058 (5500)
25 257 (3650)
35 982 (5200)
55 357 (8000)
Water Cured kN/m 2 (lb/in 2)
34 598 (5000)
38 058 (5500)
36 674 (5300)
24 219 (3500)
34 598 (5000)
53 281 (7700)
/
• L s ~ w ' kN~ (Ibm)
55.46 (830)
58.13 (879.).
57.13 (855).
46.44 (695)
55.46 (830)
68.82 (1030)
Maximum carrying capacity kN/stud
(tons/stud)
125 (12.5)
123 (12.3)
127 (12.7)
113 (11.3)
119 (11.9)
150 (15.0)
10
i I ~ , , ~
t l - - ~ . - ~ ,~--
Plate 1 Haunch bursting in 101.6 x 133.4 mm (4 x 5~ in) Haunch
Plate 2 Haunch shearing in 101.6 x 171.5 mm (4 x 6~,/4 in) Haunch
Note reinforcement around studs
I I
Plate 3 Reinforcement around studs
Plate 4 Haunch shearing in 101.6 x 196.9 rnm (4 x 7~ in) Haunch
12
Cover
Vidth
I
i eight
Cover increases resmstonce to burs t ing .
Height of haunch reduces degree of conta inment o,t root of s tud.
Fig. 1 HAUNCH PROPORTIONS
56 - 560
c: Z 0 v
48 " 480
40 - 400
U 0 a. 32 - 320 O U
24 - 240
U
16 160
=E E
:E 8 80
0 0
i -O- No haunch
-O- With haunch
O O
O
o
O O D
O
101.6 mm (4in) x " ' 8-06 kg/m (5.4 tb/f t) channel x 152.&ram (6in) tong
[63"5mm ( 21/2 in)
.i r--Ji ! 203-2 mm (Sin)
I 13839
I 2000
I I I 276?9 41518 55357 kN/m 2
I ' I I
4000 6000 8000 [b/ in 2
Cube s t rength
Fig. 2 EFFECT OF HAUNCH IN PUSH-OUT TESTS OF CHANNEL CONNECTORS
Ref .. Viest I.M, Siess C.P., Appteton J.B., Newmark N.M. 4 " Studies of stab and beam highway b r i d g e s - P a r t .
Univ. of I t l inois But. No.5 1952.
I '
69197
I
10 000
13
~ J
133-l, mm (51/t, in) I to 3 " |
196"9 rnm(? ~in)~
Slab I
(18"x 6iRSJ /,57.2 x 152 '/.-ram
]::==
mm mm /-in) (/.in)
" ~ Helical
/.57'2mm (18in)
J reinforce ment
Slob 2
mm mm - ~ in)=~in) -
included In 101"6 xl"/l '5mm (/.x631/. in) haunch only
228- (gin
228 (9i~
-• 95.3rr 30/.'Smm (33/h i (12in)
REINFORCEMENT CAGE PER SL/~B
~] 228-6mm __L gin)
9.Smm dio. M.,~Bors ( 3/8 in)
= ~ 76"2 mm I IC'in'
-203' 2 mm _J_(8in)
Fig. 3 PUSH-OUT SPECIMEN WITH 101'6mm (41n) HAUNCH
r .
1 5 2 " / . mm (6in)
E
r r r r J l r ~
I
Load REINFORCEMENT
CAGE PER SLAB
( 18"~ 6~ RSJ /.57.2x 152'-/. mm
,/.57"2 mm A
118i.1 f 50"8mm (2"m)
L I
228"6mm (gin)
=1• 228-6mm (gin)
r l l l r r L w r r r r
I 152"4mm
I ---•28 "6mm
9in)
9-5mm dia,M.~Bors ( 3/8 in)
T, ,mm H 'o3"2mm ' ~=~___~ (8 in)
Fig,/, PUSH-OUT SPECIMEN WITH 50-8ram (2 in) HAUNCH
14 I
10 m
O
8
qD
In
d /. 0 '
. J
O0
z
80
60
40
20!
I I _Push-out test w i thout . . - - - ~ ' ' / haunch ( ref. 4 )
Slab I and 2 on opposite f I anges of (18x 6in) R.SJ.
~ ~ l . I I .
- Cover f / S t a b 2 ~ 19"Omm 133:4m~n
1 haunch bursts ~ _ , s tudsput t out ~ •
~ ] s t i p= 12.7 mm (0.5in)
I l ." I
0 2" 54 5-08 mm 7-62
L-- I I #
0 0.10 0-20 in 0"30 St ip
F i 9 5. LOAD-SLIP FOR 101.6 x 19-05mm (4 x3//, in )HEADED STUDS IN 101.6x133./,mm (/, x 51/4in ) HAUNCH'
i n
¢3.
o
10 100
o = == /
8O I
l 6O
AO
21 20
C 0 0
I 0
F ig6
T/. / . 4 ,.) ~_~ r--U
,,n,ll I 38.1mm I / ~ ~mm
~ ( 1 . G i n ) (6-Y4in) .
J S t a b 2 Stab 1
haunch bursts . studs putt out
• s t ip = 12.?mm (0' 5 in.)
I " I I
2 .5 / . 5"08 m m 7 .62
i i , 0.10 0.20 in 0-30
S t i p
LOAD-SLiP FOR 101.6xlg.05mm ( 4 x 3,~ in ) HEADED STUDS IN 101-6xl?l-&mm
( 4 x 63/4 in ) HAUNCH
IS
0 0 .J
0 0
I0
C 0
8
I0
C 0
8
- 100 I
- 80 /
60
/ , 0
' TI In)_~_l
)01-S ?
C o v e r 38-1 mm mm (t '5 In )
N.B H e l i c a l r e i n f o r c e m e n t a r o u n d each s t u d
Slab 1 unclh shears off
I I I
0 2.5/, 5.08 mm 7-62 I, I I I 0 0"10 0"20 In 0.30
S l i p
Fig.?.. LOAD-SLIP FOR REINFORCED 101.6x19.05mm (/,x3/t, in)HEADED STUDS IN 101.6x171.Gmm (4 x63/4in) HAUNCH. ( WITH HELICAL REINFORCEMENT AROUND EACH STUD}
100
80
6O
~0
20
ol 0
I
0
/ 2"5/,
0.10
T I I :4 in) _~._L_. _..J
f l I :4 I n ) j | I .
Cover ~ 50-8mm ..~...) ~b-~ mm (2in) ¢/')/41nJ
Stab I " ~ . ~ ~ u n c h shears off
I S t a b 2
I I
5.08 mm 7.62
I I
0-20 in 0 30 S t i p
Fig.8. LOAD-SLIP FOR 101-6x19-05mm (/, x 3//, in ) HEADED STUDS IN 101-6x196.9rnm ( L, x 7 3//' in ) HAUNCH
16
10
t - O .0-,,
8
'10
. . . . . . _.=_ 6 ~ in
-¢3
o ...l
I00 I / ~ z I ' S lab 2
80
/ ~ r f / Slab I I r ' ~ ' load drops suddenly.. I . ~ / when stu_d shears off
~ n L ~ . . . . . . . . . . . st i =12 ?mm . . . . . . . =
I ,05 !~'a, II I Y , ,
C o v e r 133~.4rnm - 2 0 ~ | ~ O m m (3/4 in ) (5114in)
"lO = 6 (/I
'10 cs /, O
._J
0 ' O
I 0
I I I
2-5& 5-08 mm ?.62
I I I 0.10 0.20 in 0.30
St ip
' F!g.9. LOAD-SLIP FOR 101.6x 19-05mm ( / .x3 / / , in ) HEADED STUDS IN 50-8x133"/,mm • (2 x 51//. in )HAUNCH
10 100 c z I
° : o L / 8
60
/,0
20
[6 in ) 5(>8 m m
Cover 2 8 . 6 mm (11/8 m ) (6 in )
• S t ab ~ ' ~ load drops suddenly when stud shears off s l i p = 12.?ram
( 0.5 in.)
=.~ Stab 2
0 I I I 0 2.5/. 5-08 mm ?-62
I I I i
0 0-10 0.20. i n 0-30 S l i p
Fig. 10 LOAD-SLIP FOR 101-6 x 19.05mm (/, x 3//, i'n ) HEADED STUDS IN 50.8x152./. mm
( 2 x 6 i n ) HAUNCH
1 7
10 ¢.-
0
"10
3 6 I / I
a .
" o o l , 0
. . J
lOO r I
6 0 -
In~ , . . toad drops when I~ 15~t. T J J large cracks appear
,n IF ..~P. I I I , suddenly above studs " ~ ~ ' ~ ' I I I (~ st ip=12.7 mm
II ~ ~-'~ I " 1 ,o.,,n,
01 l I I 0 2.5& 5.08 mm ?.62
I I I I
0 O. I0 0.20 i n 0.30 S l i p
Fig.11. LOAD-SLIP FOR 101-6 x 19-05 mm (& x 3 t in ) HEADED STUDS IN 50"8 x171.Smm (2 x 63//, in) HAUNCH
10 t - O
10
,,?,= 6
0 .
" 0 o l, 0
. J
100 e
z r : ~~ o-~ ~..,~ :J 60 ~ im-~4 m
TI I ~o=. <"°'1/ /
~,, L , 5~Smm 1969 mm ,Lu F ~ "('2 in) (?3/4 in )
haunch shears off stl p=12.?mm
[0-5 in.}
/ S L a b 2
O I I I I
0 2.5/, 5.08 mm 7.62
I I I I 0 i 0.10 0.20 in 0"30
S l i p
Fig.12. LOAD-SLIP FOR 101.6x19.05mm (4x3//, in)HEADED STUDS IN 50.8x196"9mm ( 2 x 7 3/4 in ) HAUNCH
18
10
o
8
O .
O .--I
10 ¢/I t - O
8
"10
6
OJ
10 ¢J /, O
,--I
- 1 0 0
8O
60
{*0 [6in) ~ I Increasing sl ip
5O8 ~ mm ~.,,,11
I _ _1 Cover r 222.3 mm-7
20 63-5mm (2V21nJ (83/4 in)
0 I I I 0 2.5/, 5.08 mm 7 " 6 2
I I I I
0 0.10 0.20 i n . S l i p
Fig.13. LOAD-SLIP FOR 101.6 x19-05mm ( / , x 3 # , i n ) H E A D E D STUDS IN ( 2 x 8 3//, in) HAUNCH.
0.30
50"8 x 222.3mm
100
Z v
80
60
~0
20 ~
2
1 :6i. I L
Cover ~ -, 76.2mm 2/,7 7 mm (3in) (9 3/4 in)
/ S tab 1 load decreases graduat ty w i th I'ncreasmg sl ip
0 L 0 2.5~; 5.08 mm 7'62
I I I 0 0"10 0.20 in 0"30
S l i p
Fig. 1/,. LOAD-SLIP FOR 101.6 x19-05mm (/, x 3//, in ) HEADED STUDS IN 50.8x2/,?,7 mm
( 2 x 93#,1n) HAUNCH
19
e-
L .
" 0 ¢D
.L. <C
I0 0 0 0
5000
69197
z J¢
3~598
0 0
F 0
I 34598
, -0 -
--(3-
kN/m l 69197
10t6mm (4 in) Cube 152./,mm dia. (6in) Cy|inder 30&.8mm (12 in) tong
I I I 0 5000 tb/in l 10000
Water cured strength
Fig. 15. CONCRETE PROPERTIES IN SLABS
7.0
15 -
-o = 3 r "
O .
.~_ 10 U 0 O. 0 U
a t C
am > , , i,.. t , .
O
E 5 E
.w X O
150
Z v
100
50
0
,p /
/
~---- -~:u~c~:2 ,~ou,
/ ~__.._-.-~Stobs w i th haunches Reinforcement / , ~ - - -
~ , ~ -(3- 101"6mm (4in) deep haunch ~ , ~ 50-8mm(2in)dee p haunch
u ,-13- No haunch
.Shear prone I ~ ~ m (in) I ~ - - ¢ ~ . f / l Uw= Water cured L-~"I] 1 1 ~ cube strength I i l 11 1 " kN.Imm 2 ( tbl in 2)
0
I
!
33'&1
I
0 500
LsdUw- - , -
66"82 k N
I
1000 Lb
Fig.16 LOAD- SHEAR PLANE FOR 101.6x19-05mm ( & x 4 3 ~ i n ) HEADED STUDS
30/.'8mm _, 1_228-6mr~j 228.6mm_J r,,,,o, ,,,o, r,,,o) i
• 1 ,2.7m~.
Ji"n) L ~ " - - (5116 i n } di o.
63.5mm_ J ~ " ~ ' ~ t2 • ?mm ( 2bin ) . . . . (I/2 in ) dio.
F ig. l? SLABS WITHOUT HAUNCHES.
21
" O
n
¢-
0 U
E
E X
IE
50
(¢) ¢-
10
150
100
50
Fig. 18
PU,= 0 " 1 7 1 ~
/ /
/ /
/ /
/
I I
I
/
0 S / .
/ /
0
S
0 @• 0
0
0
~ D
1
101.6mm -O- (4 in) Deep haunch
508 mm - l - (2 in) Deep haunch
-D- No haunch
0 I I I I I I I 0 6919 13839 2 0 ? 5 9 2 ? 6 ? 9 34598 /,1518 48438_ kN/m 2
I I I I I I I I
0 1000 2000 3000 4000 5000 6000 7000 tb/in z Cube s t rength
EFFECT OF HAUNCH IN PUSH-OUT TESTS ON 101.6x19,05mm(4x3/4in)
HEADED S]:UDS
22
=i° S0~8=n,I I L IS0.mm ,2., ! !L,,., 11/2 h _ .
!
Min. 50-8 mm (2 in )
i'i/ 11/2 h
50.Smm (2in)
Fig.19 PROPOSALS FOR DESIGN OF HAUNCHES
23
• k
Printed at the Road Besearch Laboratory, Crowth'orne, Berkshire, England.
i ;
l i l t
= I i
.-
,e_
m t
=
m
g
-
ABSTRACT Static tests on stud shear connectors in haunched slabs: J .S . Teraszkiewicz: Ministry of Transport, RRL Report LR 223: Cmwthorne, 1968 (Road Research Laboratory). Push -ou t tests were carried out on ten haunched slabs at Imperial College with 101.6 x 19.05 mm (4 x ~ in) headed studs. Four tests were made on specimens with 101.6 mm (4 in) deep haunches and concrete cover to studs varying from 19.05 - 50.8 mm (~ - 2 in). Another six t e s t s were made on spec imens with 50.8 mm (2 in) deep haunches, and horizontal concrete cover to •studs varying from 19.05 x 76.2 mm (~ - 3 in).
Bursting of the haunch occurred in the spec imens with a cover of less than 50.8 mm (2 in). When helical reinforcement was provided around the s tuds in a specimen with a 38.1 mm (1~ in) cover, no bursting occurred. Haunch crushing and shear- ing occurred in all the specimens which did not burst.
The maximum carrying capac i t i es of the s tuds v a r i e d from 70 - 101 kN ( 7 . 0 - 10.1 tons). (The capac i ty of s tuds tes ted in s labs without haunches is about 135 kN (13~ tons). On the bas i s of the tes ts proposals are made for design.
m m :
m
| • • • • • • • • • n • • • • • • • • n • • • • • • • • • • • • • • • • • • | • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • I l l l l i I l l
i ; m" i
i _- ABSTRACT -" Static tests on stud shear connectors in haunched slabs: J .S . i i
• Teraszkiewicz: Ministry of Transport, RRL Report LR 223: ;. Crowthorne, 1.968 (Road Re'search Laboratory). Push-out tes ts " were carried out on ten haunched s labs at Imperial College with .; 101.6 x 19.05 mm (4 x g in) headed studs. Four t e s t s were -" made on specimens with 101.6 mm (4 in) deep haunches and = concrete cover to studs varying from 19.05 - 50.8 mm (?4 - 2 in). = \no ther six tes ts were made on specimens with 50.8 mm (2 in) ; deep haunches, and horizontal concrete cover to s tuds varying g" from 19.05 x 76.2 mm (~4 - 3 in). m
= Bursting of the haunch occurred in the spec imens with a ; cover of less than 50.8 mm (2 in). When helical reinforcement ~r w a s provided around the studs in a specimen with a 38.1 mm - ( l " " . . . . • in) cover, no bursting occurred. Haunchcrush ingand shear- =' ing occurred in all tile specimens which did not burst.
= Tile maximum carrying capaci t ies of tile s tuds varied = from 70 - 101 kN (7.0 - 10.1 tons). (The capaci ty of s tuds = tested in s labs without haunches is about 135 kN (13~4 tons). = On the basis of ti~e tes ts proposals are made for design. =
t
