Feasibility of Using of Steel Tube for Reinforcement Detail ...m-hikari.com/ces/ces2017/ces1-4-2017/p/parkCES1-4-2017-1.pdf2017/01/04 · Feasibility of using of steel tube 97 (a)

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


Wan-Shin Park


99 Daehak-ro Yuseong-gu, Daejeon, 305-764

Republic of Korea

Corresponding author

Yi-Hyun Nam

Department of Convergence Systems Eng., Chungnam National University


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



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.

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


(a) C1 specimen (b) C2 specimen

(c) C3 specimen

Fig. 1 Details of test specimens (uint; mm)


(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


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


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


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


[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

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[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

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Feasibility of Using of Steel Tube for Reinforcement Detail ...m-hikari.com/ces/ces2017/ces1-4-2017/p/parkCES1-4-2017-1.pdf2017/01/04 · Feasibility of using of steel tube 97 (a)