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

Overview of the Self-standing and High Stiffness Tubular Pile Walls in Japan
Tomoko MIYANOHARA
Construction Solutions Department, GIKEN LTD., Tokyo, Japan
Email: miyanohara@giken.com

Tatsuaki KUROSAWA
Senior Manager, Construction Products Development Div., Nippon Steel & Sumitomo Metal Corporation, Tokyo, Japan

Noriyoshi HARATA
Senior Manager, Construction Products Development Div., Nippon Steel & Sumitomo Metal Corporation, Tokyo, Japan

Kazuhiro KITAMURA
Assistant Manager, Construction Headquarter, GIKEN SEKO CO., LTD., Tokyo, Japan

Naoki SUZUKI
Construction Solutions Department, GIKEN LTD., Tokyo, Japan

Koji KAJINO
Department Leader, Press-in Technologies Support Department, GIKEN LTD., Tokyo, Japan

ABSTRACTThe equi-distantly pressed-in self-standing steel tubular pile retaining walls (hereinafter referred to as steel tubular wall(s))
are column row structures. They are often adopted where the construction yard is limited and when the construction
schedule is tight, since they can be installed in smaller construction yards, compared with other structures such as gravity
type walls and those with inverted T-type footings. The Press-in Method is suitable for space-saving constructions, andthe applications of self-standing steel tubular walls with high stiffness are increasing, since a rotary cutting press-in
machine that can press-in large diameter steel tubular piles has recently been developed, enabling its application of themethod to taller walls.
This paper presents an overview of the design methods of the self-standing steel tubular walls, along with the site
conditions, surrounding environments and the details and reasons for their adoptions in the 3 projects where self-standing
steel tubular walls with high stiffness were used. The walls are generally designed using a beam expressed by a linear
spring element on a floor that can be regarded elastic in semi-infinite domain, following the guidelines and manuals forother structure types (e.g., Advanced Construction Technology Center, 2006; IPA, 2017). With the increase in diameter,secondary moment of inertia and stiffness of steel tubular piles tend to become larger, consequently to make the embedded
length longer. Three case studies presented here are all for road retaining walls, and they clarified the construction
constraints such as limited construction yard, construction in stiff ground and limited construction time. The features of
the wall structures and advantages in the press-in operation together with the points of attention are addressed throughthese case studies, sorting out the future issues thereby.
Key words: retaining wall, self-standing wall, steel tubular pile, high stiffness, narrow space

the number of structures over 50 years will increase

1. Introduction
Many kinds of infrastructures such as roads, bridges
and river embankments were constructed after the period

therefore renewal construction will further increase
throughout Japan.

of high economic growth. In the future, it is expected that- 167 -

Nowadays constructions of the equi-distantlyProceedings of the First International Conference on Press-in Engineering 2018, Kochi

pressed-in self-standing steel tubular walls are increasing

well as river levees. The constructions of steel tubular

for urban river renovation works and road widening works.

sheet pile or steel sheet pile earth retaining walls follow

The self-standing steel tubular walls are different fromexisting standards (e.g. Japan Road Association (JRA),

usual inverted-T shaped or gravity walls, since there needs

2012; The Ports and Harbours Association of Japan, 2007;

to be no footing, and required site areas can be smaller. In

Public Interest Incorporated Association of Nationwide

addition, unlike cast-in-place piles, prefabricated steel

Disaster Prevention, 2017).

tubular piles can be used. Advantageous points may be

Recently applications of steel sheet pile walls to roadthat construction can be carried out with high quality in aworks have increased. In the above JRA guideline of theshort period of time. In particular, self-standing steel

retaining walls for road works, steel sheet pile walls aretubular walls are highly evaluated in the works such as

categorized in “other earth retaining walls”, and there aredisaster restoration works and those with limited

no descriptions of design and construction. The guideline

construction time, since it is possible to construct the walls

describes the earth retaining wall as one selected in a sitewith fewer construction types/stages. In the past, steel

with strict construction conditions from the effects on the

tubular piles with a diameter of 1,000 mm or so wereadjacent construction or those on current traffic andmainly used for the construction of road retaining walls.

surrounding environments, when there is no extra space in

However, use of steel tubular piles with larger diameters

the construction site, and/or ground excavation is difficult.

of, e.g., 1,500 mm or 2,000 mm is increasing in these days

The height of the wall is generally lower thanwith the increase in the types of construction machines

approximately 4 m, and the walls are often applied inavailable.

relatively firm sandy soil or hard clayey soil. On the otherAs a construction method used for the installation ofhand, the design method of steel sheet pile walls for roadself-standing steel tubular walls in narrow urban areas, thework is suggested in the “Design manual of self-standing

Press-in Method, especially the Gyro Press (Rotarysteel

cutting) Method, is often used. It is a suitable method forTechnology Center (ACTC), 2006), and the required

construction sites under strict constraints in urban areas.

performance is prescribed, as shown in Table 1. Note that

Installing cutting bits at the pile toe, the steel tubular pilethe standard is applicable only for walls lower thancan penetrate not only stiff ground but also boulders andapproximately 4 m.

sheet

pile

walls”(Advanced

Construction

existing concrete structures. For this reason, it isapplicable even without removing the existing structure(s).

Table 1. List of detailed investigation items for the required

This paper presents an overview of currently used self-

performance of steel sheet pile walls

standing steel tubular walls, together with the site
reasons for the adoption of the method in the cases of the
3 construction projects where the large-diameter steel

Stability of steel tubular sheet piles/piles retaining wall

Necessary
performance

conditions, surrounding environments and the process andtubular walls were used. The features of the wall
together with the points of attention are addressed throughthese case studies, sorting out the future issues thereby.

Performance 1

structures and advantages in the press-in operation

Perform
ance 2

2. Existing design method
2.1. Design method of self-standing steel sheet pile

structures made of steel may include steel tubular sheet
pile walls and steel sheet pile walls. They are both often
used for quay walls, temporary earth retaining walls, as- 168 -

Perform
ance 3road retaining walls in Japan
Similar to steel tubular walls, self-standing wall

Stability of steel
tubular sheet
piles/piles
retaining wall
itselfUsabilityof
Stability of ground on the passive surrounding
facilities
side in front of the retaining wall

Horizontal displacement of steel
tubular sheet piles/piles retaining
Stress ≤ Normal wall on the design ground surface
Horizontal
allowable stress or≤ displacement at which thedisplacement atallowable stress at horizontal resistance of ground at
top ≤the time ofthe embedded portion of steel
allowable
earthquake
tubular sheet piles/piles retaining
displacement
wall can be considered elastic
geotechnically
Horizontal
displacement at
top ≤allowable
There is an elastic area in thedisplacement
Stress ≤ yield
ground at the tip of embedded
stressportion of the wallProceedings of the First International Conference on Press-in Engineering 2018, Kochi

suggested by IPA (IPA, 2017), and, as shown in Table 2,

2.2. Current design method of self-standing steel
tubular retaining walls
In the case where land acquisition is difficult for river

it is in compliance with the “Manual of self-standing steel

levee restoration works and existing road widening works

the allowable deformation in performance 1 is given by

in urban areas, or in the case where there is an existingreference to the ACTC’s value, while it suggests to

structure adjacent to a construction site and it is necessary

determine the allowable deformation separately into remove existing concrete structures, steel tubular walls

reference to the conformity standard mentioned in section

with high stiffness constructed by means of the Gyro Press

2.1, in the case where the wall is higher than 4 m.

sheet pile walls” (ACTC, 2006). In the IPA’s suggestion,

Method may be used as an applicable construction method.
Application of the Gyro Press Method is increasing in

Table 2.

actual projects, since it has a function of excavating

Outline of conformity standard of self-standing steel
tubular walls

ground, and facilitates installation of column row steel
tubular walls in stiff ground. Both in river levee and roadretaining wall works, the design is carried out mainly with

Applied wall height

Height of steel sheet pilewall less than about 4 m(road works)

Structure calculation
method(Performance 1) Simplified method: beamspring (ground) model(Performances 2&3) Elasto-plastic method or
dynamic analysis

a simplified ground reaction model and the calculation ofembedded length, in which the deformation and stress are
examined in detail and the necessary length of the steel
Selection ofcoefficient ofground reaction

tubular piles are determined. In the calculation model
where a beam is simulated by a linear spring model on an
the embedded length is determined from the correlation of
the ground stiffness with the pile stiffness. As can belength of 𝑙0 tends to become larger, since the larger the
diameter of steel tubular pile is, the larger the moment ofinertia as well as the stiffness becomes. Note that it is𝑘𝐻 = 𝑘𝐻0 (𝐵𝐻 −3/4)
0.3

Selection of design
ground surface

Design ground surface = front ground surface

Calculation ofembedment length3/βAllowable
displacement

inferred from Eqs. (1) and (2), the necessary embedded

Design for performance 1

elastic floor, assuming that the pile is semi-infinitely long,

Press in retaining
structures: ahandbook

Design Manual of selfstanding steel sheet pile

Normalcondition

Lateral displacement at the top of steel sheet
pile: less than 1 % of wall height, and lateraldisplacement on the design ground surface: lessthan 15 mm.

Underseismiccondition

Lateral displacement at the top of steel sheet
pile: less th.5an 1 % of wall height, and lateraldisplacement on the design ground surface: lessthan 15 mm.

necessary to ensure the embedded length of 𝑙0 to be 2.5/β
for temporary structures, and 3/β for actual structures.

3. Case studies
In this section three construction cases with large

𝑙0 =

3
𝛽

4 𝑘 𝐵

β =√ 𝐻

4𝐸𝐼

diameter self-standing steel tubular walls are introduced.

(1)

3.1. Case study 1(2)This project is a road-widening work in order tosecure sidewalks on a two-lane major road which

β: characteristic value of pileconnects major cities, in which the outline of thekH: coefficient of subgrade reaction (kN/m3)

construction of a 13 m-high road retaining wall on a

B: unit width of steel tubular earth retaining wall (=1m)

slope is summarized in Table 3.

l0: effective embedment depth of pile (m)E: Young’s modulus of steel tubular earth retaining wall

Table 3. Overview of project
Purpose of Project
Road retaining wall
Pile Section &dia. =2,000mm, t=20mm, L=20 toLength24m, n=12
Duration
February 1, 2018 to April 30, 2018

(kN/m2)
I: secondary moment of area per unit width of steel
tubular earth retaining wall (m4)
The design method of self-standing steel tubular walls
constructed by means of the Gyro Press Method is- 169 -

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

3.1.1. Site and ground conditions
The site was on a slope close to the boundary

the soil movement behind the wall was restricted. In

between a terrace and a river (Figs. 1 and 2). The slope

piles. The types of construction work were minimized by

was between a major road and a residential area with theusing cladding panels on the front side of the steel tubularlargest elevation difference of 13 m. In the case of thepile walls. The construction work of the piles for an

construction of the road wall, it was necessary to pay

extension of approximately 30 m was thus completed in a

attention to the effect on the major road and theperiod of 89 days. (Figs. 3 and 4).

addition, drain pipes were installed between steel tubular

surrounding crowded houses.
The site ground was consisted of a sand and gravel
layer with clay. The converted Standard Penetration Test
(SPT) N-value was calculated using Eq. (3) shown below(Japanese Geotechnical Society Standards, 2013). The
maximum N-value was 500.

𝑁 = 50 ×

0.3
𝛿𝑧𝑆𝑃𝑇,50(3)

N: SPT N-value
𝛿𝑧𝑆𝑃𝑇,50 : the penetration depth of the SPT sampler in

Fig. 1

Cross section of retaining wallmeter at the blow count of 50 (m)3.1.2. Reason for selection of self-standing steel
tubular walls
In the original design, the ground-anchor type walls
were selected equivalent to the existing road retaining
walls. However, since the use of the residential area waslimited, the structure type of the walls had to be reviewed.
For comparison with the self-standing walls, the caisson
pile walls, the cast-in-place pile walls and the steel tubular
pile walls were considered. Making a comparative review

Fig. 2 Photo taken prior to constructionof the aforementioned methods, it was found that, in termsof the construction cost, the ratio of the steel tubular walls
to the caisson pile walls was 1:0.6, and that of the cast-inplace pile walls was 1:0.6. On the other hand, in terms ofthe construction period, the comparison was 1:6 for thecaisson pile walls, and 1: 8 for the cast-in place concrete
pile walls. After consideration of these studies, the steel
tubular pile walls, which would facilitate the construction
in a shorter period, were highly evaluated and adopted.
3.1.3. Structural type and piling method
A cross section of a self-standing steel tubular wallis shown in Fig. 1, and the material used is summarized inTable 3. The steel tubular piles were connected bywelding plates between each two adjacent piles. This way- 170 -

Fig. 3 Photo taken during pressing-in steel tubular pileProceedings of the First International Conference on Press-in Engineering 2018, Kochi

construction site. As a result, the steel tubular walls wereapplied from the points of both construction period andcost. In addition, although the pile installation by either avibration hammer or inner excavation were also
considered for installing steel tubular piles, judging fromthe narrow space on stiff ground, the only possible
method that could be applied to the site was the Gyro

New Road

Press Method.
3.2.3. Structural type and piling method
The cross section of the self-standing steel tubular

Fig. 4 Photo taken during construction of cladding panels

wall is shown in Fig. 5, while the pile material used is

3.2. Case study 2This is a road widening project from 2 to 4 lanes onoutlined in Table 4. The construction was carried out,a major road with heavy traffic to reduce traffic jams andcreating a construction yard of a maximum width of 15 m

traffic accidents. A sloped ground adjacent to the road wason the primarily excavated ground (Fig. 5). Afterto be excavated and a road retaining wall with a height ofpressing-in the steel tubular piles, the secondary

11.5 m was to be constructed, while allowing the traffic

excavation was made so that the ground in front of theon the road. An overview of the project is summarized insteel tubular walls was excavated down to the designed

Table 4.

elevation of the widened road, and then the road surface
was paved. The front side of the steel tubular walls wascovered with cladding panels. The construction of theTable 4. Overview of the project
Purpose of Project Road retaining wall
Pile Section &dia. = 2,000mm, t=20mm, L=24.5 toLength
27.5m, n=44
Duration
July 26, 2016 to October 22, 2016

piles was completed in a period of 89 days for an
extension of 100 m (Figs. 7 and 8).

3.2.1. Site and ground conditions
The construction site was located on a slope between
a major road in a dense residential area and a cemetery(Figs. 5 and 6). The cemetery was at the top of the slope
and the construction yard was surrounded by residential
houses. For this reason, the effect on surrounding areasfrom the construction method required should be
minimized. The first 8 m from the ground surface in thesite consists of a loam layer, underlain by clayey fine sandFig. 5

Cross section of retaining walllayer. The converted N-value of the lower clayey fine sandlayer was approximately 125.
3.2.2. Reason to select self-standing steel tubularwalls
It was necessary to excavate the slope adjacent tothe construction site and construct an 11.5-meter-highroad retaining wall, while allowing the traffic on theroad. The self-standing steel tubular walls and thecaisson pile walls were compared and examined as towhich was a suitable structural type for a limited space

Fig. 6 Photo taken prior to construction- 171 -

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

Fig. 7 Photo taken during construction
Fig. 9Cross section of the wall

3.3.2. Reason to select self-standing steel tubularwalls
As a construction type that could be applied to anarrow construction space adjacent to a road, a selfstanding steel tubular walls by the Gyro Press Method was
adopted. As other construction types, also consideredwere the steel tubular wall by the inner excavation methodby means of a combination of a temporary platform and acrane type, and the PC wall structures by means of a

Fig. 8 Photo taken after construction

combination of a temporary platform and inner excavation.
3.3. Case study 3
The project was a reinforcement work of a slope

The construction cost of the steel tubular walls was similar

surface along an express way in a mountainous area. It

considerations, it was found that if the Gyro Press Method

was required to construct a 10.5 m high earth retaining

with the GRB system were used, in which all the pilingwall. An outline of the project is summarized in Table 5.

works could be completed on the previously pressed-into that of the PC wall structures. As a result of

pile tops, use of a temporary platform would become
unnecessary, and that the machine weight could be

Table 5. Overview of the project
Purpose of Project Road retaining wall
Pile Section &dia. = 1,500mm, t=25mm, L=24.0 to
Length26.0m, n=54
Duration
December 9, 2011 to April 11, 2012

relatively small, and use of heavy cranes could be avoided.
Because of these advantages, the Gyro Press Method with
the GRB system was selected as the construction method
suitable for the project.

3.3.1. Site and ground conditions
The site was located along the side road of an express
way. Since box culvert structure was buried underneath

3.3.3. Structural type and piling method
A cross section of a self-standing steel tubular wall

the side road, the weight of the machine that could be usedis shown in Fig. 9, while the piles used are outlined in

was limited to 20 to 30 tons (Fig. 9). In addition, theTable 5. It was possible to carry out the construction by

construction had to be completed by the time the express

the GRB system in a situation where heavy cranes could

way was put into use.

not be used, without hindering the upper structure work of

The site ground consists of sand and gravel layer

the express way.

The construction of the piles waswith occasional boulders, underlain by stiff ground with acompleted in a period of 125 days for the extension of 100

converted N-value of approximately 300.

m (Figs. 10 and 11).

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

4. Conclusions
Through the construction cases described in this paper,
the following merits can be pointed out for the structures ofself-standing steel tubular walls with high stiffness:
1) It is a structure type suitable for the application to
narrow space with strict construction limit, since it isa direct wall structure and requires only small
construction yards; and2) Since prefabricated piles are used for the construction,
types of works as well as construction stages can be
fewer and the construction time can be shorter.

Fig. 10 Photo taken during construction

In addition, the following advantages and points ofattention during press-in operation may be listed:
1) The Gyro Press (Rotary cutting) Method can copewith stiff ground; and
2) The press-in operation is possible in a narrow space,since the press-in machine can be operated on the topof the piles already pressed-in, and a temporary
platform is not required.
One of the future challenges may be to establish amore rational design method. Currently there are noFig. 11 Photo taken after construction

existing design standards that systematically prescribe the3.4. Analysis of adoption factors
The above-mentioned 3 case studies may suggest thedesign method for self-standing steel tubular walls withfollowing common features in the reasons of adoption of

the design guidelines for other structural types. With thethe self-standing steel tubular walls:

existing design method, the embedded length of piles is

・ Road retaining walls of high height in a narrow spacedetermined from the correlation between the ground and・ Construction adjacent to existing structures

the piles. Therefore, the larger the diameter is and the・ Along beside a road where stopping the traffic wasdifficulthigher the wall is, the longer the piles become. In addition,

・ Construction in a relatively short period of timerequired, anddetailed displacement investigation rather than by detailed

・ Use of the construction yard of adjacent road was
impossible or limited

members tend to possess enough stress allowance, and theWith the development of construction methods andCurrently researches into steel tubular retaining walls

construction machines represented typically by the Gyrowith high stiffness in the stiff ground have been conducted

Press Method, it has become possible to press-in piles

at a technical committee TC1 of IPA (Committee oneven in such difficult site conditions as described in thisApplication of Self-Retaining Tubular Pile Wall to Stiff

paper. Similar construction cases seem to be increasing in

Ground). Following this, it is thought to be necessary tonumber. It is expected that the same construction type will

carry out researches on application of the structure in thelikely be adopted in future in sites with narrow space andgeneral ground as well. It will also have to be clarified

under limited construction time.

how rational the current design method could be, how bighigh stiffness. The walls are currently designed following

it is often the case that the pile diameter is determined bystress investigation. This may lead to the fact that the pile
design tends to become too conservative.

the diameter and how high the wall should be.

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

5. Acknowledgements
This paper is a summary of an activity of a technicalcommittee TC1 of IPA (Committee on Application of
Self-Retaining Tubular Pile Wall to Stiff Ground).

The

authors appreciate the valuable advice provided by eachcommittee member and advisors.
6. References
Advanced

Construction Technology

Center.

2006.

Design manual of self-standing steel sheet pile walls,
2p, pp. 28~38.
International Press-in Association. 2017. Press inretaining structures: a handbook, pp. AD II-17~AD
II-26.
Japanese

GeotechnicalSocietyStandards.

2013.

Geotechnical and Geoenvironmental Investigation
Methods, pp. 310~311. (in Japanese)
Japan Road Association. 2012. Guideline of road works
and retaining walls.
Japan Road Association. 2017. Specifications for
Highway bridges, Parts II: Steel Design, and V:
Seismic Design.
The Ports and Harbours Association of Japan. 2007.
Technical standards and commentaries for port andharbour facilities in japan.
Public Interest Incorporated Association of Nationwide
Disaster Prevention. 2017. Design outline of disaster
restoration works.

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