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PF2302 – CONSTRUCTION TECHNOLOGYSilent Piling – A Construction Solution
Presented to: Professor Chew Yit Lin, Michael
Presented by:
Carmen Soon Jia Wen U085407A Do Tra My U077770E Goh Kok Hong U086672J Lai Shi Qi Jocelyn U086715N Le Khanh Ly U077782Y Lee Pui Kheng U086702J Neo Jun Jie Jeremy U086664L Quah Chi Hsien Sylvester U086662M Tan Shin U086682E Wong Kuan Wei U086670L Wu Kailing U086692B
Date of submission : 3rd November 2009
Table of Contents
TABLE OF CONTENTS.............................................................................................................................................2
1. INTRODUCTION................................................................................................................................................3
1.1 BACKGROUND................................................................................................................................................31.2 SCOPE.............................................................................................................................................................31.3 PURPOSE........................................................................................................................................................41.4 METHODS OF INVESTIGATION........................................................................................................................4
2. CONVENTIONAL PILING...............................................................................................................................4
2.1 AN OVERVIEW OF PILING...............................................................................................................................42.2 LIMITATIONS OF CONVENTIONAL PILING......................................................................................................5
3. THE SILENT PILER..........................................................................................................................................9
3.1 AN OVERVIEW OF SILENT PILER...................................................................................................................93.2 THE DIFFERENT MODELS.............................................................................................................................153.3 APPLICATIONS OF SILENT PILER..................................................................................................................20
4. BENEFITS..........................................................................................................................................................22
4.1 IMPORTANCE OF NOISE REDUCTION............................................................................................................224.2 IMPORTANCE OF MINIMAL VIBRATION.......................................................................................................244.3 IMPORTANCE OF MINIMAL WORKING SPACE REQUIRED............................................................................284.4 IMPORTANCE OF HIGH WORK EFFICIENCY..................................................................................................314.5 IMPORTANCE OF ENVIRONMENTAL FRIENDLINESS......................................................................................32
5. LIMITATIONS..................................................................................................................................................35
5.1 HIGH COSTS OF SILENT PILER.....................................................................................................................355.2 INFLEXIBILITY OF SILENT PILER..................................................................................................................355.3 CURRENT MENTALITY OF CONTRACTORS...................................................................................................355.4 RACKING OF PILES.......................................................................................................................................36
6. CASE STUDY....................................................................................................................................................36
6.1 HODOGAYA BYPASS ROAD WIDENING, JAPAN...........................................................................................366.2 BATANGAS GENERAL CARGO BERTH CONSTRUCTION, PHILLIPINES..........................................................42
7. RECOMMENDATIONS...................................................................................................................................46
7.1 CIRCUMSTANCES WITH SITE CONSTRAINTS................................................................................................467.2 CIRCUMSTANCES WITH TIME CONSTRAINTS...............................................................................................477.3 CIRCUMSTANCES WITH HUMAN RESOURCE CONSTRAINTS.........................................................................477.4 CIRCUMSTANCES WITH SPECIAL SAFETY REQUIREMENTS..........................................................................477.5 CIRCUMSTANCES WITH DIFFICULTY IN THE REMOVAL OF EXISTING SUBSTRUCTURE...............................477.6 DECISION TREE............................................................................................................................................48
8. IMPROVEMENTS............................................................................................................................................49
8.1 FULLY AUTOMATED SILENT PILER..............................................................................................................498.2 INTERCHANGEABLE SILENT PILERS.............................................................................................................53
APPENDIX..................................................................................................................................................................58
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ANNEXES...................................................................................................................................................................61
ANNEX 1.................................................................................................................................................................61ANNEX 2.................................................................................................................................................................62
REFERENCES............................................................................................................................................................62
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1. INTRODUCTION
1.1 Background
Slender high-rise buildings take up most of today’s urban construction projects. To ensure
stability, a strong and deep foundation is necessary and piling is an important component in
its construction especially for tall and slender building. However, problems and constraints
arise when traditional methods are employed in urban sites. These problems include noise
and air pollution especially if the site is located near to residential or working areas. In
addition, working space and vibration from the piling works are a huge concern in the urban
setting.
1.2 Scope
This report focuses on the reduction of noise and vibration generated by piling, and solutions
for working with limited construction space.
1.3 Purpose
This report studies the benefits of the Silent Piler technology in reducing noise, vibration and
dust caused by piling. It also looks at how it can be used in the urban context to address the
issue of space constraint.
1.4 Methods of Investigation
A visit was made to a construction site to help us better understand noise generated on-site
situation. Thereafter, noise level measurements were taken from the various construction
processes and piling was found to be the greatest contributor of noise pollution. Secondary
research was done on piling and a recent technology called Silent Piler was decided upon. An
interview was conducted with the General Manager of Giken Seisakusho, a company that
produces and supplies Silent Pilers.
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2. CONVENTIONAL PILING
2.1 An overview of Piling
It is important to select the appropriate piling technology for a particular building, as it will affect the stability and strength of the foundation system.
Table 1: General Classification of Foundation Systems
In the above flow-chart, piles are being categorized into displacement and replacement piles.
Replacement piles are piles that require digging and removing of soil before the piles are
constructed. Displacement piles are inserted into the grounds by hammering or by using a vibro-
hammer.
2.2 Limitations of Conventional Piling
The conventional methods of piling face problems on numerous fronts. We have further
classified the problems into 3 main categories:
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General Classification of Foundation Systems
A p lh a P ileD e lta P ileG K N D riven P ileF ran k i P ileV ib ro con crete C o lu m n s
D riv e n C a s t-In -P la ce P ile s
W e st S h e ll P Ile
P recas t & C as tIn s itu C on c re te
G ro u t In je c t io n P IleR a ym o n d S te p T a p e r P ile
S tee l & C as tIn s itu C on c re te
P a rtia lly P re fo rm e d P ile s
H-PilesB ox P ilesTu b e P ilesS crew P ilesX -P iles
S tee l
Jo in ted P ilesP res tressed P ilesD a id o S S P iles
C on cre te
P re fo rm e d P ile s
Displacem ent
S m all D iam e te r P erc u ss ion P ile
P e rcu ss ion P iles Rotary PIles C on tin u ou s F lig h t A u g er/F lu s h P ile
B o re d P ile s C a ss io n s
Replacem ent
Deep Foundation System s S h a llow F ou n d a tion S ys tem s
Foundation System s
Vibrations Sound Space
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2.2.1 Vibrations1
In the construction of displacement piles, the piles are inserted into the ground by hammering or
utilizing a vibro-hammer. Both methods cause large propagation of sound waves to the vicinity of
the works, thus increases the probability of damage to the surroundings.
In the process of driving in a pile, there are three types of vibrations that are produced, namely:
Surface Wave (Rayleigh Wave)
Cylindrical Wave
Spherical Wave
With reference to figure 1, it is shown that
during the process of driving in the piles,
spherical waves are emitted from the pile toe
due to the dynamic resistance present, whilst
the cylindrical wave propagates laterally
from the pile shaft in contact with the
surrounding soil. Surface waves, also known
as Rayleigh waves, are created at a critical distance from the pile where the spherical waves
refract upon reaching the surface.
The modes of propagation of the vibrations are classified as follows:
Wave propagation in piles
Pile-Soil Interaction
Wave propagation in the ground
Dynamic soil-structure interaction
1 Rainer, K. (2008)
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Figure 1: Possible types of vibrations during piling process
Pile
According to Figure 2, at (1), the hammer
strikes the pile cap and pile head (2),
generating energy which is transmitted
through the pile (3). This would then
cause pile-soil interaction along the pile
shaft (4) and at the pile toe (5). Through
the lateral propagation of the vibrations in
the soil layers and groundwater, which
occurs at (C), it leads to the dynamic soil-
structure interaction.
The danger occurs when the frequency of the vibration corresponds to the natural frequency of the
soil since this will cause resonance and the resulting increased amplitude will cause differential
settlement in the soil and hence damage adjacent structures.
2.2.2 Sound
Noise is a major problem during the process of pilings. The impact caused by the striking of the
pile hammer onto the steel piles produces unacceptable audible levels of noise. Based on medical
research, the human hearing threshold is found to be approximately 120dB for a single exposure.
However, it has also been proven that prolonged exposure to noise levels of 85dB and above will
inflict noise induced injuries.
Based on Table 2 below, the level of noise produced is at least 170dBRMS for a wooden pile. This
is already beyond the tolerable threshold level of human hearing.
In Singapore, the Ministry of Manpower has identified the danger of Noise Induced Deafness
(NID) in various industries. The construction industry has seen a rapid increase from 17 cases to
33 cases in NID cases from 2007 to 20082.
2 Refer to annex 2 , Information and statistics 2008 (n.d.)
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Figure 2: Wave propagation incurred during piling process
Type of Pile Sound Level (dBpeak) Sound Level (dBRMS) Sound Level (dB SEL)
Wood piles:1 180 dBpeak 170 dBRMS 160 dB SEL
Concrete piles:2 192 dBpeak 176 dBRMS 174 dB SEL
Steel H-piles3: 190 dBpeak 175 dBRMS 155 dB SEL
12-inch steel piles: 208 dBpeak4 191 dBRMS5 175 dB SEL6
14-inch steel piles: 195 dBpeak @ 30m7 180 dBRMS @ 30m8
16-inch steel piles8: 200 dBpeak@ 9 m 187 dBRMS @ 9m
24-inch steel piles9: 212 dBpeak 189 dBRMS 181 dB SEL
30-inch steel piles10: 212 dBpeak 195 dBRMS 186 dB SEL
36-inch steel piles11: 214 dBpeak 201 dBRMS 186 dB SEL
60-inch dia. steel piles: 210 dBpeak 195 dBRMS 185 dB SEL
66-inch dia. steel piles12: 210 dBpeak 195 dBRMS
96-inch dia. steel piles12: 220 dBpeak 205 dBRMS 195 dB SEL
126-inch dia. steel piles12: 213 dBpeak @ 11m 202 dBRMS @ 11m
150-inch dia. steel piles13: 200 dBpeak @ 100m 185 dBRMS @ 100m
Table 2: Sound levels of different conventional piling method3
2.2.3 Space
The lack of space poses a huge problem at most construction sites. Since it is used for many
concurrently ongoing activities, which includes:
Material Storage On-site access for delivery circulation Machinery
In a typical piling operation, space is required for:
Piling Machine Piles Supporting Equipment Bored Pile Storage of excavated soil Bentonite tank
3 Noise reduction (2008)
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In a confined site especially, the size of the machines are very significant. For instance, a
conventional piling machine, occupies a large area; which is approximately 5500mm by 3500mm
and usually requires a height clearance of more than 10 meters, mainly due to the length of the
piles.
3. THE SILENT PILER
3.1 An Overview of Silent Piler
Achieving a balance between the Five Construction Principles (Environmental Protection, Safety,
Speed, Economy and Aesthetics) in piling work has historically proved difficult. Noise, vibration
and issues of sustainability have traditionally been at odds with speed and economy, which has
led to the imbalance. To address these fundamental problems, there has been the development of
Silent Piling Technologies derived from the “Press-In Principle”. Piling works can now be carried
out with minimum vibration and greatly reduced noise. Also, this technology has allowed piling
works to be carried out in circumstances where there are limited access conditions, overhead
obstructions and difficult geological conditions. The introduction of the silent piling technology
breaks the shackles of conventional construction methods.
3.1.1 Implant Structure
Sustainable construction can be achieved through the “Implant Structure” concept. Instead of a
wide spread footing, pre-formed modular components, termed “Implant Materials”, are pressed in
from ground level and integrated with the Earth to form the foundation and support the structure
above. This is done as a simple one-step procedure without temporary works or underground
work required for foundation. At the end of the life of a structure or due to a change in city
layouts, implant materials can be extracted and recycled, leaving a clear site for redevelopment. In
short, this simple procedure shortens the duration of piling works, reduces costs, and minimizes
environmental impact.
3.1.2 Press-In Principle
Conventionally, prefabricated piles are pounded or vibrated into the ground. These methods
inevitably generate excessive noise and vibration due to their reliance on percussive or vibratory
energy. The Silent Piler makes use of the “Press-In Method”, based on the Press-In Principle, for
environmentally friendly and sustainable pile installation. The illustration below outlines the basis
of the Press-In Principle.
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3.1.3 Press-In System
3.1.3.1 Standard Machine Layout
Under normal working conditions, the Silent Piler can operate with just one crane to pitch piles.
When the pile being pressed in is sufficiently stable, the Silent Piler releases its clamps from the
reaction piles and uses this pile to raise itself and move forward. This self-moving system
eliminated the need for support by a crane as in normal piling operations. In other words, even
where a site requires a large jib radius for pitching, a relatively light-weight crane can be used.
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Figure 3: Press-in Principle
3.1.3.2 Initial Press-In
Where there are no piles in the ground from which to start, the Silent Piler is set up on a reaction
stand. An appropriate amount of counter-weight, determined by the ground conditions and length
of piles, is placed on the reaction stand. The first pile is then pressed in, deriving reaction force
from this combined weight. As each of the initial piles is installed to the specified depth, the
Silent Piler moves forward and clamps onto that pile, thus increasing the available reaction force.
The initial press in phase is completed when all the initial piles have been installed and the Silent
Piler has moved off the reaction stand onto these piles.
3.1.3.3 Curve and Corner Installation
The Silent Piler can construct curves or other complicated configurations with ease. The
minimum radius of the curve varies according to the pile specifications and Silent Piler model.
The Corner Four (C4) function allows the Silent Piler to install up to 2 piles at right angles to and
on each side of the proposed corner position. Once a sufficient number of reaction piles are
installed, a service crane simply lifts the Silent Piler off the initial line onto the new line.
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Figure 4: Curve and Corner Installation
Figure 5: Standard Operations of Press-in Mechanism
3.1.3.4 Press-In Quality Control System
Using the Press-In Quality Control System, any valuable information for piling management, such
as pressed-in force, skin friction, toe resistance, penetration depth and performance time, is
available from an on-board computer in real time. All measurements are useful to recognize
abnormal factors underground and certify the quality of the completed structure. In other words,
load tests which are normally carried out after piling is completed, are being executed during pile
installation without extra equipment.
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3.1.3.5 Automatic Press-In Operation System
In the Press-In Method, use of the down-stroke/up-stroke procedure is the essential way of Press-
In Operation. By the Automatic Press-In Operation System, an operator inputs the best variables
of press-in force, press-in stroke and extraction-stroke to the Silent Piler. The system enables the
machine to maintain the most efficient press-in performance. Press-in piling work has been
shifted from a physically-trained experienced field to a logically-progressed scientific field. The
difference between manual operation and automatic operation is illustrated in the diagram below.
Figure 6: A comparison between Manual Operation and Automatic Operation
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3.1.3.6 Standard Operation of System
Figure 7: Standard Operation of GRB system
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3.1.4 One-Step Approach
The One-Step Approach is a concept that seeks to eliminate the temporary works required in the
construction of conventional footing structures. Utilizing the concepts described earlier, Implant
Materials are installed directly into the Earth, where they are capable of performing as foundation
and structural elements. No temporary works are required and this reduces time and cost to build
the foundation. Also, there is minimal disturbance to the ground and work can be undertaken in
confined areas. The result is that the construction process minimizes the environmental impact to
our world.
3.1.5 Typical Forms of Implant Structure and their Application
Implant structures constructed by the One-Step Approach can be categorized into three types –
Implant Wall, Implant Shaft and Versatile Foundation.
The Implant Wall is a high quality cantilever retaining wall constructed by environmentally
friendly press-in piling without the need for temporary works. It fully satisfies the Five
Construction Principles even under adverse conditions and site restrictions such as limited access,
overhead obstructions and geological difficulties.
The Implant Shaft is a closed form of the Implant Wall. It is particularly useful for reinforcing
bridge piers. Fully automated underground car park (“Eco-Park”) and bicycle parking (“Eco-
Cycle”) systems have been developed, utilizing the excavated space inside the Implant Shaft and
the Implant Wall as the outer structural element. When the Implant Shaft is used as a foundation,
the captured space inside which is used for different purposes, it is known as the Versatile
Foundation.
3.2 The Different Models
3.2.1 Gyro Piler
The more developed the urban areas are, the higher the demand to review and strengthen public
facilities and infrastructure. Especially in congested urban areas, it is becoming very troublesome
to rebuild a new structure after complete removal of the existing substructure. The Gyropress
Method has been developed as a new technology based on the Five Construction Principles to
solve such a problem without affecting the environment and neighbouring societies. With this
method, a pile is installed by the “Press-In + Gyration” system. It is no longer necessary to
remove existing underground structures before implant structures are constructed.
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As an addition to the Press-In Principle, the Gyropress System uses gyration to assist pile
installation. Clamped on three completed piles, the Gyro Piler grips a tubular pile and applies both
vertical and gyratory forces to the pile. The tubular pile has “Gyropress coring bits” fixed to the
pile toe. These cut an annular pathway into the ground and retaining the vertical motion of the
normal pressing-in. The gyration helps to cut friction on the inner and outer surfaces of the pile.
This method of installation allows piles to be installed into much harder ground or through
obstructions, theoretically, without the need to remove internal soil. The Gyropress System paves
the way to allow the installation of new foundations through existing underground structures
without the need to remove them first. As with other silent piling technologies, this system
supports sustainable development and further enables the realization of the implant structure
construction.
Figure 8: Standard Machine Layout of GRB System
Figure 9: Standard Operation of Gyropress System
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Gyropress Method can be applied to any type of construction work, such as road, railway, river,
bridge and harbour. Moreover, the Gyro Piler can install piles at a lateral angle to both the right
and left sides so that it is possible to install strut piles from the same position to construct a high
strength structure with minimal land space.
Figure 10: Application for Road Widening Project
3.2.2 Water Jetting System
3.2.2.1 Problems
During pressing-in of a sheet pile, a pressure bulb is created at the toe of the pile, the pile shape
and the interlock may fill with soil and as the pile is pressed deeper, the reaction due to these
effects becomes enormous. The increase in resistance requires greater pressing-in force leading to
deformation of the pile and loss of productivity.
3.2.2.2 Solutions
High-pressure water jetting reduces the pressure bulb by temporarily and locally loosening
granular soils and softening cohesive soils. Simultaneously, the returning water lubricates the pile
surface and the interior of the interlock, reducing friction and the tendency of the pile to plug.
Accordingly, productivity can be maintained without damage to the pile.
3.2.2.3 Advantages
As the volume and pressure of water can be adjusted according to the requirements, and as the
water is applied only where it is needed, large voids are not created. The soil perimeters quickly
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return to their normal state, which is evident by the adequate reaction force available in pressing-
in the following piles. In short, by controlling the water-jetting procedure, all the advantages are
realized without damage to the soil. Water-jetting is effective by utilizing the high-pressure
flexible hose supplied from a reel system (Super Jet Reel, Piler Jet Reel) atop the Silent Piler. The
hose is attached to the inner face of the sheet pile by a jet lock.
Figure 11: Piler Jet System
3.2.3 Eco Jet System
With a highly-automated operation of the integrated Eco Jet System, water flow is controlled for
jetting in accordance to the press-in movement of the Eco Piler. Thus, the system can save labour
and water usage. Moreover, the whole operation is carried out by one power source (engine unit)
in the most economical and ecological mode.
3.2.4 Super Crush System
3.2.4.1 Problems
In certain ground conditions, cobbles and stones may be present, creating very difficult piling
conditions. However, use of conventional augering machines or heavy equipment for the cast in-
situ diaphragm wall may risk collapse or over-turning of the machines as well as the necessity of
temporary staging or an access road.
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3.2.4.2 Solution
The Silent Piler is equipped with an integral pile auger to enable the Press-In Method to be used
in hard ground where Water-Jetting would not be effective. Gripping the auger casing along with
a pile, hard soil just below the current pile toe location is loosened by augering. The pressing-in
action is carried out while simultaneously extracting the auger, the pile penetrates hard soil as it
collapses around the augered areas.
3.2.4.3 Advantages
Use of the integral augering based on the Press-In Principle, enables all the advantages of the
Press-In Method to be adopted to pile installation in difficult subsoil conditions. Therefore, there
is no danger of over-turning of the machines, or necessity of wide right of way or temporary
staging. Moreover, the Super Crush System achieves minimum disturbance to the surrounding
subsoil with limited spoil generation. Thus the associated environmental impact is minimal during
the entire piling operation.
Figure 12: Super Crush System
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Figure 13: Integral Augering Procedure
3.3 Applications of Silent Piler
Similar to other conventional piling machineries, the silent piler does not have constraints on the
type of terrain applicable. In different ground conditions, there are options of different kinds of
silent piler, which includes the solo piler, water jetting system, and super crush system. The solo
piler is being used for normal ground conditions.
Water jetting systems are usually used for hydro demolition as well as retrofitting works in
construction. Here in the piler jet system, water jets are used to aid in the piling process to ease
the pressure bulb in the grounds that are created during the process of pressing in. The water jet
helps to relief the resistance caused and prevents the deformation of the piles. Below shown are
some examples of how the water jetting are placed in the piles and integrated with the silent piler
to provide for a more efficient piling technology.
Figure 14: Water Jetting System (Jet Piler System)
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Figure 15: Nozzle Layout4
The water jetting system helps to reduce friction in soil by lubricating as well as loosening the
granular soil and soften the local cohesive soil temporary to reduce the toe friction. Moreover, it
does not have any lasting effect on the soil strength and do not create large void in the soil.
In hard piling situations where cobbles and stones were present, the conventional methods will be
the option of using augering machines and heavy machineries for the piling process. The present
super crush system is an auger integrated in the piler, which is a single machine that can auger
and pile at the same time. It not only increases efficiency, it also produces lesser noise and
vibration as well as ensuring a higher level of safety. Illustrated below are some pictures showing
the super crush system.
Figure 16: Super Crush System
4 Giken (n.d.)
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Figure 17: Augering Dimension5
This system is able to pile with minimum soil disturbance and removal. Hence, the super crush
system is able to bring the environmental impact of the piling process to the minimum.
Catering to the different needs in the piling process, there are numerous types of piles in the
industry. In spite of the fact that the silent pilers are specifically designed for unique types of
piles, there are several types of sheet piles that are applicable to the silent pilers. In addition, it is
accessible to small, confined sites where convention piling machineries are unable to access. This
is due to their small body size in comparable to the amount of load they are able to press in.
Moreover, contrasting to convention piling machines, they make use of the previously piled piles
as their platforms to work on instead of an area on ground or a temporary platform to be
constructed. In terms of speed, it is also on competitive grounds on the convention piling
machines. However, in contrast to percussion methods, each silent piler can only be applicable to
a specific size and shape of piles. Despite so, there are numerous types of sheet piles applicable,
for example, the U- shape pile, H-shape pile, as well as concrete piles.
4. BENEFITS
4.1 Importance of Noise Reduction
The distinct benefit of the ‘Silent Piler’ is that, it produces the least amount of noise relative to
other conventional pilling machineries. The table below displays the range of noise level
generated by individual noise sources from both our daily lives and the various construction piling
techniques.
5 n.d. http://www.agd-equipment.co.uk/pdfs/machines/125.pdf
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Figure 18: Graph of Noise level against the Distance from piling operation
As illustrated clearly in table 3, a huge portion of the noise generated was found to be emitted
from the “Power Pack” component of the silent piler. The results reflected noise level
measurements at 75 dB taken at a radius of one meter from the source. This happens to be slightly
higher than a conversational speech (60-70 db) and relatively similar to the noise level of street
traffic (70-80 dB). Therefore, the introduction of silent piling technology can effectively reduce
the noise level up to a maximum of 60 dB in comparison with other conventional piling
techniques.
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Table 3: Differences in noise level between conventional piling machinery and silent piler
150
Singapore Standards
According to Singapore Standards, the permissible construction noise limits for worksites within
150 meters from existing residential premises range from 50 dB to 90 dB. This is also dependent
on the types of affected building and the construction time periods (Please refer to Annex 1 for
more details). As shown in Figure 18, with the radius of 150 meters, the power pack could
generate a noise level far below 30 dB, which is equivalent to the noise level experienced in a
library (refer to the table 3).
Hence, after analyzing both the table and the figure, this report foresees that the silent piler can
bring about the best solution to reduce the unwelcome noise induced during piling operations as
compared to the other conventional piling approaches. More importantly, the silent piler
eliminates the ‘impact’ sound found in conventional piling which allows it to produce minimal
noise. With the press-in technology, the noise disturbance to the surroundings can be reduced
dramatically. In addition, it also creates an environment free of noise hazards to protect the
construction workers.
4.2 Importance of Minimal Vibration
Conventional dynamic piling methods, such as impact hammer or vibro hammer, have shown
from past experiments to be typically producing large vibrations. Hence, their usages are often
precluded from vibration sensitive areas such as the densely populated urban areas or laboratories,
hospitals and libraries. This is further illustrated in the three figures below (figure 19, 20 & 21).
Figure 19 and 20 show the maximum acceptable vibration to prevent structural damages and
disturbance to the people from disturbance and structural damages in compliance with Eurocode
3. Based on the same scale, ground vibration levels of the impact hammer and vibro-hammer
were measured and plotted at different distances during the piling operation. The vibration levels
were all quantified in peak particle velocity (ppv) which is the velocity of disturbing passing wave
incurred in ground particles during vibration.
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Figure19: Eurocode 3: maximum acceptable vibrations to prevent human disturbance
Figure 20 Eurocode 3: Maximum acceptable vibrations to avoid structural damage
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Figure 21:
Measures ground vibrations during dynamic piling (data from Head & Jardine, 1992)
Though the information is only reflected on Eurocode, it can be inferred that cautious
consideration should be taken for the usage of impact hammer or vibro hammer in areas sensitive
to vibration which can be applicable to Singapore as well.
Distinct from conventional dynamic piling methods, the silent piler offers a vibration-free piling
operation in today’s construction industry. Different experiments have been conducted to prove
this advantage of the silent piling.
Figure 22: Measured vibrations at sites 1 and site 2
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It can be clearly seen from Figure 22 (for further details of this experiment, please refer to the
Annex) that by applying the press-in piling method, ground vibrations can be reduced by 10 – 50
times compared to other usual piling methods such as diesel hammer or vibro-hammer. In
addition, unlike conventional piling methods, the vibration produced by press-in method compiles
with the maximum acceptable vibrations (as shown in Figures 20 and 21), it is not the same case
to both conventional piling methods.
Piling operation can cause ground borne vibration which is a serious concern for the
surroundings. Not only does it cause destructive damages to adjacent structures, it is also an
environmental nuisance for people living nearby. The ground borne vibration arising from various
piling method was predicted and induced which is demonstrated in Figure 21.
Figure 23: Prediction of ground borne vibrations arising from various piling methods
From Figure 23, the prediction curves of the press-in method are all in compliance with the
maximum acceptable vibrations shown in Figures 20 and 21.
Hence, it is evident that the silent piler utilising the press-in piling method can offer a desirable
alternative for piling installation in areas where vibration impact is the foremost concern. Also,
the silent piler promotes an environment without vibration disturbance to human and surrounding
structures, which is one of the critical goals of any construction project.
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4.3 Importance of Minimal Working Space Required
The usage of conventional piling machineries requires the setting up of bulky machineries. This
poses as another challenge to Singapore’s urban landscape as a huge construction corridor is
needed and the system is dependent on a flat working ground to place their machines. Frequently,
the entire set up of these huge machineries occupies a tremendous amount of space and this can
affect the existing traffic flow drastically or cause inconvenience to the public
Table 5 below shows a list of pile drivers which are commonly used for sheet piling in Singapore.
It is observed that the working space required by silent piler appeared to be the smallest relative to
the rest. Thus, with this advantage, silent piler would be able to deal with the tight working space
constraints faced in the urban landscape and solve those almost impossible tasks if conventional
approaches were used instead.
Type of Pile DriversWorking Dimension
(Length x Width x Height)
Weight
(tonnes)
Hydraulic Diesel Hammer6 12.0 x 3.6 x 26.0 45.0
Rotary Piling Rig2 10.5 x 4.3 x 20.6 65.0
Mobile crane with Vibro Hammer 13.0 x 2.8 x 3.1 40.4
Silent Piler3 2.4 x 1.2 x 2.6 9.4
61http://www.alibaba.com/product-gs/237155274/
piling_machine_hydraulic_static_pile_driver_construction_machinery.html2http://www.ecplaza.net/product/179049_943575/rotary_piling_rig.html3http://www.arcelorprojects.com/EN/driving_equipment/ZP100.htm
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4.3.1 Lateral Working Space
Urbanization in Singapore has advanced rapidly leaving future infrastructure and pockets of land
undeveloped. These working space constraint areas include the narrow streets between existing
buildings and edges of the slopes, are not able to be developed due to the inaccessibility of the
bulky machineries onto the working sites. However, silent piler has been designed to cope and
work within these tight working constraints shown in Figures 24 and 25, maximizing the
development of these peripheral lands without causing wastage.
Moreover, the cost for land in Singapore is extremely high due to its land scarcity. Hence, it is
important to maximize the usage of land and prevent the creation of dead space. For example,
retaining wall has to be installed right up to the edges. It would be almost impossible to use the
conventional approach. With the introduction of the silent piler, retaining wall can now be
installed adjacent to existing structures shown in Figure 26. As a result, more underground
space can be used for development illustrated in Figure 27.
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Table 5: Working Dimension of different piling machineries
Figures 24 and 25: Tight working space (Giken Seisakusho International, 2005)
4.3.2 Vertical Working Space
Height issues come into concern when there are overhead restrictions such as under existing
structures, bridges or high tension cables. As shown in Figure 28, the press-in technique allows
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Figure 26: Retaining walls built adjacent to the boundaries (Giken Seisakusho International, 2005)
SIDE VIEW
PLAN VIEW
Figure 27: Increased land space for underground development (Giken Seisakusho International, 2007)
for piling works to be carried out smoothly. This is simply because the press-in point is located
close to ground level. Without this press-in piling technique, it would be tedious and almost
impossible to complete such work tasks.
4.4 Importance of High Work Efficiency
4.4.1 One-step Approach
The “one-step approach” that is seen in silent piling aims to reduce the number of procedures in
the construction process which subsequently turn them into a single sequence of events. Through
this approach, not only will that allows construction works to proceed in a narrow construction
corridor without affecting the nearby structures or services, it also eliminates temporary works
required during the process. Hence, there will be minimum or no disruption to the daily activities
of the public near the site area. The elimination of the temporary works can also save time and
cost for the project.
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Figures 28 and 29: Pile installation under overhead structures (Giken Seisakusho International, 2007)
In Table 6 shown above, it compares the “one-step approach” with other conventional piling
techniques for a typical road widening project. It is observed that the three alternative piling
techniques were rather unfeasible as they are either too uneconomical or inconvenient to be utilized.
4.4.2 Operation
The silent piler is also known as a semi-automatic unified piling system. Apart from setting up the
reaction stand for the initial press-in of the first few piles, the silent piler can start self-moving to
the other piles using reaction forces instead of relying on the reaction stand. There is also the
Giken Reaction Base (GRB) System that allows all equipment to be supplied and operated from
the top of the pile wall without the need for external staging. The self-moving technique and GRB
System allow the machines to operate in the absence of temporary staging works. Most of the
operation is handled by the silent piler operator who uses the radio control transmitter. Moreover,
the noise and vibration generated by the silent piler is so minimal that it can still carry out
working process even during night time. This advantage enables the silent piler to have little or no
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Description “One-step Approach” using press-in piling technology
Hammered or vibrated pile wall
Bored pile retaining wall
Reinforced concrete footing
Temporary works None Requires pile guides and working platform to provide stable base for piling rig
Requires working platform to provide stable base for piling rig. Bentonite plant, if necessary.
Excavation of existing road to allow installation of footing
Right of way Closures
None Road Closure Road Closure Road Closure
Construction Delivery of piles to Delivery of piles to Delivery of piles, Delivery of piles,
traffic only end of wall installed position concrete, removal of spoil material at installed position
concrete, removal of fill
Noise Minimal Unacceptable Low Low Vibration Minimal Unacceptable Low Low Energy Consumption
Low High Very High Very High
Table 6: Comparisons between the piling methods for a typical road widening project
restriction on its operation time. As a result, the overall cost and time spent on a project can be
significantly reduced due to the factors discussed.
4.5 Importance of Environmental Friendliness
4.5.1 Engine Type
The Silent piler engines are considered the most environmentally friendly, amongst other
conventional piling machineries. The new generation engines of silent pilers are manufactured by
the Cummins Inc.; such as the Power Unit (EU300G3) displayed in Figure 30.
In Singapore, the criteria to import off-road diesel engines have to comply with the standard for
exhaust emission specified in the European Union Emission Regulations for Off-road Diesel
Engines - Stage I shown in Table 7. The European Union Emission Regulations is divided into 3
progressive stages. Stage I being the least environmentally friendly amongst the 3 and stage III in
Table 8 being the most environmentally friendly. In general, The European Union Emission
Regulations are measures implemented against the emission of gaseous and particulate pollutants
derived from internal combustion engines to be installed in non-road mobile machinery. The
advanced diesel engines for the silent piler were able to comply with the higher standards of Stage
IIIA in the same regulations. They also conform to the Environmental Protection Agency (EPA)
and California Air Resources Board (CARB) Tier 3 standards too.
By regulating the amount of hydrocarbons, particulate matter, nitrogen oxides, carbon monoxide,
and carbon dioxide emitted in accordance to these standards, the overall contribution towards
environmental damages
such as the acidification and global
warming can be reduced.
Furthermore, the in-
cylinder technology that
Cummins Inc. offers enables the
engines to provide a more
responsive power delivery and
achieve a major reduction in
noise with minimal maintenance requirements.
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Figure 30: Power Unit (EU300G3)
Stage I
Table 7: Emission standards for non-road diesel engines
Stage IIIA Standards for Non road Engines
Table 8:
Standards for non-road diesel engines
4.5.2 Oil and grease
Various additives are often used in lubricating oil and grease to improve their quality. However,
these additives might have a negative effect on the environment as some of them contain
hazardous materials even when used in small amounts. In addition, chlorinated additives may
cause the generation of dioxins during energy recovery of waste oil and incineration. However,
Giken has worked with one of the leading Japanese oil companies to co-develop a biodegradable
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Cat. Net Power CO HC NOx PM
kW g/kWh
A 130 ≤ P ≤ 560 5.0 1.3 9.2 0.54
B 75 ≤ P < 130 5.0 1.3 9.2 0.70
C 37 ≤ P < 75 6.5 1.3 9.2 0.85
Cat. Net Power CO NOx+HC PM
kW g/kWh
H 130 ≤ P ≤ 560 3.5 4.0 0.2
I 75 ≤ P < 130 5.0 4.0 0.3
J 37 ≤ P < 75 5.0 4.7 0.4
K 19 ≤ P < 37 5.5 7.5 0.6
hydraulic oil and grease called the Piler ECO Oil and Piler ECO Grease. The Piler ECO Oil and
Grease are made mainly from a fatty acid of vegetable oil. The vegetable oil has an advantage as
its resources that can be reproduced. In addition, the vegetable oil incorporates advantageous
characteristics such as good lubricating ability and high viscosity index. The Piler ECO Oil and
Grease not only exhibit itself as a good lubricant but also possess a long operating life. These
products have passed both the biochemical oxygen demand test and rapid toxicity test. They are
also certified "Eco Mark" by the Japan Environment Association as an Environmentally-friendly
Product, certifying that they are of high biodegradability which means that it discharges few
harmful substances into the environment as illustrated in Figure 31. This means that the silent
piler to work in waters, without having to worry about oil leakage from the engine.
Figure 31: Certified Eco Mark label
4.5.3 Paint
Studies have shown that toluene and lead based pigment will affect the human health
significantly. Giken chooses to use the environmentally-friendly paint, which is free from toluene
and lead based pigment for all its products so as to reduce the overall environmental impact.
Therefore, considering the factors mentioned above, it is seen clearly that the silent piler is a
wiser choice to be chosen over other conventional piling technique. It is able to protect the
environment for the benefit of the future generations as well as accomplishing its primary task to
paint in a clean and hygienic manner.
5. LIMITATIONS
5.1 High Costs of Silent Piler
Despite having so many significant advantages to the construction industry, the silent piler is
still under consideration for its usage in Singapore. One of the reasons is the cost. The cost of
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purchasing a ‘Silent Piler’ is much more expensive compared to other conventional piling
machineries. For instance, the price of a used silent piler ranges from ￥ 5,000,000
(equivalent to S$76,521) to ￥30,000,000 (around S$458,983). This is much more costly than
a normal piling machine such as a Piling rig machine which only cost S$48, 000. (The price
quotations above are quoted from an online selling website www.Alibaba.com )
5.2 Inflexibility of Silent Piler
One of the limitations of a silent piler is its inability to install only a particular shape of sheet
pile for each of its existing pile model. For example, a specific silent piler model used to
install the U-shaped sheet piles cannot be used subsequently for the installation of the H-
shaped piles. Therefore, it is concluded that the silent piler is not flexible enough to cater to
the needs of different construction projects. Thus, instead of merely purchasing one silent
piler model applicable for all construction projects, the piling contractors have to purchase a
series of different piler models, which in turn poses an additional financial burden on them.
5.3 Current Mentality of Contractors
In Singapore, silent piling is considered as a relatively ‘new’ technology due to the poor
exposure of this technology in the local market. Being a ‘new’ technology, it would be an
arduous task to change the mentality of a contractor in a relatively short period of time as they
lack the knowledge and technical expertise in the field of silent piling. A huge initial
investment would be required by the contractors to purchase new machineries for the
implementation of a ‘new’ technology. Many a time, this investment is so huge that it exceeds
that of the conventional approaches by 10%-30%. Furthermore, additional funds are required
to train site personnel to familiarize and operate the silent piler. Therefore, not all contractors
are willing or able to fork out this extra sum of money to purchase a ‘new’ technology if they
are able to rely on the conventional techniques to carry out the same task at a lower cost.
5.4 Racking of Piles
Another limitation encountered is the racking of the piles caused by the constant usage of high
press-in force. As a result of the racking, piles may go out of verticality - in both planes. This
happens when the piles are pressed into the hard ground and a tremendous level of strain is
exerted on the piles. The piles will either go out of its alignment or deform at the tip.
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Furthermore, this constant ‘press-in’ force is not as effective as chiselling in unexpected hard
ground or through obstruction. This makes the press-in technique inefficient and ineffective
when it meets the hard strata layer in the soil. Thus there is a need to enhance this process for
it to be comparable or better than conventional approaches.
6. CASE STUDY
6.1 Hodogaya Bypass Road Widening, Japan
6.1.1 Background
Hodogaya Bypass, on the National Road Route 16 in Yokohama near the port of Tokyo, requires
road widening from 6 lanes to 8 lanes. Clients for the project were Yokohama National Road
Construction Office, Kanto Regional Construction Bureau, and the Ministry of Land
Infrastructure and Transport. The one year project costs US$20 million and this includes the five
month piling contract that was worth US$3.5 million.
Figure 32: 6- lane road structure Figure 33: 8-lane road structure
The rationale of the Hodogaya Bypass road widening project was to improve the road
infrastructure in Japan, in the event of the then upcoming 2002 FIFA World Cup. A ground
investigation done in the area identified four main ground layers: a 7 metre to 8 metre thick layer
of fill, with concrete and rock fragments in the top 0.5meter; 2meter to 3meter of soft loam;
5meter of hard clay; a combination of hard clay and mudstone below 13meter. This project faces
constraints on numerous fronts, including noise and vibration, space, safety and time.
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Figure 34: Ground investigation data
6.1.2 Projects concerns
The Hodogaya bypass faces the problem of space constraint. It has a heavy traffic of
approximately 130,000 vehicles daily. The high traffic volume meant that it was important for the
traffic flow not to be disrupted during the construction process. Furthermore, the heavy traffic
could not be diverted due to the fact that the project is pressed to meet the designated dateline of
the World Cup and the tight time frame did not give the authorities ample time to construct an
alternative route. The site was confined to a steep slope that is long and narrow. Equipment and
materials required for the construction work were not allowed onto the highway.
Residential areas are located directly behind the construction site and the close proximity meant
that the piling method chosen, has to be of minimal noise and vibration.
It was important for the choice of construction method to be space efficient as the authorities did
not want to compromise the safety of the general public with the likely occurrence of traffic
accidents, due to objects falling from the construction site.
6.1.3 Piling Methods considered
Contiguous bored pile wall of 1m diameter piles
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Chicago caisson wall consisting of 2m diameter steel tube piles installed every 3m
separated by concrete lagging
500mm square prestressed concrete pile wall
Pressed-in steel tubular sheet pile wall of 900mm diameter, 12mm thick piles from
Japanese piling equipment manufacturer Giken
Piling Method selected:
Figure 35: Silent Piling in road widening works
The GRB non-staging piling system was adopted for this piling project. Two permanent
cantilevered retaining walls were constructed within the existing sloped embankments. They were
subsequently removed to form a 40m wide cut for road improvements.
A total of 376 piles were installed during the Hodogaya project to depths between 12m and 20m.
Piles were made up of two sections, welded together on site. Once each wall was completed, the
tubular piler and clamp crane will make their way back, removing the track way. The
embankment slopes were then excavated; leaving the newly constructed wall to retain the new cut
and at the same time act as a cantilever structure of typical retained height of 5m.
6.1.4 Reasons for choosing the piling method
Engineer Dainichi Consultant assessed four installation methods for the retaining walls based on
five factors: speed of installation, economy, safety, environmental impact and aesthetics.
The Giken Reaction Base (GRB) non-staging system was found to be the most efficient method in
this context. Unlike the conventional approach, it does not require temporary decking as a
working platform. The GRB non-staging system uses the top of piles as the working platform,
allowing piling to work in a tight and confined space which can never be achieved in the case of
conventional methods making it time and cost efficient. Moreover, since temporary platform is
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not needed, the construction site is neater and more organised, making it relatively more
aesthetically pleasing.
As the piler only moved along the constructed retaining wall, works would not have spilled into
the adjacent highway. Thus, the road would still be functional. Road users need not worry about
anaesthetic road diversions.
The machine deployed is the Super Crush Tubular Piler, which produces minimal noise and
vibration disruption. This is important for the residents, who are housed on the very same slope as
the construction works.
Finally, the GRB non-staging system is the most environmentally friendly construction
technology in this context. (Refer to the environmental benefits)
6.1.5 Problems of conventional piling
6.1.5.1 Conventional Vibro-Hammer
Figure 36: Comparisons between conventional vibro-hammer and Silent Piler
The conventional vibro-hammer requires a working platform, requiring more time and cost. The
working platform also occupies extra space in addition to the restricted space. However, the
utilization of the silent piling system allows works to be carried out by optimizing the space
available.
6.1.5.2 Contiguous bored pile wall
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Figure 37: Contiguous bored pile wall
This method was not utilized for this project, mainly because temporary staging is required.
Setting up those elements would require a lot of manpower and inevitably cause the project to
incur a higher cost. Temporary staging poses an additional problem as it will also take up more
space in the limited site.
Chicago caisson wall consisting of 2m diameter steel tube piles installed every 3m separated by
concrete lagging
Figure 38: Chicago caisson wall
The Chicago Caisson was not deployed for this project due to the lengthy construction time as a
dewatering system and temporary staging is required. Construction cost and duration would
increase due to the setting up of the abovementioned elements, requiring more machinery and
manpower. Temporary staging poses an additional problem as it will also take up more space in
the limited site.
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6.1.5.3 500mm square prestressed concrete pile wall
In this method, a wall formed consisting of 500mm square pre-stressed concrete piles. These piles
are augered through the centre and placed next to each other.
Figure 39: Prestressed concrete pile wall
Due to the need of a temporary staging, this method is not ideal for the construction. A temporary
staging would require large number of manpower, thus leading to higher cost and longer duration.
More importantly, temporary staging adds on to the space constraints present on the site. In
addition, this method requires site provision for a storage area for the large pre-stressed element.
Factors to
consider
Conventional Approach GRB System
Noise and
Vibration
Causes lots of noise and vibration,
at the impact point, between the
hammer and the retaining wall
pile.
Causes lesser noise and vibration, GRB System
uses a press in method, whereby the pile is
pressed into the soil, rather than the conventional
approach of hammering
Temporary
platform
Requires temporary platform Does not require temporary platform, thus this
saves space, time and money
Labour
saving index
Low labour saving index High labour saving index, it is a semi-automated
process, requires less manpower
Speed Slow. Conventional Approach can
drive in how many piles a day
Fast. Silent piling can drive in how many piles a
day
Table 9: Summary of differentiating factors
6.2 Batangas General Cargo Berth Construction, Philippines
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6.2.1 Background Information
The Batangas Port is strategically situated at the core of Calabarzon in South Luzon, near the area
of Metro Manila, where rapid development and industrialization is taking place. Having an
increase in container freights to 4.34 million tonnes, the port is regarded as the stronger dominant
positions in the area. The client for this project is the Philippine Ports Authority, with the design
by Pacific Consultants International and jointly constructed by Shimizu Corporation and the main
contractor F. F. Cruz.
Figure 40: Upgrading works at the Batangas Port
The purpose of the project is to expand the current container berth to accommodate the increasing
number of cargo ships calling at the Batangas Port. The newly expanded container berth seeks to
provide better efficient loading and unloading of general cargo.
Upgrading works on this project consists of the construction of three multi-purpose berths with a
total length of 467m, with a design sea depth of 7m. The berths have to be constructed offshore
and confined within the Ferry Berth and the General Cargo Berth. A double cofferdam structure
made up of continuous steel tubular sheet piles and U sheet piles is constructed to protect the
confined area from the high tidal waves.
6.2.2 Project Considerations
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General Cargo Berth
The Philippines Port of Authority was looking for alternative construction methods as they had
plans to shorten the construction time duration to meet the dateline of May 2004. Thus, speed is
the prime consideration for this project. There were several considerations identified for this
project which will be elaborated further.
Firstly, as the soil condition was relatively weak, the method of construction has to be able to
stabilise the weak ground condition. Hence, the project has decided to replace and improve the
soil. To begin, the sand around the berth area was dredged and replaced with good sand. After
which, vertical drain was used to improved the soil at the rear.
Secondly, the location of the berth is vulnerable to typhoon attacks. Hence the berth has to be
strong enough to withstand the impact of such natural disasters. In order to increase the strength of
the berth, this would mean incorporating a complicated structural design. Yet, the structural design
has to be simple enough to facilitate the ease of construction. The consultants finally concluded on
using the double cofferdam structure as it is simple and sturdy.
Thirdly, simple construction method should be employed in areas where the accuracy of works can
be monitored and managed. This would promote greater productivity.
Lastly, the construction of the berth involves works above water. This may pose certain constraints
as a temporary deck has to be erected to provide a platform for construction. Hence, the
consultants have to look into methods that allow for work to be done easily and efficiently above
water.
6.2.3 Piling method selected
The double cofferdam structure is made up of continuous steel tubular sheet piles and another row
of U sheet piles tied together by 65mm diameter steel rods at the top of the sheet piles. Depths of
piles are estimated to reach 27m and 18m respectively.
The press-in technique was chosen to install the piles into the ground. The press-in technology of
the silent piler adopts a self walking mechanism. This self walking mechanism is whereby the piler
moves in the direction of the constructed steel tubular sheet pile. As illustrated from the diagram
shown below, the clamping claws will rely on the reaction piles to support its own weight, while
pushing the pile into the seabed. Thereafter having successfully completed the insertion of one
pile, the saddle will be lifted to the next reaction pile, with the help of hydraulic jacks.
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Figure 41: Piling work process
Hence, this self-walking system allows for work to be done above water as the machine is able to
move by itself over the previously installed piles. Therefore, a temporary deck is not needed to
serve as a platform for the silent piler to carry out the piling works.
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Figure 42: Piling works above water Figure 43: Piling works above water
The elimination of the temporary deck saves a substantial amount of time. This allows the project
to proceed ahead with the piling works. Conversely, conventional piling methods require the
erection of a flat working platform.
6.2.4 Conclusion
The use of silent piling and its self walking mechanism eliminates the need for the construction of
a temporary deck. This fulfils one of the main considerations, which aims to meet the short time
frame.
Figure 44: Completion of General Cargo Berth Construction
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7. RECOMMENDATIONS
Silent piling is an advantageous method that provides advanced solutions for the sustainable
construction and is advised to use to comply with the five construction principles. However, since
this is a fairly young technique, it is estimated to be 10% to 20% more expensive compared to
other conventional methods that its usage has yet to be popularized and must be compromised with
the budget. Below is a list of circumstances, with an emphasis on the context of Singapore, in
which the use of silent piling is recommended because conventional methods cannot solve the
problems and therefore, the benefits of silent piling outweigh its cost.
7.1 Circumstances with Site Constraints
7.1.1 Sites with limited work space
In Singapore, there are a lot of congested sites with adverse working condition such as limited
access, minimum work space, overhead obstructions (e.g. under bridges, inside of existing
structures) and difficult temporary works (e.g. over water, above unlevelled ground), which make
conventional methods difficult or even impossible. However, with compact, lightweight machines
and temporary work-free, silent piling limits work space to just the area ultimately required.
7.1.2 Sites in proximity with residential areas
Being a developed country with the majority of land considered urban area, there are a lot of
construction sites that are adjacent to residential areas in Singapore. In such sites, large piling rigs
would not be possible because its operational energy would cause substantial noise, ground
vibration, soil displacement and settlement that will not only damage neighbouring structured but
also interfere with the functional needs of the city such as existing traffic and daily business
activities. With advance and innovative press-in method, silent piling produces almost no noise
and vibration. Moreover, since it requires minimum workspace (no temporary works), it will not
hinder other activities. Silent piling is especially good for road-expansion projects in which there
are a need to avoid interfering with the traffic.
7.1.3 Sites with geological difficulties
In certain ground conditions, cobbles and stones may be present creating very difficult piling
conditions. The use of conventional augering machines or heavy equipment for cast-in-situ
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diaphragm wall may risk collapse or overturning of the machines. Silent piling with the aid of an
integral pile auger can penetrate hard soil as it collapses around the augered areas while pressing-
in action in carried out simultaneously.
7.2 Circumstances with Time Constraints
Time constraint is among the most popular problems encountered in construction, not only in
Singapore but also in any other countries as well. Whenever the speed of construction is
required (for example urgent completion of emergency restoration works caused by natural
disasters or simply deadlines meeting), silent piling is a wise choice. Since there is no need to
restrict working time with the silent and vibration-free method even in environmentally
sensitive night works, the duration of the construction can be reduced. Moreover, the ability to
use multiple silent pilers simultaneously also speeds up the process.
7.3 Circumstances with Human Resource Constraints
Silent piling is a semi-automatic process in which it is controlled by a full radio operation
with a minimum number of personnel (often one technician is enough to manoeuvre the
machine). This helps reducing labour and hence very helpful when construction is in its peak
and there is a need for labour for other works.
7.4 Circumstances with Special Safety Requirements
Singapore has long been known for its stringent regulations on Workplace Safety and Health
Act for labourers. Since silent piling is controlled by full radio operation which allows
complicated manoeuvring with ease, it ensures safety for the operator as well as neighbouring
structures despite the adverse nature of the site.
7.5 Circumstances with Difficulty in the Removal of Existing Substructure
In developing urban areas, the demand to review and strengthen public facilities and
infrastructure is high. However, since they are often congested, it is very troublesome to
rebuild a new structure after complete removal of the existing substructure. With the gyro
press method in which a pile is installed by the "press-in" and "gyration" system, it is no
longer necessary to remove existing underground structures before new structures are
constructed. This method allows penetrating through existing foundation.
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Negative
Positive
Negative
Positive
Negative
Positive
Negative
Positive
Negative
Positive
Negative
Positive
7.6 Decision Tree
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8. IMPROVEMENTS
8.1 Fully Automated Silent Piler
Limitations of the current Silent Piler
Current silent piling is a semi-automatic process in which one operator uses full radio
control operation to manoeuvre the machine. This allows the operator to work from a
comfortable distance, while still being able to manoeuvre the machine and observe the piling
process. However, in the construction industry, there are situations in which the working
conditions are either too difficult or too dangerous. Dangerous working conditions include
natural disasters, such as flooding or volcano eruptions and even underground working sites
with harmful gases. Working in such harsh conditions would be impossible as it will
definitely endanger the operator.
Figure: Dangerous working conditions
Features of the fully-automated Silent piler
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Therefore, in order to further improve on the semi-automatic process, we propose a fully-
automated silent piling process. This is based on 3 procedures, as shown in the diagram
below.
Technician enters the data, regarding the piling process, into the automated silent piling logistic
system. The data would contain information, such as the number of pilings required, depth to be
pressed-in, length of the piles used and the position for the pile to be inserted.
The system will transfer the data to the satellite
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The Silent Piler will be connected to the automated silent piling logistic system by Global Positioning
System (GPS), and it will automatically press-in the piles after configuring the received data.
Prior to the automated piling process, the Silent piler technician will deliver and help to set up the
Silent piler at the designated position of the piling at the site. During the piling process, a team of
experts could be able to check and monitor the piling progress through satellite imagery, such as
Google Earth. The monitoring process could be done anywhere; on-site, or even off-site, in the
regional headquarters located outside the country. However, if things don’t go according to plan, the
team of experts will identify the problem and contact the nearest support centre. The support team can
then make their way to the silent piler to rectify the problem. Also, if the Silent piler becomes faulty,
signals will be automatically transmitted to the automated silent piling logistic system. This
automated feature will minimise work stoppage disturbance due to equipment faults. When the project
is successfully completed, technician will be sent to dismantle the Silent piler and transport it back to
the warehouse for storage.
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Benefits of the fully-automated Silent piler
If the fully-automated Silent piler is successfully implemented, it will be a technological
advancement that is unmatched in any current construction process. Most construction processes,
are either non-automated or semi-automated. Yet our fully-automated piling process would prove
to be highly efficient, as utilises manpower efficiently since the technician does not have to
constantly control one machine, with the full-automated approach, the technician can actually
work on several piling projects simultaneously. We are confident that the fully-automated Silent
piler will be able to allow one operator to work on up to 5 projects, as compared to the current
semi-automated Silent piler, whereby one operator is required for one project.
This fully computerised procedure will also mean that piling accuracy will be increased. Since
complicated piling coordinates will be fully configures and processed by the system, this
eliminates human error in calculations. Thus we believe that it will be considered a step forward
to revolutionising the piling technology.
Possible limitation of the fully-automated Silent piler
After critically analysing the benefits of the fully-automated Silent piler, we would like to
highlight a possible limitation, mainly that the fully-automated approach may not function in
region that leaks satellite reception, since it relies on the GPS. However, in such isolated regions
of the Earth, constructions site would face problems of noise, vibrations and space constraints.
Thus conventional piling approach, such as the vibro-hammer would be recommended for such
places as aforementioned.
Applications of the fully-automated Silent piler
The fully-automated approach allows the Silent piler to commence piling in unconventional
places. Such places refer to sites which are traditionally impossible to work in, as it would
endanger the lives of the operator. Yet the fully-automated approach would prove to be a viable
option to increase the possibility to work in impossible sites. For instance, it would enable the
work to commence even in a flooded area. It is common to construct pile elements to protect us
from strong currents before the occurrence of floods; the best solution will be to construct a
temporary retaining wall. However, during flooding, there are no current construction
technologies that will allow us to commence with piling works. But with this fully-automated
approach, piling can commence, making it possible to work in seemingly difficult situations.
8.2 Interchangeable Silent Pilers
One of the advantageous characteristics of silent piling is the ability to work with different types
of pile. However, because of the technique of the process which is to grab on the pile to press it in
using reaction force created by clamping on the previous piles, each kind of pile requires a
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different silent piler that is depending on the shape of the piles. For example, we need specific
silent pilers for U-sheet piles, Z-sheet piles, tubular sheet piles, etc. Therefore with the current
design, each kind of silent piler must be specifically produced. This method is uneconomical
because although the design for the chuck and clamp is different, the engine - the main body, is
the same for every kind. What we suggest is that instead of producing different silent pilers for
different piles, we re-design the joint between the main engine and the clamp and the chuck so
that the same main engine can be used for different clamp and chuck. Consequently, instead of
having to buy all types, a construction company only needs to buy different parts of the silent
pilers (main engine, chuck, and clamp) and use them interchangeably for different kinds of piles.
By this way, the cost can be substantially reduced.
Features of the interchangeable Silent Pilers
The picture on the left illustrates a silent
piler. As suggested above, we propose a
new silent piler that has an
interchangeable chuck. As shown below
is a more concise and detailed drawing of
the chuck indicated in red in the diagram
on the left.
Hence, in the above diagram, we can thus
see the different components which
facilitate the whole process of driving in.
As complicated as seen above, it would
also be impractical to change this whole
chuck. This is especially so in confined
sites where multiple types of sheet pile
might be required for usage. Therefore,
our group recommends that only the
following part as shown in the picture
below be detachable for the change.
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The dotted lines indicate the parts that will remained attached to the main body of the piler and this
includes the jacks and the backing of the chuck. The only detachable part will be the mould that caters
to the different sheet piles. It is also to take note that the bottom of the mould, which is attached to a
clamp is designed to be changeable as well. This is because the clamps are also designed to cater to
different sheet piles and is responsible for the process of pressing in. Indefinitely, there will be a need
to ensure proper load transfer from the detachable chuck to the main jacking system, which accounts
for a need of an experienced and skill engineer to supervise the process of changing the chuck. For
simplification, the chuck would look like the following pictures depicting our model of a silent piler.
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Benefits of interchangeable Silent Piler
Presently, the silent pilers available in market will only be able to press in a specific type of sheet
piles. Thus, with the recommendation of interchangeable silent piler, contractors can save on the
cost of purchasing multiple silent piler. The interchangeable Silent piler will be capable of piling
a variety of piles which range from 300 to 600mm. In order to accommodate different sizing, the
chunk designs that we propose will incorporate the flexibility of all sizes. This would be an
unique feature of the new interchangeable silent piler. Not only that, this could also help to offset
the initial cost of renting and owning several pilers. This is especially important since in the
construction industry, the variable cost will be the most important factor that ascertains a profit.
In addition, for unforeseen circumstances whereby any part of the piler might be damage, there is
only a need to change the particular part. This would thus be more cost efficient than to change
the whole machine.
Possible limitations of the interchangeable Silent Piler
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Chuck
Detachable part
However, as much as the interchangeable silent piler seemed feasible and attractive, there is still
possible limitation that could surface. Firstly, the time and space needed to change the chuck on
site might not be favourable since it would require space and skilled engineer as well as labour to
the change the chuck. However, similar to any other type of machineries that requires operating;
by familiarising the changing of chuck will make it a faster process. Furthermore, the space taken
up by the additional chuck will still be much smaller in comparison with other piler machines.
Nonetheless, the initial cost of this new and innovative machine would be rather high. However,
looking at the long term prospect in which cities will become more and more compacted, it would
only be a matter of time that silent pilers are adopted by the masses. Therefore, there is still a
benefit to start investing in such a new technology early and allowing the workers to familiarise
with the technology and hence improving the level of efficiency in the nearer future.
Application of the interchangeable Silent Piler
This technology is highly applicable to contractors that reside in urban landscape with a lot of
noise, vibration and site constraints. This is so since they will require a lot of different piler,
hence, by investing in one, instead of multiple machines, the payouts will be greater and the time
taken to offset the initial cost will be much smaller. Next, as mentioned above, it would only be a
matter of time when the landscape becomes complex and difficult for large and high quantity of
machineries to work on. Thus, the usage of interchangeable silent piler would then come in to be
extremely handy.
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APPENDIX
Interview with Dr Goh Teik Lim, General Manager of the Giken Seisakusho Asia
(Singapore)
1. Question: We understand that the silent piler is currently deployed for mainly sheet piling. Are
you looking into improving the silent piler such that it can be used for other types of piling
methods as well?
Answer: Giken relies heavily on the reaction principle/press-in principle. We will only invent
future products based on this principle. Currently, we do not have any plans to venture into
anything else that does not involve this principle.
The size of the machine is of great importance to us. We are researching into creating smaller
silent piling machines. The current machine used has four legs. In the near future, we are hoping to
cut the body from four forelegs to three in order to enhance efficiency and reduce the size of the
overall machine. Our president has the idea of making the machine portable, easy to mobilize and
readily supply them to all parts of the world.
2. Question: Are there any research to make the counterweights smaller since the company looks
at creating smaller machines?
Answer: The counterweight is only one minor part of the work. Our focus towards the
counterweights may not be that important. Get the piles going, time spent is minimal, borrow the
vibro-hammer to do the first few piles first.
3. Question: What are the limitations to your current silent piling technology?
Answer: The technology is still very young and the exposure to the market is still not there yet.
The first machine produced was in 1975 where it has been in the market for less than forty years.
The promotion of the silent piler globally has been poor so far. The silent piler first came out to the
world only after the 1990s. This was due to the protectionism system of the construction industry
in Japan for a long period of time; hence a lot of equipment and companies feel they do not need to
come onto the international scene. Therefore, not many people know about the silent piler.
Another limitation relates to cost. Investing in new machines means new investment. This means
contractors need to invest a portion of money which they usually do not prefer to touch at all.
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The price of using the silent piler is quite steep as compared to the conventional methods. If the
construction site does not have any noise, vibration or space concerns, the silent piler is not
encouraged due to the cost.
However, in urban settings, silent piler is recommended as this form of piling is always done in
space constraint sites. It also causes lesser noise and vibration.
A comparison between the use of vibro-hammer and silent piler, the silent piler is about 10% -
30% more expensive.
In terms of productivity wise, the vibro-hammer and the silent piler are comparable. However, the
speed of construction for silent piler is faster as it is able to go straight into the first piles.
Conversely, the other piling methods require a need to construct a temporary staging first.
There are not many constraints regarding terrain problems except that the other piling methods go
into two stages where they will need to auger first then put in piles. As for the silent pilers, these
two processes can be done simultaneously.
People prefer conventional methods as they are used to using it. The workers normally do not
prefer to learn about new machines too. Besides, time is needed to train the staff about the new
equipment.
Another limitation is that a particular silent piler can only be used for one type of pile.
4. Question: In your opinion, is it a viable option to invest in a silent piler?
Answer: Investing in a silent piler, or any construction equipment in particular, is a big move. We
cannot expect to reap the returns of the investment made over 1 day, it have to be done over a long
period. By using the old and traditional equipment that one contractor already have, the contractor
will see better economical sense, as they can lower the average of the cost of usage of equipment,
when the usage increases. In this scenario, they may not want to invest in the new equipment.
(One of the factors to consider is cost)
Costing: when it comes to new machines, it equates to new investment. Some contractors do not
have the capital to do so from day 1. To add on, contractors dislike investing this kind of money.
Depreciation (buy something of a value e.g. 5 years for machinery) allows the contractors to pay
the pinch of both old and new machines together such that operational cost can be averaged. On
the other hand, to purchase a new machine, there are no other machines to even out the cost. Giken
encourages the local contractor own the machine themselves, and slowly lose their dependence on
the Giken.
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Urban setting is a different thing. How competitive is the other method available? For giken, need
to see the merits as the whole picture. Need to see the whole construction process. Generally,
install giken 10%-30% more than conventional methods.
5. Question: Will you also provide the operator to operate the silent piler machines? Since they are
semi-automated and are considered more specialized than the normal piling machinery?
Answer: Manufacturer’s role is to sell the products. For the more sophisticated machines, we
provide with workers to do the jobs also. This also helps us in promoting our machines. After
certain forms of trainings have taken place, there is a need to train up the operators. All the time
the old system has been there, they prefer the old system. People dislike learning the new system.
The equipment has been done in an automatically driven sense that is holding the remote control to
operate the silent piler.
6. Question: Are your machines rented out or on sale?
Answer: The more sophisticated machine have to be rented out instead of being on sale. This is
because the machines are used for a short period of time and it cannot idle for too long.
7. Question: What type of project is the silent piler more applicable to?
Answer: The silent piler is more applicable to sites where there are noise, vibration and working
space constraints. It can be applicable to residential areas, river and road improvement works.
8. Question: Does the piles used have to be of a standard size?
Answer: The steel sheet piles have to be of a standard size
9. Question: How do you set up the silent piler and how long does it take to set it up?
Answer: The silent piler consists of three parts where it will be brought in from overseas
separately and assemble together. The setting up of the silent piler takes approximately a week.
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ANNEXES
ANNEX 1
Revised Permissible Construction Noise Limits for Worksites Within 150 Meters from Existing
Residential Premises
Monday to Saturday
Types of affected buildings 7am – 7pm 7pm – 10pm 10pm – 7am
(a) Hospital, schools, institutions of higher learning,
homes for aged sick, etc
60 dBA
(Leq 12 hrs)
50 dBA
(Leq 12 hrs)
50 dBA
(Leq 12 hrs)
75 dBA
(Leq 5 mins)
55 dBA
(Leq 5 mins)
55 dBA
(Leq 5 mins)
(b) Residential buildings located less than 150m
from the construction site
75 dBA
(Leq 12 hrs)
65 dBA
(Leq 1 hr)
55 dBA
(Leq 1 hr)
90 dBA
(Leq 5 mins)
70 dBA
(Leq 5 mins)
60 dBA
(Leq 5 mins)
revised limit:
55 dBA
(Leq 5 mins)
© Buildings other than those in (a) and (b) above75 dBA
(Leq 12 hrs)
65 dBA
(Leq 12 hrs)
65 dBA
(Leq 12 hrs)
90 dBA
(Leq 5 mins)
70 dBA
(Leq 5 mins)
70 dBA
(Leq 5 mins)
Sundays and Public Holidays
Types of affected buildings 7am – 7pm 7pm – 10pm 10pm – 7am
62 | P a g e
(a) Hospital, schools, institutions of higher
learning, homes for aged sick, etc
60 dBA
(Leq 12 hrs)
50 dBA
(Leq 12 hrs)
50 dBA
(Leq 12 hrs)
75 dBA
(Leq 5 mins)
55 dBA
(Leq 5 mins)
55 dBA
(Leq 5 mins)
(b) Residential buildings located less than 150m
from the construction site
75 dBA
(Leq 12 hrs)
65 dBA
(Leq 1 hr)
55 dBA
(Leq 1 hr)
90 dBA
(Leq 5 mins)
70 dBA
(Leq 5 mins)
60 dBA
(Leq 5 mins)
revised limit:
75 dBA
(Leq 5 mins)
revised limit:
55 dBA
(Leq 5 mins)
revised limit:
55 dBA
(Leq 5 mins)
© Buildings other than those in (a) and (b) above75 dBA
(Leq 12 hrs)
65 dBA
(Leq 12 hrs)
65 dBA
(Leq 12 hrs)
90 dBA
(Leq 5 mins)
70 dBA
(Leq 5 mins)
70 dBA
(Leq 5 mins)
ANNEX 2
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Southeast Asia. Japan: Giken Seisakusho International.
Goh, T. L., Katami, M., Motoyama, M. (2007). Press-in Piling Technology for Sustainable
Construction in Southeast Asia. Paper presented at the 2007 South East Asia Geotechnical
Conference, Kuala Lumpur, Malaysia.
Goh, T.L., Shinoda, Y., Hino, I. & Carlito, M. C. (2004), Press-in Piling: A Solution for General
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