Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Development of High Performance Composite Wall “J-WALL II”
Masashi MICHINO
Civil Engineering Research Dept., JFE Steel Corporation, Kawasaki city, Japan
Email: m-michino@jfe-steel.co.jp

Kunihiko ONDA
Civil Engineering Research Dept., JFE Steel Corporation, Kawasaki city, Japan
Email: ku-onda@jfe-steel.co.jp

Kenji KONO
Building Materials Technology Development Dept., JFE Steel Corporation, Tokyo, Japan
Email: k-kono@jfe-steel.co.jp

ABSTRACTJ-WALL II is a construction method that uses steel sheet piles (product name: Beetle pile) as a temporary retaining wall,then integrates them with the reinforced concrete part after ground excavation to construct a composite underground wall.
Here, "Beetle pile" is a new steel sheet pile formed by joining T-shaped steel and fixing a reinforcing bar to a hat-type
steel sheet pile. A T-shaped steel and a fixing reinforcing bar function as a shear connector when joining the temporary
retaining wall and the reinforced concrete part. Main features of J-WALL II are as follows. 1) Saving construction spaceand shortening construction period. 2) Favorable for construction in a narrow space. 3) Composite wall having excellent
structural performance. In order to confirm the performance of the J-WALL II construction method, we conductedfollowing investigations. (1) It was confirmed that there was no difference in press-in resistance and construction speed
compared with the conventional hat-type steel sheet piles by the installation test of new steel sheet piles for a composite
wall "Beetle pile" by the Silent Pillar (Press-in Method). (2) Strength of the shear connector part of J-WALL II was
confirmed by a punching shear test between the "Beetle pile" and the reinforced concrete part. And we built the design
method of the shear connector part. (3) By a bending test of the actual J-WALL II structural member, we confirmed thatthe wall body can be designed as an integral wall structure (complete composite wall) up to the ultimate limit state.
Key words: Composite wall, steel sheet pile (H-type), Silent Pillar (Press-in Method), Shear strengthwall after excavating the ground, so that it has a thin wall

1. Introduction
Construction of an outer wall of an underground roadthickness, high rigidity and high strength. It is aapproach such as a three-dimensional intersection is often

technology to realize an underground wall. Furthermore,carried out under difficult construction conditions (eg.

it is possible to shorten the construction period and anarrow space, upper obstacles etc.). Normally, after

construction in a narrow space than the existing

constructing a temporary soil fastening wall, a method of

construction method. In this paper, we first describe theconstructing another main wall (mainly an RC structure)technical outline and features of the J-WALL II

has been adopted, but shortening of the construction

construction method. In addition, we report construction

period and cost reduction are desired. The J-WALL II

experiments and structural experiments conducted toconstruction method uses a steel sheet pile for synthetic

confirm the performance of the J-WALL II construction

structure (product name: Beetle Pile) as a temporary soil

method.

retaining wall and integrates it with a reinforced concrete- 185 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

2. J-WALL II construction method

T-shaped steel

2.1. Outline of J-WALL II construction method
The J-WALL II construction method uses a steel

hat-shaped steel
sheet pile

sheet pile for a composite structure (product name: Beetle
Pile) as a temporary soil retaining wall and integrates it

fixing rebar

with a reinforced concrete wall after excavating the
ground (=post constructed RC wall), so that it has a thin

900

wall thickness, high rigidity and high strength. It is atechnology to realize an underground wall (Fig. 1).

Fig. 2(in mm)Outline of Beetle pile

"Beetle pile" is a new steel sheet pile in which a Tshaped steel and a fixing reinforcing bar are welded to a

Axial rebar

Post constructed RC wall parthat-shaped steel sheet pile (Fig. 2). A T-shaped steel, afixing reinforcing bar, and a shear reinforcing bar(penetrating the web of T-shaped steel) are used as a shear

T-shaped steel

shear reinforcing bar

connector with a post constructed RC wall (Fig. 3). With

（Through-hole ）the above function, J-WALL II can demonstrate its

fixing rebar

performance as a strong composite structure up to theultimate limit state. Table 1 shows cross-sectional

Beetle Pile

performance of the Beetle Pile. Hat-type steel sheet piles
JFESP-25H and JFESP-10H are applied to the steel sheet
piles constituting the Beetle pile. The size of the T-shaped

Fig. 3 Section of J-WALL II

steel is based on a flange width of 204 mm and a web
height of 106 mm so as to be compatible with the gripping

Table 1. Cross - sectional performance of the Beetle Pile

structure (chuck) of an existing low vibration / low noise
type hydraulic press-fitting machine. Fig. 4 shows theTypesectional shape of the Beetle Pile.

MomentSectionarea

of inertia

modulus

cm2

cm4

cm3

192.32

41,8362,123

158.31

23,1581,438“B-25H”

2.2. Feature of J-WALL II construction method
Main features of The J-WALL II construction method
are as follows.
① Saving construction space and shortening
construction period

Sectional【T-shaped】+【JFESP-25H】“B-10H”【T-shaped】+【JFESP-10H】

Beetle Pile
T-shaped
steel
Post
constructed
RC wall partFig. 1J-WALL II construction method(in mm)Fig. 4 Sectional shape of the Beetle Pile (B-25H)- 186 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

By using the steel sheet pile as both a permanent

用地境界

structure and a temporary structure, it is possible to reduce

the necessary 用地境界
1600
construction
700 900
site width2900
700 2200

the required width of the work and the thickness of the

Silent Pillar
サイレントパイラー

underground wall compared with the existing construction
method. Therefore, it is possible to effectively utilize the

1100
1100

site. And The construction quantity of the underground900

wall construction and the process can be reduced.

RC part

RC wall
8200②Construction in a narrow spot
It can be constructed by the Silent Pillar (Press-in

Silent Pillar
新設地下斜路Method) as the ordinary steel sheet pile, and it is possible
to construct at a narrow place.
3800③Composite wall
It is an underground wall integrating "Beetle pile"

Beetle pile
ビートルパイルSPSP-Ⅳ
U-4(in mm)and the reinforced concrete part constructed after
excavating the ground, to realize high rigidity and high(a) Existing method

proof strength as a complete composite structure, realizing(b) J - WALL II

Fig. 5 Comparison with the existing construction methoda thin wall.
The comparison between the existing construction

2900 mm .On the other hand, in the J-WALL II

method in which the temporary soil fixing wall and theconstruction method, the construction width is B = 1600

main site bottom wall are constructed with different

mm because it is constructed with an integral wall

structures and the J - WALL II construction method are

structure of Beetle Pile and Reinforced Concrete Wall (t =shown in Table 2 and Fig. 5. In the existing construction

900 mm). Therefore, it can be reduced by 55% comparedmethod, after using the U-shaped steel sheet pile IV as awith the existing construction method.

temporary soil closure, a cast-in-place reinforced concrete
wall (t = 1100 mm) is constructed as the main wall, and3. Installation test of Beetle Pile

finally the necessary construction site width becomes B =3.1. Outline of Installation test
In order to confirm the workability of the Beetle Pile,

Table 2. Comparison with the existing construction method

we conducted an installation test and compared it with a(a) Existing

conventional hat-shaped steel sheet pile. The Beetle pile(b) J - WALL II

methodused for the test consists of a hat-shaped steel sheet pile

Temporary soil

Steel sheet pile

Beetle Pile

(25 H) and a T-shaped steel (106 × 204 × 12 × 18), and its

retaining wall

U shaped-4

B-25H

length is L = 15 m. For further comparison, a hat-shaped

cast-in-place

Integral wall ofsteel sheet pile (25 H) L = 15 m was also prepared. The

Permanent

reinforced

Beetle Pile andtest number and test conditions are shown in Table 3. The

Wallconcrete wall

RC Wallappearance of the Beetle pile is shown in Photo 1. The(t=1100mm)(t=900mm）

installation test was carried out by Press-in Method（Silent

The following

Pillar ECO900 / Power unit EU 300）. SP No. ① and ②

steps can be(Joint Fitting: ×) were installed as single pile. Other SPomitted.

No. (Joint Fitting: 〇) were installed while fitting・Assembly andof next sheet pile installed previously. In the installation

dismantling of

test, the Press-in force, installation time and available

Construction
periodouter scaffold
and formwork
・Backfillprocess

joint

length were measured. The situation of the press-in
installation test is shown in Photo 2. Fig. 6 shows theBoring log of the installation test site (the groundwaterlevel is deeper than GL - 25 m). The ground composition- 187 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochiof the press-in installation test site is a soft loam / clay
layer from the surface layer to the depth of about 10 m.
However, at depths of more than 10 m, it becomes a tightfine sand layer, and the press-in resistance increases. And
it was expected that installation will be difficult.
3.2. Result of Installation test
The results of press-in installation test on Beetle Pilesand hat-shaped steel sheet piles are shown in Table 4. The

Photo 2. Situation of installation

length that could be finally cast by the press-in machine

試験場所：千葉県稲毛区
試験場所：千葉県稲毛区

the Beetle piles is the same level as the workability of thehat -shaped steel sheet piles. Fig. 7 shows comparative

5

examples of press-in resistance (press-in force) of Beetle
Piles and hat-shaped steel sheet piles. It can be seen thatin each case with or without joint fitting, the press-in

埋土

ローム

ローム

粘土質
4.8
/Clay
ローム
5.2
疑灰質
粘土
7.3

粘土質
ローム
疑灰質
粘土

細砂
fine
sand

細砂

Loam

10

4.8
5.2
7.3
7.7
8.35
9.25
10.75

5

H25

10 20 30 40105020 30 40 50

1.0
埋土

1.0

粘土
粘土
7.7
粘土混細砂
8.35
粘土混細砂
Clay
細砂
細砂
9.25
mixed
10 fine
粘土混
粘土混
sand
細砂
細砂
10.75

15,000sec. From these facts, it was found that the workability of

土standard
標準貫入
標準貫入
質
penetration
試験
区試験
test
分
Ｎ値N
Ｎ値 H25SPT

15,00010 m (loam / clay layer) (casting time) was 300 sec - 400

標 深 柱
標 深土 柱質
尺 度 状
尺 度区 状
分
ｍ ｍ 図
ｍ ｍ 図
Soil classsheet piles. Furthermore, the arrival time to the depth ofLevel (m)was about 12 m for both the Beetle piles and the hat steel

resistance of Beetle Piles and hat-shaped steel sheet piles
at each casting depth were about the same.

15

15

Table 3. Condition of Installation test
SP

Length

joint

No.

of SP

fitting

Hat

①

15.0ｍ

×

shaped-25H

②

15.0ｍ

〇

③

15.0ｍ

〇

④

15.0ｍ

〇

Beetle Pile
B-25H

⑤

15.0ｍ

〇

⑥

15.0ｍ

〇

⑦

15.0ｍ

〇

⑧

15.0ｍ

×

⑨

15.0ｍ

〇

20

20
21.0

21.0

fine

25

25

細砂
sand

細砂

Fig. 6 地下水位はG.L.-25m以深Boring log of the installation test site
地下水位はG.L.-25m以深
Table 4. Result of Installation test
lengtharrival time

fitting

could beto the depth

finally castof 10 m

Hat

①

×

12.5m

380sec

②

〇

12.1m

280sec

③

〇

11.4m

434sec

④

〇

12.4m

329sec

⑤

〇

11.6m

413sec

⑥

〇

11.1m

418sec

⑦

〇

11.1m

276sec

⑧

×

11.8m

321sec

⑨

〇

13.0m

324sec

B-25H- 188 -

joint

shaped-25H

Beetle Pile

Photo 1. Beetle pile

SP
No.

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Press-in force （kN）
0 200 400 600 800

Press-in force （kN）
0 200 400 600 800
0

4
6
8
10

shear reinforcing bar (sum of four bars) and the0

Hat-25H
Beetle Pile

2
Casting depth （m）

Casting depth （m）

2

shear reinforcing bar is D25, the tensile yield load of theHat-25H
Beetle Pile

experimental shear strength increment (Case D0-F30 shear
strength subtracted) correspond to 1: 1. In the case of D25,

4

one-sided shear failure of the concrete eventually occurredalong the position of the reinforcement (Photo 5). It seems

6

that destruction progressed in the following process, and8

the Shear strength increment became small.

10

occurrence of split crack → ② reduction of adhesion①

and binding force of reinforcing bars → ③ occurrence
12

12

14

14

shear reinforcing bar and concrete reached limit before(b) without joint fitting

shear reinforcing bar got yield in the case of D25.

(a) joint fittingof one-sided shear failure. It means that bonding between

Fig. 7 Press-in force of Beetle Pile and hat-25H

4. Shear strength of the shear connector part of JWALL II
4.1. Outline of punching shear test
A punching test was conducted to evaluate theintegrity of the steel sheet piles and the post constructed
RC wall (Photo 3). The specimen had a symmetrical shapewith two steel sheet piles facing each other so that it could

Photo 3. Punching shear test

push evenly. The bottom end of the steel sheet pile and T
shape steel was preliminarily box-pulled out, only theconcrete was grounded, and at the upper end only 150 mmof the steel sheet pile protruded, and we applied it here
(Fig. 8). Table 5 shows test specimen conditions andexperimental results (shear strength). In this experiment,
we mainly checked the influence of shear reinforcing bar(penetrating the web of T-shaped steel) sizes and theconcrete strength. In each of the cases, two fixing bars
were installed in the web of the steel sheet piles (singlesided flare welding).
4.2. Result of punching shear test
The test results are shown below.
(1) Failure modeIn either case, the shear strength decreased after shear
failure of one side of the concrete from the tip of the Tshaped steel flange to the end of the steel sheet pile web.
On the other hand, adhesion performance around thefixing rebars was maintained, and removal of thereinforcing bars was not observed (Photo 4).
(in mm)(2) Influence of shear reinforcing bar size
According to Fig. 9, except for the case where the- 189 -

Fig. 8 Specimen of punching shear testProceedings of the First International Conference on Press-in Engineering 2018, Kochi

concrete compressive strength increased from 29.3 ( D19-

Table 5. Case of I punching shear test
Concrete

ShearF30) to 38.2 N / mm 2 (D16-F40), an increase in shear

reinforcing

compressive

strength

strength could be confirmed but the strength ceased at 47.8

barstrength (MPa)(kN/m)

N / mm 2 (D16-F48).

Shear
Case
D13-F30

D13

D16-F30

D16

D19-F30

D191521

D25-F30

D251670

D16-F40

D16

38.2

1721

D16-F48

D16

47.8

1767

D0-F30

No

29.0

1260

4.3. Evaluation method of 4. Shear strength of the

1412

29.3

shear connector partWe evaluated the shear strength of the shear
connector part of J-WALL II (converted to per meter
length of beetle pile) by applying the concrete joint
strength type equation (case of integral casting) derived

1009

reinforcementfrom Okada's research1). Fig. 11 shows the comparison of
the concrete joint strength formula (in the case of integral
casting) presented in Eq. (1) in Okada's research 1) withthis experimental result. Except for the case of the shear
reinforcing bar D25, it was confirmed that the

1000
800

2500

2000

2000

1500
1000

In either case, shear
reinforcing bar is D19

500
0

600

D25
D19

400

30
40
50
Concrete compressive strength (MPa)Fig. 10 Relationship between concrete compressive strengthand shear strength

0
0

200

400

600

800

1000

Tensile yield load of the shear reinforcing bar(sum of four) （kN）

Fig. 9 Strength increment by shear reinforcing bar

1.4

No reinforcement

1.2

Shear reinforcing
bar is D13
D13
D16

1.0

D19
0.8

Shear reinforcing
bar is D25
D13

0.6

20
30
40
50
Concrete compressive strength (MPa)Fig. 11Comparison of Experimental shear strength andstrength formula valueQs  0.18 L T L H  f ' ck  1.33 n sc  A sc  f spyk

Photo 5. Failure mode (case of D25-F30)(1)

LH : Shear section length (adhesion length) (mm)(3) Influence of Concrete Strength
Fig. 10 shows the relationship between concrete
compressive strength and shear strength. When the- 190 -

1000
500

2

D16
D13

200

1500

0

20

Experimental shear strength /1）strength formula value

Experimental shear strength
increment (kN)

Photo 4. Failure mode

2500
せん断耐力(kN/m)Shear strength (kN/m)

D19最大
experimental result exceeds thestrength formula value.

LT : Shear fracture surface length of concrete,
The web height of the T-shaped steel × √ 2
may be used (mm)Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

75110110 180

However, ≤ 45 MPa

Axial rebar
7-D16
Shear reinforcing bar
D19 （200 mm pitch）

Asc : Cross sectional area of shear reinforcing
bars (per one) (mm2)

180 11011075

However, ≤ 286.5 mm2

nsc : Number of shear reinforcing bars in the shear

Axial rebar
2-D16

sectionf spy : Characteristic value of tensile yield strength of

301.8 100 220 80

f ' c : Concrete design standard strength (MPa)T-shaped steel
204×105mm

80 80
Fixing rebar
D19
Hat shaped-25Hshear reinforcing bars (MPa)

(mm)

950

5. Evaluation of structural performance of composite

Fig. 13 Sectional view of the specimen (bending test)

wall J-WALL II
RC wall part5.1. Bending test of J-WALL II structural member
In order to confirm that the wall composed by the
Beetle pile and the post constructed RC wall part behave
as a synthetic structure, a bending test of a real size wascarried

Rectangularsteel tubes

out. In the test, a total of 2 cases were carried out: aBeetle Pile

positive bending test C1 (the steel sheet pile positioned on
the tensile edge side), and a negative bending test C2 (aPhoto 6. Bending test of J-WALL II

steel sheet pile was positioned on the compressed edgeside). The outline of the specimen is shown in Fig. 12, and5.2. Result of bending test

the sectional view of the specimen is shown in Fig. 13.

Table 6 shows the material strength and the test result

The cross-sectional height of the post-constructed RC wall

(maximum load). Fig. 14 shows the relationship between(height from the steel sheet pile web position) was 40 cm.
The test method was a 4-point bending test, and theTable 6. Material strength and test result of bending test

distance from the fulcrum to the loading point (shear span)

Material strength (MPa)was 3.5 m. In consideration of the restraint of concreteCasemovement in the wall extension direction (horizontal
direction) in the underground wall structure, we

950

80 80

145 145

Load (kN)

4200

301.8 100 220 80

950

180 110110 75400

301.8 50 280 70

301.8

180 11011075

80 80

145 145

9000

365

Maximum
load
（kN）
1368
756

D19(SD345)

800

301.8 100 220 80

Crushing of concreteMax. 1368kN▼
Ultimate strength
1285kN (calculated)
Mｙ 964kN Beetle Pile
Yield
strengthyields880kN(calculated)400

loading point

loading point180 11011075

1200

D19(SD345)

950

fulcrum

3500(a) positive bending test C1

326

25.6

1600

75110110 180

Shear span 3.5m

4200

Yield
strength ofaxial rebar

Test result

D16（SD345） D16（SD345）
75110110 180

RC wall part
Beetle Pile
1400
9000

Yield
strength ofsteel sheet
pile

ｽﾀｰﾗｯﾌﾟD13
D16（SD345） D16(SD345)

22@200=4400

1.4m

950

80 80

loading point
D16（SD345）

3500

28.0

C2

4200
9000

loading point

fulcrum Shear span 3.5m

145 145

180 11011075

180 11011075

950

C1

75110110 180

4200

specimen (Photo 6).

75110110 180

steel tubes and constrained the lateral deformation of the

80 220 100 301.8

75110110 180

sandwiched the specimen using two pairs of rectangularConcretecompressivestrength

D16(SD345)

D19(SD345)
950

D19(SD345)

3500

22@200=4400

Shear span 3.5m fulcrum
D16（SD345）

1.4m
1400

D25（SD345）

3500

D16(SD345)

301.8
400

80 220 100 301.8

Beetle Pile
RC wall part
fulcrum Shear span 3.5m

70 280 50 301.8

145 14580 80

075110110 180

180 110110 75

D16（SD345） D25（SD345）
ｽﾀｰﾗｯﾌﾟD13

40
80
120
160
Deflection of the center position of the specimen (mm)(a) positive bending test C1

9000(b) negative bending test C2

0

Fig. 14 Relationship between the load and deflection of thecenter position of the specimen

Fig. 12 Outline of the specimen (bending test)- 191 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Load (kN)

Ultimate strength
707kN (calculated)▼
Axial rebar
yields600

Mｙ 404kN

400
200

Yield strength
329kN(calculated)

0
0

50
100
150
200
250
Deflection of the center position of the specimen (mm)(b) negative bending test C2

試験(compressed edge)

800

700

Sheet pile
Concrete
Axial rebar
T-shaped

600

600
500

座標（mm)

Max. 756.2kN

800Buckling occurs (Beetle Pile)

Distance from Beetle pile arm part （mm)

1000

400

200

Fig. 14 Relationship between the load and deflection of the

400
300
200
100

0
-1500 -1000 -5000500Strain (μ )center position of the specimen

0
-5000

1000 1500 2000

(tensile edge)(a) positive bending test C1(tensile edge)

specimen. In the figure, the yield strength and ultimate
strength calculated on the assumption of a perfectsynthetic structure (Navier hypothesis) are shown. Steelsheet piles, concrete, axial rebar were modeled taking
material nonlinearity into account.
In both cases, the experimental values exceeded thecalculated values, and it was confirmed that they possess
sufficient structural performance. Fig. 15 shows the strain
distribution in the material axis direction at the yield load

800

700

600

400

Sheet pile
Concrete
Axial rebar
T-shaped

200

0-1500 -1000 -5000500Strain (μ )of the positive bending test C1. Since the strain
distribution shows that the condition of Navier hypothesis

1000

1500

2000

(compressed edge)(b) negative bending test C2

is established, it can be confirmed that it behaves as a

Fig. 15 Strain distribution in the material axis direction at

perfect synthetic structure.

the yield load

Regarding the fracture behavior of each test
specimen, in the positive bending test C1, the load was(2) Strength of the shear connector part of J-WALL II

decreased due to crushing of concrete in the central part ofwas confirmed by punching shear test between the "Beetle

the specimen, but the load did not decrease sharply. In thepile" and the reinforced concrete part. And we built anegative bending test C2, the load gradually decreased

design method of the shear connector part.

with the progress of buckling of the steel sheet pile in thecentral part of the specimen.

(3) By the bending test of the actual J-WALL II
structural member, we confirmed that the wall body canbe designed as an integral wall structure (complete

6. Concluding remarks
In order to confirm the performance of the J-WALL

composite wall) up to the ultimate limit state.

II

References
1) Okada, T. 1994. Study on shear transfer acrossconstruction

method,we

conducted

variousperformance confirmation experiments and obtained thefollowing results.

concrete joint interface. Journal of Japan Society of(1) It was confirmed that there was no difference inthe press-in resistance and the construction speed
compared with the conventional hat-type steel sheet piles
by the installation test of new steel sheet piles for acomposite wall "Beetle pile" by the Silent Pillar (Press-in
Method).

- 192 -

Civil Engineers, No. 502/V-25, pp. 73-82.

鋼矢板アーム部からの距離（mm)Distance from Beetle pile arm part （mm)the load and the deflection of the center position of the

600
500
400
300
200
100
0
-6000