feasibility of using of steel tube for reinforcement detail...
TRANSCRIPT
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Contemporary Engineering Sciences, Vol. 10, 2017, no. 2, 93 - 101
HIKARI Ltd, www.m-hikari.com https://doi.org/10.12988/ces.2017.610169
Feasibility of Using of Steel Tube for
Reinforcement Detail Simplifying of
RC Coupling Beam
Sun-Woong Kim
Department of Convergence Systems Eng., Chungnam National University
99 Daehak-ro Yuseong-gu, Daejeon, 305-764, Republic of Korea
Young-Il Jang
Department of Construction Eng. Education, Chungnam National University
99 Daehak-ro Yuseong-gu, Daejeon, 305-764, Republic of Korea
Wan-Shin Park
Department of Construction Eng. Education, Chungnam National University
99 Daehak-ro Yuseong-gu, Daejeon, 305-764
Republic of Korea
Corresponding author
Yi-Hyun Nam
Department of Convergence Systems Eng., Chungnam National University
99 Daehak-ro Yuseong-gu, Daejeon, 305-764, Republic of Korea
Hyun-Do Yun
Department of Architectural Engineering, Chungnam National University
99 Daehak-ro, Yuseong-gu, Daejeon, 305-764, Republic of Korea
Corresponding author
Sun-Woo Kim
Department of Construction Eng. Education, Chungnam National University
99 Daehak-ro Yuseong-gu, Daejeon, 305-764, Republic of Korea
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94 Sun-Woong Kim et al.
Copyright © 2016 Sun-Woong Kim et al. This article is distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
Abstract
In this paper investigates feasibility of using of steel tube-filled concrete for
reinforcement detail simplifying of RC coupling beam. In this new connection
system, the steel tube is completely interrupted in the connection zone. In addition,
to investigate the feasibility of using of steel tube for reinforcement detail
simplifying of coupling beam, experiments were conducted for three coupling
beam. The first specimen was made in accordance with the code of ACI 318(11).
The other specimens were made with alternative detail using steel tube-filled
concrete. The test results show the failure mode and hysteretic loop.
Keywords: Coupling Beam, Simplifying of RC coupling, steel tube-filled concrete
1 Introduction
Earthquakes are very dangerous. They exemplify the true power of nature and
cannot be avoided. On 12th September 2016, a strong earthquake of Mw 5.4 hit
Gyeongju in Republic of Korea at 20:33 local time. So, Republic of Korea is no
longer safety zone from the earthquake. Thus, even regions considered safe
seismically over the short term should still insure an adequate seismic design.
Coupling beam have been widely used in high-rise buildings for the last decades
arising from their advanced mechanical and seismic behaviors such as high strength
and stiffness, good ductility and convenience for construction [1].
In addition, reinforced concrete (RC) walls are widely applied in medium-rise
RC building systems in order to resist effectively seismic effects due to their good
stiffness properties and lateral resisting capacity. The concrete coupling beam has
some common shortcomings, including heavy self-weight, low bearing capacity,
insufficient ductility, limited energy dissipation capacity and difficult post-
earthquake reconstruction [2, 3].
As viable substitutes for reinforced concrete coupling beams, the use of steel
coupling beams and composite coupling beams have also been investigated by
several researchers [4-6]. As an alternative to diagonally reinforced concrete
coupling beams, the use of steel coupling beams has also been investigated by Park
et al [7].
This paper proposes a feasibility of using of Steel tube for reinforcement detail
simplifying of RC coupling beam connection to provide capability replace of the
diagonal reinforcement coupling beam connections.
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Feasibility of using of steel tube 95
2 Experimental Programs
Table 1 and Figure 1 show the test variables and specimen details. These three
specimens have identical dimensions and longitudinal reinforcement details [8, 9].
First specimen, C1 was designed in accordance with the seismic design
requirements of the ACI 318-11. Other specimens, C2 and C3 were used to
reinforcement method diagonally reinforcement (steel tube). Steel tube size was
55x55x5t. Figure 2(a) shows the compressive stress of concrete used for each of the
three specimens.
The compressive tests were conducted on the specimens in accordance with the
method defined in ASTM C39 to determine the compressive strength. The
compressive strength of the concrete for specimens is about 34MPa, as shown Fig.
2(a).
The yield and ultimate strengths of the D5 steel, D10 steel and steel tube was
285 MPa, 500 MPa and 264 MPa respectively. In addition, Tensile strengths of D5
steel, D10 steel and cold-formed steel channel was 363 MPa, 576 MPa and 361
MPa respectively, as shown in Fig. 2(b).
Table. 1 Variables of test specimens
Specimen
name
Reinforcement
method Material
Longitudinal
reinforcement Stirrup Diagonal
reinforcement
C1 ACI318-11
Concrete D6-12
D6@50
D10-8
C2 Diagonally
reinforcement
Steel tube
(55ⅹ55ⅹ5t) C3 D6@100
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96 Sun-Woong Kim et al.
(a) C1 specimen (b) C2 specimen
(c) C3 specimen
Fig. 1 Details of test specimens (uint; mm)
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Feasibility of using of steel tube 97
(a) Compression for concrete (b) Tensile stress of steels
Fig. 2 Mechanical properties
The test-setup was shown in Figure 3. The coupling beam was arranged
vertically, and the bottom stub was fixed to the steel frame with bolts. Loading was
imposed horizontally by a hydraulic actuator with a capacity of 1,000kN on the
steel frame connected to the top stub to simulate the behavior of coupling beams
under lateral loads. The data acquisition system consists of 36 to 50 internal controls
and recording channels. Instrumentation was provided to measure the load,
displacement, and strain at critical locations. A cyclic loading used in the vertical
direction of beams wall divided clearly into two phases as shown in Fig. 4. For each
drift loading amplitude, two same-drift consecutive cycles were applied to evaluate
strength and stiffness degradations.
Fig. 3 Test set-up Fig. 4 Loading History
0
5
10
15
20
25
30
35
40
0 0.0005 0.001 0.0015 0.002 0.0025 0.003
Co
mp
ress
ive
str
ess
(MP
a)
Strain
0
100
200
300
400
500
600
700
0 1 2 3 4 5
Te
ns
ile
str
es
s, f s
(MP
a)
Tensile strain es, (%)
D10 steel barFy=500MPa, Fu=576MPa
D5 steel barFy=285MPa, Fu=363MPa
Shape steelFy=264MPa, Fu=361MPa
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98 Sun-Woong Kim et al.
3 Experimental Result
Figure 7 show the cracking and failure mode of specimens. In specimen C1
initial cracking occurred at the bottom beam during the first negative loading cycle
(-50kN). At about 0.5% drift ratio, diagonal cracking occurred in the center. At
about drift 4% ratio, maximum strength was expressed. Final failure mode localized
spalling and crushing of the concrete along the top and bottom beam of the RC
coupling beam in the embedment region was observed in final stage of the tests, as
shown in Fig 5(a). In specimen C2 initial cracking occurred at the bottom beam
during the first negative loading cycle (-50kN). At about 0.5% drift ratio, diagonal
cracking occurred in the top beam. At about 2% drift ratio, multiple shear cracking
occurred in the center. Final failure mode localized spalling and crushing of the
concrete along the center beam of embedment region was observed in final stage of
the tests, as shown in Fig 5(b). In specimens C3 initial cracking occurred at the
center beam during the first positive loading cycle (+50kN). At about 0.5% drift
ratio, diagonal cracking occurred in the center beam. And 3.0 drift ratio, thereafter
severe spalling of concrete in compression occurred at the beam ends. Experiment
results showed that C1 specimen appeared the less destruction than C2 and C3
(a)C1 (b) C2 (c) C3
Fig. 5 Failure mode
Table. 2 Summarizes the maximum strength
Specimen Vu(kN) Average maximum
strength u(%)
C1 (+) 331.94
328.09 4.0
() 324.24 4.5
C2 (+) 313.21
296.30 3.0
() 279.38 3.0
C3 (+) 295.54
293.37 2.0
() 291.19 2.0
Note : Vu(kN)=measured maximum load, u(%)=maximum drift ratio
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Feasibility of using of steel tube 99
specimens. This is because the bond area of coupling beam using channel is smaller
than coupling beam using bundled bars so there is more slipping at interface with
concrete and steel.
Table 2 summarizes the maximum strength (Vu), maximum drift ratio (u).
The hysteretic loop presented in Fig. 6. The hysteretic loop is an important result to
check the seismic behavior of coupling beam elements and usually reflects some
main points such as ultimate resistance capacity, peak-to-peak stiffness and energy
dissipation capacity. In specimen C1 maximum strength (Vu) is to 331.94kN and
maximum drift ratio (u) is to 4.0% in the positive loading direction. In addition,
maximum strength (Vu) is to 324.24kN and maximum drift ratio (u) is to 4.5% in
the negative loading direction. In specimen C2 maximum strength is to 313.24kN
and maximum drift ratio (u) is to 3.0% in the positive loading direction. In addition,
maximum strength (Vu) is to 279.38kN and maximum drift ratio (u) is to 3.0% in
the negative loading direction. In specimen C3 maximum strength (Vu) is to
295.54kN and maximum drift ratio (u) is to 2.0% in the positive loading direction.
In addition, maximum strength (Vu) is to 291.19kN and maximum drift ratio
(u) is to 2.0% in the negative loading direction. C1, C2 and C3 specimens could
be subjected to average maximum strength of 328.09kN, 296.30kN and 293.37kN, respectively. In specimens C1 was 1.11 and 1.12 times larger than those of specimens
(a) C1 (b) C2
(c) C3
Fig. 6 Hysteretic loop
2.5
2.0
1.5
1.0
0.5
0.0
0.5
1.0
1.5
2.0
2.5- 6.0- 5.0- 4.0- 3.0- 2.0- 1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
- 45 - 35 - 25 - 15 - 5 5 15 25 35 45
Vn
(test)/V
n(A
CI
Co
de)
Rotation L(%)
Vn
(test)
, (k
N)
Displacement (mm)
V u=-324.24kN
V u=+ 331.94k
Strong Floor
Rea
ctio
n W
all
Actuator
2.5
2.0
1.5
1.0
0.5
0.0
0.5
1.0
1.5
2.0
2.5- 6.0 - 5.0 - 4.0 - 3.0 - 2.0 - 1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
- 40 - 30 - 20 - 10 0 10 20 30 40
Vn
(test)/V
n(A
CI
Co
de)
Rotation L(%)
Vn
(test)
, (k
N)
Displacement (mm)
V u=-279.38kN
V u=+ 313.21kN
Strong Floor
Rea
ctio
n W
all
Actuator
2.5
2.0
1.5
1.0
0.5
0.0
0.5
1.0
1.5
2.0
2.5- 6.0- 5.0- 4.0- 3.0- 2.0- 1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
- 40 - 30 - 20 - 10 0 10 20 30 40
Vn
(test)/V
n(A
CI
Co
de)
Rotation L(%)
Vn
(test)
, (k
N)
Displacement (mm)
V u=-291.19kN
V u=295.54kN
Strong Floor
Rea
ctio
n W
all
Actuator
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100 Sun-Woong Kim et al.
C2 and C3. It shows that coupling beam made in accordance with the code of ACI-
318 had higher maximum strengths than made with alternative detail using tube
steel-filled concrete. Because of the bond area of coupling beam using tube steel is
smaller than coupling beam using bundled bars so there is more slipping at interface
with concrete and steel. The test results support that tube steel-filled concrete was
not effective coupling beams with steel.
4. Conclusion
Based on the experimental results, failure mode shows that C1 specimen
appeared the less destruction than C2 and C3 specimens. In addition C1, C2 and C3
specimens could be subjected to average maximum strength of 328.09kN,
296.30kN and 293.37kN, respectively. In specimens C1 was 1.11 and 1.12 times
larger than those of specimens C2 and C3. Because of the bond area of coupling
beam using tube steel is smaller than coupling beam using bundled bars so there is
more slipping at interface with concrete and steel.
Acknowledgements. This work was supported by research fund of 2015
Chungnam National University (2015-1149).
References
[1] M. Hassan and S. EI-Tawil, Inelastic dynamic behavior of hybrid coupled walls, Journal of Structural Engineering, 130 (2004), no. 2, 285-296.
https://doi.org/10.1061/(asce)0733-9445(2004)130:2(285)
[2] T. Paulay, Coupling beams of reinforced concrete shear walls, Journal of the Structural Division ASCE, 97 (1971), no. 2, 843-861.
[3] T. Paulay and A. R. Santhakumar, Ductile behavior of coupled shear walls, Journal of the Structural Division ASCE, 102 (1976), 93-108.
[4] B. M. Shahrooz, M. E. Remmetter and F. Qin, Seismic design and performance of composite coupled walls, Journal of the Structural Engineering ASCE, 119
(1993), no. 11, 3291-3309.
https://doi.org/10.1061/(asce)0733-9445(1993)119:11(3291)
[5] K. A. Harries, D. Mitchell and W. D. Cook, Seismic response of steel beams coupling concrete walls, Journal Structural Engineering, 119 (1993), no. 12,
3611-3629. https://doi.org/10.1061/(asce)0733-9445(1993)119:12(3611)
[6] K. A. Harries, D. Mitchell, R. G. Redwood and W. D. Cook, Seismic design of coupled walls-a case for mixed construction, Journal Civil Engineering, 24
(1997), 448-459. https://doi.org/10.1139/l96-130
https://doi.org/10.1061/%28asce%290733-9445%282004%29130:2%28285%29https://doi.org/10.1061/%28asce%290733-9445%281993%29119:11%283291%29https://doi.org/10.1061/%28asce%290733-9445%281993%29119:12%283611%29
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Feasibility of using of steel tube 101
[7] W. S. Park and H. D. Yun, Seismic behavior of steel coupling beams linking concrete shear walls, Engineering Structures, 27 (2005), no. 7, 1024-1039.
https://doi.org/10.1016/j.engstruct.2005.02.013
[8] S. W. Kim, W. S. Park, Y. H. Nam, S. W. Kim, Y. I. Jang and H. D. Yun, The Behavior Characteristics of Link Beam with Alternation of Reinforcement
Details, Journal of KCI Proceeding, 28 (2016), no. 1, 107-108.
[9] S. W. Kim, W. S. Park, Y. H. Nam, S. W. Kim, Y. I. Jang and H. D. Yun, The Failure Mode of Link Beam with Angle of Reinforcement Details, Journal of
KSMI Proceeding, (2016), 143-144.
Received: November 12, 2016; Published: January 3, 2017
https://doi.org/10.1016/j.engstruct.2005.02.013