Volume 5, Issue 4 December 2020

Serial Report

Development History of SILENT PILER (Part 2)
Masaaki Ono
Director, GIKEN LTD.

Environmental Considerations and IT Enabling
The model ECO100 (Photo 1) was marketed as a successor model of the SA Series in 2002.
Advanced environment-conscious technologies and information technologies wereintroduced to promote reducing the overall burden on the environment across themachine lifecycle as well as during construction.
Fig. 1 shows the names of the components of SILENT PILERTM for readers’ reference. In
terms of structure, the rails for the sliding parts, such as upward/downward motion androtation of the chuck, and front/backward motion and rotation of the leader mast wereincreased in length to reduce loads and prevent backlash. In terms of materials, special
alloy steel and high-tensile steel plates corresponding to loads and morphology were used
to save weight. Also, forged parts of more tenacious materials were used instead of castparts in the chuck and the like, where stress was concentrated, to take advantage of fiber
flows*. Thus longer life of the machine was realized. The gripping force of the clamp claws
was improved to obtain larger reaction force on this and later models (Fig. 2).

Photo 1. Model ECO100

・No claws sliding・claws sliding

・Grasp evenly

・Grasp unevenly
・Graspingshallowly

・Graspingdeeply to the mostbottom end
Model ECO 100

Fig.1. Names of the components of SILENT PILER

Model SA 100

Fig.2. Improvement of gripping force, marks of clamp claws

Fuel consumption of the power unit was reduced by 7% to 10% due to electronic control, and the tier-2 exhaust gas
regulations of the time, in and outside Japan, were met. The ECO mode was newly provided to reduce the engine speedof the power unit by about 20% compared to the power mode and reduce the rated output, having a lower noise level
than the regulatory standards. Consequently, the machine can be operated at low fuel consumption and a low noise level
while maintaining hydraulic force unless high-load/high-speed operation is required in the construction site. In terms ofIT, as for the hydraulic force and operation status of the machine, “GIKEN IT System” was introduced in which values fromthe press-in sensor and stroke sensor in the machine and operation information were collected in a controller of thepress-in piling machine and displayed in real time by the maintenance software through the mobile communication
network. This allows the operation status of the piler to be checked from a remote location with a PC and appropriate
advice to be provided to local operators on the site from the information center.
In 2007, the multi-model of press-in piling machine SCU-ECO400S (S Series) (Photo 2) with the function for hard groundconditions mounted as standard, was launched. A single unit of this model can perform press-in piling with augering, as
well as standard press-in and press-in piling with water jetting, by attaching and detaching the hose reels and standard
press-in attachment (Fig. 3).
For the S Series machines, the main body and pile auger were light-weighted and downsized compared to the dedicatedmachines applicable for hardground conditions, in order to be used as a general-purpose machine. To achieve its10

Volume 5, Issue 4 December 2020
maximum excavation efficiency despite the downsizing, a Chuck Lock function (Fig. 4) was newly equipped, in which alock-plate fixed on the chuck was held and fixed using the hydraulic cylinder mounted on the chuck frame. In addition, aLeader Mast Lock function was also equipped, in which the lock plate on the center pin of the slide frame was held andfixed using a hydraulic cylinder mounted on the side of the leader mast to secure the rotating part of the main body firmly
during augering. This is the structure that prevents the loss of force. This enabled reliable transmission of auger torquesupported by a solid reaction base, resulting in an improvement of the efficiency and accuracy of pile installation. Aroundthis time technologies for hardground conditions were being developed including auger head test equipment, and so on.
* “Fiber flows” are fibrous flows of metal structure formed when metal materials are forged; metal structure flows in therolling/forging direction. When fiber flows flow along the shape of a forged product, the impact value as well as thefatigue strength are higher than when they are discontinued.
Press-in piling assistedwith augering

Press-in piling assistedwith water jettingStandard press-in

Photo 2. Multi-model SCU-ECO400 (S Series)Press-in piling assisted with augeringpile augering

standard press-in piling

ChuckFrame

standardpress-inattachment

ChuckFig.3. Press-in attachment

Fig.4. Chuck Lock Function

Modularization design
Although the S Series was a single unit that is applicable to a wide range of conditions, further cost-down and higher
production efficiency were needed for the purpose of global business development. In 2011, the 25 models that had
been developed before were integrated into 5 types of base machines. The production efficiency was improved bymodularizing main components including the leader mast and saddle. This is the birth of the F Series (Photo 3). Startingwith the model F201 marketed overseas in 2013, the model F301 (Hat Piler), model F101 (U Piler for 400 mm wide sheetpiles), and the model F111 (versatile press-in piling machine for 400 mm wide sheet piles) were marketed by 2015. In
2016, 2 models, F401 and F501, which were applicable to a “Gyropress Method”, were announced.
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Model F101

Model F111

Model F201

Model F301

Model F501

Model F401

Photo 3. F Series machines
Approach to installation conditions and piles
The development of piling machines is directly linked to the development of press-in piling methods. There were various
barriers in construction sites other than ground conditions and each of them has been overcome. There are various typesof SILENT PILER (Photo 4): “Clear Piler” for the condition under the overhead restriction such as under bridge, “Zero Piler”
for zero clearance to adjacent structures such as buildings, “Concrete Piler” for concrete sheet piles, “Tubular Piler” forsteel tubular piles with interlock, and “GYRO PILER” that installs steel tubular piles directly in existing concrete structureswith rotary cutting to reinforce the structure. Technology is still evolving.

Clear Piler

Concrete Piler

Zero Piler

Tubular Piler

GYRO PILER

Photo 4. Types of SILENT PILER
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Latest model “SMART PILER”
The latest model, Smart Piler SX1 (Photo 5) was released in April 2020. This model
drastically improved the upward/downward motion speed and responsivity of thechuck. The highest press-in speed is 1.5 times higher than that of the model F101,
and 3 times higher than that of the model SA75. The responsivity was improved byeliminating time lag in switching the valve to reverse the upward/downward motionof the chuck; the penetration and extraction, that is, press-in at the highest speed andinstant shifting to extraction, can be repeated automatically at high speed. This
prevents plugging and forming a pressure bulb to realize the smart press-in pilingwork, in which piles are penetrated while keeping press-in force low. Moreover, thelightest body in the history (3,850 kg) * led to an improvement of the operating
efficiency.

Photo 5. SMART PILER SX1* Within machines for 400 mm wide U-shaped steel sheet pile

Development History of Gyropress MethodTM
Birth of Tubular Piler
One of many types of SILENT PILER is “Tubular Piler”, a press-in piling machine for steel tubular piles with interlock, which
are the piles suited to port construction works, flood and tidal surge protection in river basins, anti-seismic strengtheningof bridge pillars, bridge foundations, and so on.
Tubular Piler started to be developed in 1986. During the development, a different method to hold piles was needed forthe sheet piles and for the tubular piles. While the sheet piles are held by a clamp from outside to mobilize the fictional
force, the tubular piles are likely to buckle if they are excessively held from outside. Then the method adopted was toexpand a clamp part from inside the tubular pile, mobilizing the frictional forces between the clamp and the inner surfacesof the piles as shown in the Photo 6. Thus, Tubular Piler was completed and first used on a construction site in 1990. The
tubular piles are applicable to different design requirements by altering the pile diameter and thickness, which allowsefficient construction of many various structures for different purposes. However, it had a big issue of soil plugging at thepile toe. If piles are plugged, a higher press-in force is necessary and eventually piles cannot be penetrated. As thecountermeasures for this issue, water jetting was initially used to assist in pile installation. However, it was not possible
to install piles into stiff and hard ground in many cases, and then pile augering was used instead. The machine for hardground conditions was launched in 1997 and its use was expanded rapidly. Yet pile installation was frequently hinderedby very stiff base rock layers or existing concrete structures (Photo 7). To solve this problem, GYRO PILER started to bedeveloped.
BeforeAfter

Photo 7. Construction in Ibaraki Prefecturewith Tubular Piler for hard groundPhoto 6. Clamps of Tubular Piler
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Birth of “GYRO PILER”, steel tubular pile rotary press-in piling machine
The press-in piling machine presses in piles using static load, so it had a weakness toovercome in that it was difficult to install piles into hard ground. Mr. Kitamura, thedeveloper, had been wanting to solve this issue for years. After trying several ideas, in1982 he conducted a demonstration experiment of Prototype 1, which installed steel
tubular piles by rotating them into the ground. Subsequently in 1986, a demonstration
experiment of Prototype 2 was conducted, which was the model KGK-100H with thechuck changed into a rotary type. However, the rotary type was difficult withtechnologies and part performance of the time, so the development was stopped
once. Even so, it was essential to overcome the ultra-hard ground conditions toexpand the market of implant structures on the permanent construction. Then, fullscale development of the rotary press-in piling machine was started in 2002. At thesame time, it was decided that steel tubular piles with pile toe ring bits (Photo 8)
would be developed to press piles by rotating them into harder ground, providing theproposal to Nippon Steel Corporation, the major blast furnace steel manufacturer.

Photo 8. Tubular Piles withpile toe ring bits

“GYRO PILER”, which was unveiled at the New Technology Presentation (Ariake, Tokyo) in the fall of 2003, installs steel
tubular piles with pile toe ring bits by rotating them into the ground. It was first applied in a project in Hokkaido in 2004
(Photo 9). Because it was a reinforcement construction project of bridge pillars on the conglomerate ground withextrapolated SPT N-value of 1,500, it was considered difficult to install piles by the conventional piling methods. Theconstruction was successfully completed using GYRO PILER GRA1030 (Photo 10); thus the new construction method“Gyropress Method” (Fig. 5) was established.

Photo 9. First installation in Hokkaido

Photo 10. Model GRA1030

Fig. 5. Gyropress Method

Gyro Piler, which presses in piles penetrating through ultra-hard ground to build implant structures, was used increasingly
more as it became well-known. Especially after the Great East Japan Earthquake in 2011, it was used for embankment
improvement works implemented by National Government and restoration works in Tohoku district as the construction
method which rapidly builds the structures that firmly withstand earthquakes and tsunamis. This led to the construction
method being used widely at a rapid speed across Japan. Kitamura also encouraged development of GYRO PILER for large
diameter piles immediately after the Great East Japan Earthquake, and developed the ultra-large model GRV2540 (Photo11) which can rotary-press in steel tubular piles with 2,500 mm O.D. in the following year. It is capable of building theimplant structures that withstand massive tsunamis, being of an exceptional scale (body weight 105 tons, maximum
press-in force 4,000 kN, maximum rotation torque value 2,940 kN-m). Currently, there are various models including
machines for batter pile installation and machines for ultra-low overhead clearance, in addition to the 6 models applicablefor piles with 500 mm to 2,500 mm O.D.

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Photo 12. The test of concrete
structures with rotary press-in piling

Photo 11. Ultra-large model GRV2540

The use of Gyropress Method has grown rapidly in recent years and it became one of the representative implant methods.
Its notable feature, the main factor of the growth, is not only that the method is applicable for the ultra-hard ground, butthat it is not necessary to remove existing reinforced concrete structures by using customized steel tubular piles with anappropriate number of cutting bits set according to the pile diameter and hardness of the ground. It can build the firm
implant structure rapidly by pressing in piles through concrete structures, which is an inestimable advantage (Photo 12).
Combi-Gyro MethodTM
The Combi-Gyro Method (Fig. 6) (Photo 13) is a construction method of walls
having excellent functionality and economy, combining steel tubular piles withhigh rigidity and hat-shaped steel sheet piles with excellent water tightness,using one unit of press-in piling machine. It was developed jointly with theNippon Steel Corporation, applying the Gyropress Method. One of its features
is that it can build walls with the strength required in terms of design at low
cost, by optimizing the combination of the pitch, diameter, and thickness ofsteel tubular piles. The walls can be used widely such as earth retaining walls
and cutoff walls. This method is applicable for constructions of retaining walls
for highways, river revetments, sea embankments, anti-seismic strengthening,liquefaction countermeasures, and the like.

■Cross-Sectional Shape
Sheet Pile

Tubular Pile

Fig. 6. Combi-Gyro Method

With the Combi-Gyro Method, firstly, hat-shaped steel sheet piles are pressed in contiguously and secondly, steel tubularpiles are pressed in by rotating them using the steel sheet piles as a reaction force on the side of the steel sheet piles so
as to support the steel sheet piles. The dedicated machines for the Combi-Gyro Method have been developed, a single
unit of which can press in the hat-shaped steel sheet piles and steel tubular piles, by changing the chuck.

Photo 13. The construction site in Miyagi Prefecture with Combi-Gyro Method

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Skip Lock System
The Skip Lock system is the system of more efficient mono pile installation, that is installing steel tubular piles with aconstant spacing between piles. GYRO PILER with the originally developed “Skip Lock attachment” is used. Conventionallyfor mono pile installation by only GYRO PILER, dummy short piles needed to be pressed in between the permanent steel
tubular piles, because only some clamps were able to grip piles due to the space between piles and then sufficient
reaction force was not obtained (Fig. 7). However, the dummy piles needed to be removed finally, which resulted in
unnecessary construction cost and period. Then the Skip Lock attachment was developed to secure a reaction force
without dummy piles.
The attachment can be moved by a crane. Three attachments are fixed on the 3 installed mono piles and connected at
the connection parts on the front and back of the apparatuses. Each attachment has 2 holding holes for the clamp. The3 attachments make a bridge on the piles, which makes 6 holding holes for the clamp. During pile installation, allattachments and mono piles are unified by the hydraulic pressure, so it can secure a reaction force from 3 piles to fix themachine body firmly.
The Skip Lock system has been used mainly for constructing the disaster prevention infrastructure, such as foundation
piles for sea embankments and landslide prevention piles, since it was first used in tide embankment construction in
Fukui Prefecture in 2013. It was also used in the tide embankment reconstruction in Iwate Prefecture (Photo 14) that
suffered a great damage from the Great East Japan Earthquake. Lately, it was used for installing landslide prevention pilesin the construction site of the Kyushu Shinkansen in Nagasaki Prefecture (Photo 15) for the first time.

Skip Lock System

Conventional Method
Dummy short piles

Skip Lock attachment

Fig. 7. The difference of conventional Method and Skip Lock System

Photo 14 Construction in Iwate Prefecture

Photo 15 Construction in Nagasaki Prefecture(To be continued on Part3)
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