An Experimental Study of Welded Bar Sleeve Wall Panel Connection under Tensile, Shear, and Flexural Loads
International Journal of Concrete Structures and Materials
An Experimental Study of Welded Bar Sleeve Wall Panel Connection under Tensile, Shear, and Flexural Loads
Jen Hua Ling
Ahmad Baharuddin Abd. Rahman
Izni Syahrizal Ibrahim
Zuhairi Abdul Hamid
Rs Rsv Ry
This paper presents an experimental study of a new grouted splice connection for wall panels, called Welded Bar Sleeve (WBS). The connections were made from steel pipes and tested with incremental tensile, shear and flexural loads until failure. The aim is to determine the behaviour of the connection under the three load cases. For this, the connections are evaluated in terms of the load-displacement responses, ultimate capacities, ductility responses and some feasibility assessment criteria. WBS was found to provide sufficient strength at the bar embedded length of 8, 8 and 11 times the bar diameter under tensile, shear and flexural loads, respectively. It is effective under tension, but could only service up to 1/3 of its ultimate shear capacity. Flexural load is the most critical load case for the connection. For this, further enhancements are required when subjected to shear and flexural loads.
grouted splice sleeve; precast wall connection; tensile; shear and flexural loads; confinement effect; feasibility study
List of Symbols
db Diameter of bar embedded in the sleeve, mm
dse Outer diameter of sleeve, mm
dsi Inner diameter of sleeve, mm
dwb Diameter of bar welded to WBS, mm
fsy Nominal yield stress of spliced bar, N/mm2
fu,b Ultimate tensile stress of bar, N/mm2
fu,c Ultimate compressive stress of concrete, N/mm2
fu,g Ultimate compressive stress of grout, N/mm2
fu,m Ultimate compressive stress of mortar, N/mm2
H Height of the upper panel, mm
lb Bar embedded length in sleeve, mm
lsl Length of sleeve, mm
tsl Thickness of sleeve, mm
Psv Service load of specimen, kN
Pu Ultimate capacity of specimen, kN
Pu,ft Ultimate capacity of wall assembly specimen under
flexural load, kN
Pu,st Ultimate capacity of wall assembly specimen under
shear load, kN
Ultimate capacity of grouted splice specimen under
tensile load, kN
Yield strength of specimen, kN
Displacement at failure, mm
Drift of upper wall panel at failure under flexural
Horizontal displacement of bar 1 at failure under
shear load, mm
Horizontal displacement of bar 2 at failure under
shear load, mm
Displacement of bar at failure under tensile load,
Displacement at yield, mm
Grouted splice sleeve is a mechanical coupler used to
connect steel bars. A typical grouted splice consists of two
steel bars, a sleeve and some grout (Fig. 1). The steel bars
are bonded with non-shrink and high strength grout in the
sleeve. The sleeve acts as a confinement body to resist the
lateral expansion of the grout and control the propagation of
the splitting cracks surrounding the bar (Fig. 2), and thus,
enhances the bond between the bar and the grout. In
addition, the sleeve bridges the discontinuity of the spliced
bars so that stress can be effectively transferred from one bar
This technique of confining the bond region was an
extreme condition of the regional confinement using the
transverse reinforcements. It allows the stresses to be fully
transferred at a shorter anchorage length of the bars as
compared with the conventional bar lapping system. The
required length ranges from 8.5 to 16 times the bar diameter
(Haber et al. 2015)
The grouted splice sleeve can be used as the connection
for precast concrete structures. It is embedded in the precast
concrete elements during fabrications in the factories. At the
construction site, steel bars extruding from the other precast
element are inserted into the sleeve to form a connection
(Fig. 3). Due to the enhanced bond performance, the
extruding bars from the precast elements are kept minimal.
Thus, the handling and installation of the elements are easier
and this speeds up the construction project.
Grouted splice sleeves have been the proprietary products
(Haber et al. 2015; Jansson 2008; Lin and Wu 2016)
by several international companies. Designing the sleeves
have been the works of specialists. In 1995, Einea et al.
(Einea et al. 1995)
proposed to connect steel bars with
modified steel pipes. Researchers then realised that with
adequate understanding of the load resisting mechanism, the
materials that are commonly available at the construction site
could easily be transformed into the grouted splice sleeves.
Since then, various materials and shapes have been
proposed as the connection for steel bars. This includes mild
(Henin and Morcous 2015; Abd. Rahman et al.
2010; Ling et al. 2012; Alias et al. 2014; Alias et al. 2013)
high strength steel
(Seo et al. 2016)
, aluminum tubes
et al. 2008; Tullini and Minghini 2016)
Hosseini and Abd. Rahman 2013; Aldin Hosseini and Abd.
Rahman 2016; Aldin Hosseini et al. 2015; Sayadi et al.
2014; Hosseini and Rahman 2013)
, square hollow sections
(Ling et al. 2014) and glass fiber reinforced polymers
(Sayadi et al. 2015; Koushfar et al. 2014; Tastani 2002;
Tibbetts et al. 2009)
These connections differ from one another in terms of
(a) the mechanical properties of materials used and (b) the
load resisting mechanisms as a result of the sleeve
configurations and designs. Therefore, the response of connection
Upper wall panel
Lower wall panel
Extruding reinforcement bars from the upper panel
Grouted splice sleeve used to receive the insertion of the bars from the upper panel.
Reinforcement bars of the lower panel
under load, the required anchorage length of the bars and the
amount of materials required vary slightly among each other.
Nevertheless, these connections have the following in
a. The sleeve needs to resist the tensile load and confine
the bond at the same time. Both the longitudinal and
lateral deformations are detected under tensile load.
b. The mechanical interlocking among the grout, the
spliced bar and the sleeve are equally important. The
bond slip failure could occur at the bar or at the sleeve.
These connections might not be as effective as the
proprietary products in terms of having a minimum anchorage
length, but they are advantageous in the following aspects:
a. The materials used are easily accessible on any
b. The connection can be fabricated on site by using
simple techniques such as welding and cutting.
c. The connection can be modified to suit the needs on site,
such as the allowable tolerance and anchorage length.
Grouted splice sleeves are usually tested with a tensile
load to determine the feasibility and the characteristic
strength. The test is simple, cheap and easy to handle. The
relevant standards specify a minimum tensile capacity of
125% of the nominal yield strength of the spliced bars
(ACI318 2002; AC-133 2008)
. A good grouted splice connection
generally offers a stiffness about equivalent to a steel bar and
undergoes the stages of elastic, yielding and plastic
responses when subjected to incremental tensile load (Ling
et al. 2012). The design capacity is recommended to be not
higher than the yielding strength.
However, the tensile test alone is insufficient to determine
the actual behaviour and performance of the grouted splice
connection in precast concrete structures. The loads acting
on the connection might not always be in tension. There
could be other forces acting on the connection. Hence,
experimental studies were conducted on the precast concrete
frames with the connections of beam-to-beam
Hosseini et al. 2015; Sayadi et al. 2014)
(Ameli et al. 2015; Kim 2000)
and Minghini 2016)
(Soudki et al. 1995; Zhu
and Guo 2016)
(Haber et al.
2014; Belleri and Riva 2012)
to determine the structural
This study transforms steel pipe sections into grouted
splice sleeves by simply welding some steel bars on it. These
sleeves are used to connect the precast concrete walls
(Fig. 3). It is to determine if these non-proprietary sleeves
can be used as the connection for walls.
Depending on the locations installed, the connections are
subjected to tensile, shear and flexural loads when the wall
frame system is subjected to lateral load (Fig. 4). To
determine the behaviour and the feasibility of the connections, an
experimental study was conducted. The aim was to acquire
the responses of the connection under different load cases.
2. Experimental Program
2.1 Test Specimens
Welded Bar Sleeve (WBS) was made from mild steel pipes
(nominal yield strength, fsy = 250 N/mm2) with the inner
diameters, dsi, of 50, 65 and 75 mm. Four steel bars
(fsy = 500 N/mm2 and dwb = 10 mm) were welded to the
inner surface of the pipe at the ends (Fig. 5). These bars
provide an interlocking mechanism for the grout to bond
with spliced bars. Then, steel bars (fsy = 500 N/mm2 and
bar diameter, db, of 16 mm) were spliced at the embedded
lengths, lb, of 75, 125 and 175 mm (Fig. 5; Table 1).
Non-shrink grout (Sika Grout-215), with a nominal
strength of 70 N/mm2 at day 28, was mixed into a pour-able
state based on the proportions recommended by the
manufacturer (4 litres of water: 25 kg of grout). The grout was
poured into the sleeve prior to insertion of the steel bar.
2.2 Test Programs
2.2.1 Tensile Test
Nine sets of specimens with different configurations were
tested with 0.5 kN/s incremental tensile load (Table 1). Each
set consists of three identical specimens; thus, a total of 27
specimens were tested with the tensile load (Table 2).
The displacements were measured by using the built-in
linear variable differential transducers (LVDT) of the
hydraulic actuator (Fig. 6). Three strain gauges (SG) were
installed on each specimen (Fig. 6);
i. SG1 was installed on the spliced bar at about one bar
diameter from the surface of the grout. It was used to
measure the elongation of the bar
ii. SG2 was installed transversely on the sleeve at the mid
length of the bar embedded length. It was used to
measure the lateral deformations of the sleeve due to
splitting expansion of the grout in the sleeve
et al. 1995; Henin and Morcous 2015)
iii. SG3 was installed longitudinally at the mid length of
the sleeve. It was used to measure the longitudinal
elongation of the sleeve.
2.2.2 Shear and Flexural Tests
For the shear and flexural tests, six specimens were tested
each. This included a control and five wall assembly
specimens (Table 2).
Each specimen comprised two precast concrete panels as
illustrated in Fig. 7. The dimensions of the panels are given
in Table 3. Two sleeves were embedded in the lower panel
and two steel bars are extruded from the upper panel. During
installation, the steel bars were inserted into the sleeve and
bonded by the grout in the sleeve. A layer of 25 mm mortar
dry pack was laid between the two panels.
For the control specimens, the reinforcement bars were
continuous and embedded in the wall panels with a full
anchorage length. The dimensions were same as the other
specimens, as specified in Table 3.
The displacement of the panels was measured by a series
of LVDTs illustrated in Fig. 7, H1 to H10. Strain gauges were
installed along Bar 1 of each specimen. Strain gauges SG1 to
SG3 were installed at the same positions as the tensile test.
SG4 and SG5 were installed on the spliced bars at a distance
of 200 mm intervals.
The incremental lateral load was imposed by the hydraulic
jack (Brand: Enerpac, Capacity: 500 kN) at the dry pack
joint and at 1800 mm height from the joint for shear and
flexural tests, respectively. The experiment started with a
load-controlled mode where readings were taken at every 10
kN load increment. Then, as the specimen yielded and a
large displacement was detected, the
displacement-controlled mode was used. Readings were taken at every 2 mm
displacement. This was in order to obtain a smooth load–
While conducting the experiment, the yielding of the
specimen was detected when the real-time
load–displacement response was no longer linear, and a large displacement
was detected with respect to a small load increment.
The tests were conducted as per the standard procedures
recommended by ASTM E564 (E564-06 2006). Prior to
commencement of the test, all instrumentation readings were
initiated to zero. A preload of about 10% of the estimated
ultimate load was applied and held for 5 min to seat all the
connections. The pre-load was removed for another 5 min
before all the gauge readings were read as the initial
The incremental load was applied in three cycles at 10 kN
load interval. The load was maintained for at least 1 min
before each reading was taken. As the load achieved 1/3 and
2/3 of the estimated ultimate load (which are 100 and 200
kN for shear load, and 20 and 40 kN for flexural load) the
applied load was released at the same rate. As the load was
fully removed, the recovery of the specimen was recorded
after 5 min. The connection was tested to fail in the third
3. Results and Analysis
3.1 Load Capacities
Table 4 shows the compressive strengths of the grout,
concrete and mortar dry pack on the day that the specimens
were tested. The ultimate capacity, displacement and failure
mode of each specimen are shown in Table 5.
The specimens generally failed in two modes, namely bar
fracture and bond-slip failures. The bar fracture failure is
preferred as it indicates that the grouted splice could
generate a higher bond strength than the tensile strength of the
spliced bars. Based on the results, the spliced bars generally
fractured at about 128, 297 and 82 kN for tensile, shear and
flexural loads, respectively.
For this, the specimens offering a higher capacity than
these values are considered to be adequate. The adequate
specimens are: (a) WBS-4, 5, 7, 8 and 9 for tensile test;
(b) WBS-5, 6 and 8 for shear test, and (c) WBS-5 and 8 for
For this, the following is found (Table 5):
a. The embedded length of 125 mm (&8db) is adequate
for resisting tensile load.
b. The embedded length of 125 mm (&8db) is adequate
for WBS to withstand shear load, regardless of the
sleeve diameter. As the bar embedded length required to
resist the shear load could be shorter than 125 mm, and
with the amount of data available, it is difficult to
determine if the sleeve diameter affects the shear
capacity of the connection.
c. To resist flexural load, 175 mm (&11db) bar embedded
length is required.
Based on these findings, the followings can be concluded:
a. The loading capacity of the grouted splice connection
increases as the bar embedded length increases in all
Theoretically, small sleeve diameter is beneficial to the
capacity of the connection. This can be observed from the
test results obtained from tensile test and the previous
studies. A smaller sleeve diameter offers a more effective
confinement to improve the bond performance in the sleeve
(Ling et al. 2012)
. However, it is noted that a smaller sleeve
diameter might lead to the following problems:
a. Inadequate tolerance for installation of the grouted
splice connection during erection of the precast wall
panels. As a result, the dimension of the precast panels
and the position of the steel bars and the sleeve need to
be fabricated at a higher level of precision. The
recommended tolerance is about 25 mm as stated in
b. Inadequate opening size for the filling of the grout in
the sleeve. This is reflected by the poor capacity
offered by specimen WBS-4 tested under shear and
flexural loads. For this, much effort is required to
ensure the spliced bars are fully anchored in the sleeve.
3.2 Behaviour of Grouted Splice Connection
3.2.1 Response Under Tensile Load
Tensile load caused the entire grouted splice specimens to
deform and elongate longitudinally. The deformation of the
sleeve was insignificant compared with the spliced bars. A
large deformation of the connection was noticed as the
Compressive strength of concrete, mortar and grout for each specimen (unit: N/mm2).
spliced bars yielded. The specimens eventually failed either
by bar fracture or bond-slip failures.
Two types of load–displacement responses were observed
(Fig. 8). The connections with adequate bond strength
exhibited ductility characteristics prior to failure (Fig. 8a),
while inadequate bond strength endured a brittle failure
Specimens WBS-4, 5, 7, 8 and 9 behaved elastically with
a high degree of stiffness at the initial stage, as demonstrated
by the steep gradient of the load–displacement curve in
Fig. 8a (line A–B). The sleeve and the spliced bars
elongated slowly and proportional to the load increments. As the
bars yielded at approximately 110 kN load, they elongated
rapidly and behaved plastically. As a result, the stiffness of
the connection decreased drastically. These specimens
reached the ultimate states at about 130 kN with a large
displacement of about 30 mm.
Figure 8b shows the response of the grouted splice
connection when inadequate bond strength was generated in the
sleeve (WBS-1, 2, 3 and 6). These connections generally
failed with bars slipping out of the sleeves at a low ductility.
They behaved elastically with a high degree of stiffness until
the bond between the bar and the grout failed suddenly at a
load less than 110 kN.
3.2.2 Response Under Shear Load
The shear load caused the upper panel to displace
horizontally and slide on the dry pack. The lower panel remained
stationary while the bar deformed significantly and failed by
bar fracture or bond-slip failure. Cracks were found to occur
at the cold joints between the dry pack and the panels.
Figure 9 shows a typical load–displacement response of
the wall assembly specimens when subjected to an
incremental shear load. It underwent the stages of (a) pre-crack,
(b) bar dowel action, (c) post dowel action and (d) ultimate
The pre-crack stage was a state without any crack on the
wall specimen (curve A–B). The specimen resisted the
incremental shear load with good integrity. The upper panel
displaced slowly and a high degree of stiffness was
developed with respect to the load increment.
The first crack occurred at the dry pack joint at about 100
kN. The steel bars joining the two panels started undergoing
the bar dowel action. This occurred in two stages, namely
bar bending and kinking actions
(West et al. 1993; Soudki
During the bar bending action, both Bars 1 and 2 hinged at
two points near the joints between the dry pack and the wall
panels (Fig. 10). The upper wall panel displaced horizontally
in a rapid manner due to low shear resistance generated
during the bar hinging process (curve B–C in Fig. 9). Thus,
a low degree of stiffness was developed.
The incremental shear load was applied in three cycles. A
negligible permanent displacement was detected after the
first load cycle before the bar dowel action took place. After
the second load cycle, a large permanent displacement was
detected (Fig. 11a). The deformation was due to the bar
bending and kinking actions, and it was permanent and
The results show a good continuity of load–displacement
response between the load cycles (Fig. 11b). The
load–displacement response followed the path of the previous load
cycle and continued thereafter.
All specimens failed when Bar 1 fractured except WBS-2.
These two specimens failed as the bar slipped out of the
sleeve during the bar dowel action.
The responses of both Bars 1 and 2 were similar (Fig. 11).
Bar 1 was located closer to the shear load. It generally gave
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e p ia (
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s s is
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(a) Ductile response (specimen WBS -5)
0 10 20 30
(b) Brittle response (specimen WBS -2)
Fig. 9 Load-displacement response of wall assembly under
shear load (specimen WBS-8).
Lower panel Tensile stress in bar
Bar hinged at point A and B
Fig. 10 The deformation of the bars after bar dowel action
not more than 1 mm larger displacement compared with Bar
2. This explains why the specimens always failed at Bar 1.
3.2.3 Response Under Flexural Load
The lateral load applied at 1800 mm height from the dry
pack caused a rotational movement of the upper panel. Bar 1
was in tension while Bar 2 was in compression. The upper
panel rotated and drifted until Bar 1 fractured or slipped out
of the sleeve.
Figure 12 demonstrates two typical load-drift responses of
the specimens when subjected to an incremental flexural
load. When the bond strength was adequate, the specimens
exhibited a ductile behaviour prior to failure (Fig. 12a).
Otherwise, the specimens failed in a brittle manner
Specimens WBS-2, 4, 6 failed at 19.9, 65.8 and 28.4 kN
flexural load, respectively, and gave a low ductility response.
These specimens initiated with a high degree of stiffness, but
failed suddenly as Bar 1 slipped out of the sleeve. This was
due to inadequate bar embedded length and insufficient bond
strength generated in the sleeves.
Specimens WBS-5 and 8 offered the load capacity of 82
and 87 kN, respectively. These specimens demonstrated
ductile responses where the upper panels drifted for at least
22 mm before failure.
The yield strength of the spliced bars was not achieved
during the first two load cycles. The upper panel managed to
recover to its original position with a minor permanent drift
of less than 3 mm. As the load exceeded the yield strength of
about 60 kN load, drift developed rapidly and the stiffness
It was noticed that most of the specimens experienced an
initial drift of 2–3 mm immediately after the flexural load
was applied, as demonstrated in Fig. 12b. The cause of this
phenomenon is uncertain. This could be due to the sudden
settlement of the connection as the dry pack around Bar 2
was undergoing the compressive deformation (Fig. 13).
3.2.4 Response of Internal Stresses under Different Load Cases
Figure 14 illustrates the internal stresses generated in
WBS under tensile, shear and flexural loads. The ribs on the
spliced bars and the welded bars interlock with the grout in
the sleeve. This generates a resultant stress acting
perpendicularly to the surface of the rib. The resultant stress can be
derived into two components, namely the normal and
(Abd. Rahman et al. 2010)
The longitudinal stress acting on the spliced bar prevents it
from slipping out of the sleeve. However, the normal stress
generates splitting cracks surrounding it, and this may degrade
the bond performance between the grout and the spliced bar.
As for the welded bar, the longitudinal stress prevents the
grout from slipping out of the sleeve, while the normal stress
generates confinement stress to control the propagation of the
splitting cracks. The transverse tensile stress in the sleeve also
provides confinement to the grout and controls the
propagation of splitting cracks. These confinement stresses are
beneficial in maintaining good bond performance in the sleeve.
The internal stress in WBS is believed to vary slightly with
different load cases (Table 6; Fig. 14). The magnitude of the
normal and confinement stresses should be same in all
directions when WBS is subjected to tensile load. Under
shear load, a higher stress concentrates on the region that is
in contact with it. As the componential shear load is less
dominant in flexural load, the difference between the
maximum and minimum stresses in the sleeve is less significant
than when subjected to the shear load (Fig. 14).
Low ultimate capacity
Displacement at failure
δx,b1 = H1-H2
Contribution of compressive deformation of dry pack
to the rotation of the upper panel.
4. Feasibility Evaluation of Grouted Splice
The feasibility of the grouted splice connections for each
load case is evaluated in terms of ultimate capacities,
displacement, serviceability and failure mode. The ultimate
Tensile force by
capacity represents the ability of the connection to resist
load; the displacement represents the ductility response; the
serviceability indicates the usable capacity out of the total
capacity available for the design purpose, and the failure
modes imply the causes of failure.
The assessment criteria for determining the feasibility of
the connection are:
a. C1: Tensile capacity of at least 125% of the specified
yield strength of the spliced bars
Rs ¼ fsy
Hence, the strength ratio, Rs, should be at least 1.25 (Eq. 1).
Rs is computed by dividing the ultimate bar stress, fu,b, with
its specified yield strength, fsy (Eq. 1). It indicates the degree
of additional strength generated by the grouted splice
relative to the design strength of the connection.
b. C2: The connection fails in a ductile manner for survival
(ACI-318 2002; BS8110-1:1997 1997)
The relevant indicators include the yield, ductility and drift
Comparison of the response of WBS under different load case.
The yield ratio, Ry, determines whether the spliced bars
yielded during the experiment. It is computed by
dividing the ultimate strength of the specimen, Pu, with
the nominal yield strength of the bar, Psy (Eq. 2). Ry
should be at least 1.0
(Ling et al. 2012)
Rs ¼ Psy
The ductility ratio, Rd, is obtained by dividing the
ultimate displacement, du, with the displacement at
yield, dy (Eq. 3). It demonstrates the degree of
deformation underwent by the specimens before
failure. Rd should be at least 4.0 for a low-moderate
Rd ¼ dy
The drift ratio, Rdf, indicates the degree of rotational
displacement as a result of lateral load. It represents
the horizontal displacement of the upper panel, du,ft,
with respect to the height where the lateral load was
applied, H (Eq. 4). Rdf should be at least 0.5%
(Hawkins and Ghosh 2004)
C3: The bond strength generated in the sleeve should
preferably be at least the capacity of the spliced bars.
For this, bar fracture failure is preferred.
Feasibility evaluation of the grouted splice connection in accordance to assessment criteria, with respect to each load
C1 C2 C2
Strength ratio, Rs Drift ratio, Rdf Ductility ratio, Rd Failure mode
(1) (4) (3)
a S—bar bond-slip failure, F—bar fracture failure.
b The displacement at yield is obtained from the load–displacement response of the specimens.
c The ductility ratio is computed by dividing the ultimate displacement with the average value of the displacement at yield of all specimens.
d H—the capacity of the specimen is equal or larger than the control specimen, X—the capacity is less than the control specimen.
e A—applicable, NA—non-applicable.
f The italized values or conditions not fulfilling the requirements.
d. C4: The capacity of the test specimen is equal to or
higher than the control specimen.
Thus, the shear and flexural capacities of the specimen
should be at least 302.6 and 72.5 kN respectively.
e. C5: The service load should be not be too low with
respect to the ultimate capacity.
Therefore, the serviceability ratio, Rsv, should be at least
0.75 (Eq. 5). Rsv shows the efficiency of the grouted splice
connection to resist load. It represents the amount of
capacity that is usable, Psv, out of the ultimate capacity, Pu.
Each grouted splice connection was evaluated based on
the stated assessment criteria (C1 to C5) with respect to each
load case, as summarized in Table 7. The specimens are
considered not feasible when more than one criteria are not
fulfilling the requirement. The specimens which are
considered feasible include: WBS-4 to 9 for tensile load; none
for shear load, and; WBS-5, 8 for flexural load.
Rsv ¼ Pu
Comparison of the effective bond areas under
tensile and flexural loads
The grouted splice connections are not practical for
resisting shear load as the usable capacity was too low,
which was about 1/3 of the ultimate capacity. Although the
connection was able to withstand a high shear strength of
about 300 kN, the bar dower action caused the connection to
lose elasticity at about 100 kN. Unless it is integrated with
another mechanism that is more effective in resisting shear
load, such as shear keys at the dry pack joint
(Rizkalla et al.
, the connection can only be designed at 1/3 of its
The flexural load can be derived into the componential
tensile and shear forces. The componential tensile load is
predominant due to the slenderness of the wall panel.
Flexural load seems to be more critical than the other load
cases as (a) a longer bar embedded length is required, and
(b) most of the specimens enduring bar fracture failure under
the other load cases ended up with the bar bond-slip failure
under flexural load.
This phenomenon could be due to the decrease of the
effective bond region as a result of the redistribution of the
normal and confinement stresses described in Fig. 14 and
Table 6. The componential shear force of the flexural load
pushed the spliced bar towards the sleeve wall as it was
being pulled out by the componential tensile load. Only
some areas were involved in resisting the pullout force, as
shown in Fig. 15. For that, fewer grout keys contributed to
the bond strength, and the connection failed earlier than
when subjected to pure tensile load.
Through the feasibility assessment, the following is found:
a. Grouted splice connection is effective in resisting tensile
load. The bar embedded length of 125 mm (8db) would
be applicable regardless of the size of the sleeve as long
as the sleeve diameter does not exceed 75 mm (5db).
b. The connection is not as effective when subjected to
shear and flexural loads compared with tensile load. To
resist flexural load, a longer bar embedded length of
175 mm (11db) is required. It is not recommended to
resist shear load without any shear keys at the dry pack
Based on the response of Welded Bar Sleeve (WBS) under
tensile, shear and flexural loads, it is good at resisting the
longitudinal load, but not as effective in resisting the lateral
load. For that, a longer bar embedded length is required to
resist flexural load, and it is not recommended for resisting
shear load due to unpractically low serviceability.
This study reveals that a connection found feasible under
tensile load may not necessarily be feasible under shear and
flexural loads. This raises an important question whether the
tensile test can be a rule of thumb to determine the feasibility
of a grouted splice sleeve as a connection for precast
concrete structure, noting that it may be subjected to various
kinds of load. To-date, the industry is still very much relying
on it as the main assessment criteria to determine the
feasibility of a grouted splice connection.
We believe that the stress distribution in WBS varies
slightly with respect to different load cases. It may be
conceptually logical, but the internal response illustrated in this
paper is still hypothetical. Finite element analysis may be
required to validate that.
It would be a significant breakthrough if a reliable
correlation among tensile, shear and flexural loads could be
established through empirical, analytical or numerical
methods. By then, tensile test can be used to determine the
behaviour and feasibility of the connection under shear and
flexural loads. The test is cheaper, easier to conduct and less
The sleeve diameter seems to affect the tensile capacity of
the connection. However, based on the amount of data
available as obtained from the limited number of specimens,
it is still uncertain whether it is also affecting the
performance of the connection when subjected to lateral loads.
We believe that (a) the eccentricity of the spliced bar in
WBS would have little impact on the bond strength under
tensile load, and (b) the effect could be quite significant for
shear and flexural loads. However, we are unable to confirm
this hypothesis as all the results in this study assume that all
specimens are installed without any eccentricity.
The proposed grouted splice connections are yet to be
tested under seismic, fatigue and constant (creep) loads. At
the current stage, it is still uncertain of their feasibility under
We thank the financial support of Construction Industry
Research Institute of Malaysia (CREAM) and Construction
Industry Development Board (CIDB) through Research
Grant Vot 73713.
This article is distributed under the terms of the Creative
Commons Attribution 4.0 International License (http://
creativecommons.org/licenses/by/4.0/), which permits un
restricted use, distribution, and reproduction in any medium,
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Abd. Rahman , A. B. , Ling , J. H. , & Ibrahim , I. S. ( 2010 ). Performance of grouted sleeve connectors subjected to incremental tensile loads . Malaysian Construction Research Journal (MCRJ) , 6 , 39 - 55 .
AC-133 . ( 2008 ). Acceptance criteria for mechanical connector systems for steel reinforcing bars. Brea:ICC Evaluation Service , Inc.
ACI-117 . ( 1990 ). Standard Specifications for Tolerances for Concrete Construction and Material . ACI Journal. ACI Committee 117.
ACI-318 . ( 2002 ). Building code requirements for structural concrete and commentary . Farmington Hills , MI: American Concrete Institute
Aldin Hosseini , S. J. , & Abd . Rahman, A. B. ( 2013 ). Analysis of spiral reinforcement in grouted pipe splice connectors . Grad¯evinar , 65 , 537 - 546 .
Aldin Hosseini , S. J. , & Abd . Rahman, A. B. ( 2016 ). Effects of spiral confinement to the bond behavior of deformed reinforcement bars subjected to axial tension . Engineering Structures , 112 , 1 - 13 .
Aldin Hosseini , S. J. , Abd . Rahman, A. B. , Osman , M. H. , et al. ( 2015 ). Bond behavior of spirally confined splice of deformed bars in grout . Construction and Building Materials , 80 , 180 - 194 .
Alias , A. , Sapawi , F. , Kusbiantoro , A. , et al. ( 2014 ). Performance of grouted splice sleeve connector under tensile load . Journal of Mechanical Engineering and Sciences (JMES) , 7 , 1096 - 1102 .
Alias , A. , Zubir , M. A. , Shahid , K. A. , et al. ( 2013 ). Structural performance of grouted sleeve connectors with and without transverse reinforcement for precast concrete structure . Procedia Engineering , 53 , 116 - 123 .
Ameli , M. J. , Parks , J. E. , Brown , D. N. , et al. ( 2015 ). Seismic evaluation of grouted splice sleeve connections for reinforced precast concrete column-to-cap beam joints in accelerated bridge construction . PCI Journal , 60 , 80 - 103 .
ASTM A. ( 2005 ). In: ASTM (ed). ASTM A1034/A Standard test methods for testing mechanical splices for steel reinforcing bars . West Conshohocken , PA: ASTM International.
Belleri , A. , & Riva , P. ( 2012 ). Seismic performance and retrofit of precast concrete grouted sleeve connections . PCI Journal , 57 , 97 - 109 .
BS8110- 1 : 1997 . ( 1997 ). Structural use of concrete-Part 1: Code of practice for design and construction BS 8110. British Standards BSI .
E564 -06 A . ( 2006 ). Standard practice for static load test for shear resistance of framed walls for buildings . ASTM International.
Einea , A. , Yamane , T. , & Tadros , M. K. ( 1995 ). Grout-filled pipe splices for precast concrete construction . Precast/ Prestressed Concrete Institute Journal , 40 , 82 - 93 .
Haber , Z. B. , Saiidi , M. S. , & Sanders , D. H. ( 2014 ). Seismic performance of precast columns with mechanically spliced column-footing connections . ACI Structural Journal , 111 , 1 - 12 .
Haber , Z. B. , Saiidi , M. S. , & Sanders , D. H. ( 2015 ). Behavior and simplified modeling of mechanical reinforcing bar splices . ACI Structural Journal , 112 , 179 - 188 .
Hawkins , N. M. , & Ghosh , S. K. ( 2004 ). Acceptance criteria for special precast concrete structural walls based on validation testing . PCI Journal , 49 , 78 - 92 .
Henin , E. , & Morcous , G. ( 2015 ). Non-proprietary bar splice sleeve for precast concrete construction . Engineering Structures , 83 , 154 - 162 .
Jansson , P. O. ( 2008 ). Evaluation of grout-filled mechanical splices for precast concrete construction . R-1512. Michigan: Michigan Department of Transportation MDOT.
Kim , Y.-M. ( 2000 ). A study of pipe splice sleeves for use in precast beam-column connections . Faculty of the Graduate School , The University of Texas at Austin, 116 .
Koushfar , K. , Abd . Rahman, A. B. , & Ahmad , Y. ( 2014 ). Bond behavior of the reinforcement bar in glass fiber-reinforced polymer connector . Gradevinar , 66 , 301 - 310 .
Lin , F. , & Wu , X. ( 2016 ). Mechanical performance and stressstrain relationships for grouted splices under tensile and cyclic loadings . International Journal of Concrete Structures and Materials , 10 , 435 - 450 .
Ling , J. H. ( 2011 ). Behaviour of grouted splice connections in precast concrete wall subjected to tensile, shear and flexural loads (p. 276 ). Skudai, Johor: Department of Structural and Material, Faculty of Civil Engineering, Universiti Teknologi Malaysia.
Ling , J. H. , Abd . Rahman, A. B. , Abd . Hamid, Z. ( 2008 ). Failure modes of aluminium sleeve under direct tensile load . In 3rd International Conference on Postgraduate Education (ICPE-3) . Penang: Sarawak Universiti Sains Malaysia (USM).
Ling , J. H. , Abd . Rahman, A. B. , & Ibrahim , I. S. ( 2014 ). Feasibility study of grouted splice connector under tensile load . Construction and Building Materials , 50 , 530 - 539 .
Ling , J. H. , Abd . Rahman, A. B. , Ibrahim , I. S. , et al. ( 2012 ). Behaviour of grouted pipe splice under incremental tensile load . Construction and Building Materials , 33 , 90 - 98 .
HY , Loh. ( 2008 ). Development of grouted splice sleeve and its performance under axial tension (p. 80 ). Skudai, Johor: Faculty of Civil Engineering, Universiti Teknologi Malaysia.
Rizkalla , S. H. , Serrette , R. L. , Heuvel , J. S. , et al. ( 1989 ). Multiple shear key connections for precast shear wall panels . PCI Journal , 34 , 104 - 120 .
Sayadi , A. A. , Abd . Rahman, A. B. , Jumaat , M. Z. , et al. ( 2014 ). The relationship between interlocking mechanism and bond strength in elastic and inelastic segment of splice sleeve . Construction and Building Materials , 55 , 227 - 237 .
Sayadi , A. A. , Abd . Rahman, A. B. , Sayadi , A. , et al. ( 2015 ). Effective of elastic and inelastic zone on behavior of glass fiber reinforced polymer splice sleeve . Construction and Building Materials , 80 , 38 - 47 .
Seo , S.-Y., Nam , B.-R. , & Kim , S.-K. ( 2016 ). Tensile strength of the grout-filled head-splice-sleeve . Construction and Building Materials , 124 , 155 - 166 .
Soudki , K. A. ( 1994 ). Behaviour of horizontal connections for precast concrete load-bearing shear wall panels subjected to reversed cyclic deformations (p. 656 ). Winnipeg, MB: Structural Engineering Division, Department of Civil & Geological Engineering, University of Manitoba.
Soudki , K. A. , Rizkalla , S. H. , & LeBlanc , B. ( 1995 ). Horizontal connections for precast concrete shear wall subjected to cyclic deformations part 1: Mild steel connections . PCI Journal , 40 , 78 - 96 .
Tastani , S. P. ( 2002 ). Experimental evaluation of direct tension-pullout bond test . In International Symposium Bond in Concrete-from research to standard, Budapest.
Tibbetts , A. J. , Oliva , M. G. , & Bank , L. C. ( 2009 ). Durable fiber reinforced polymer bar splice connections for precast concrete structures . COMPOSITES & POLYCON.
Tullini , N. , & Minghini , F. ( 2016 ). Grouted sleeve connections used in precast reinforced concrete construction-experimental investigation of a column-to-column joint . Engineering Structures , 127 , 784 - 803 .
West , J. S. , Soudki , K. A. , & Rizkalla , S. H. ( 1993 ). Behaviour of horizontal connections for precast concrete load bearing shear wall panels subjected to reversed cyclic loading . Winnipeg, MB: Department of Civil Engineering, University of Manitoba.
Zhu , Z. , & Guo , Z. ( 2016 ). Experiments on hybrid precast concrete shear walls emulating monolithic construction with different amounts of posttensioned strands and different debond lengths of grouted reinforcements . Advances in Materials Science and Engineering , 2016 , 13 .