Technical ReportPDF Available

Abstract and Figures

This report is an overview of vibratory and impact-vibration pile driving equipment. It discusses the history, types of equipment, types of piles driven, operational use and characteristics, vibratory mechanics and prediction methods of performance and pile resistance. NOTE: this is my most visited resource on Researchgate. My interest on this topic is ongoing, visit the project link to learn more.
Content may be subject to copyright.
Terms and Conditions of Use:
this document downloaded from
vulcanhammer.info
the website about
Vulcan Iron Works
Inc. and the pile
driving equipment it
manufactured
All of the information, data and computer software (“information”)
presented on this web site is for general information only. While every
effort will be made to insure its accuracy, this information should not
be used or relied on for any specic application without independent,
competent professional examination and verication of its accuracy, suit-
ability and applicability by a licensed professional. Anyone making use
of this information does so at his or her own risk and assumes any and all
liability resulting from such use. The entire risk as to quality or usability of
the information contained within is with the reader. In no event will this web
page or webmaster be held liable, nor does this web page or its webmaster
provide insurance against liability, for any damages including lost prots, lost
savings or any other incidental or consequential damages arising from the use
or inability to use the information contained within.
This site is not an ofcial site of Prentice-Hall, Pile Buck, or Vulcan Foundation
Equipment. All references to sources of software, equipment, parts, service or
repairs do not constitute an endorsement.
Visit our companion site
http://www.vulcanhammer.org
Page 1 of 50, 1989,1992 Don C. Warrington
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING VIBRATORY AND IMPACT-VIBRATION PILE DRIVING
EQUIPMENTEQUIPMENT1
Don C. Warrington, Vulcan Iron Works Inc.Don C. Warrington, Vulcan Iron Works Inc.
Introduction
In terms of the history of technology and the speed of its advance, it has been a
long time since D.D. Barkan's first vibratory pile driver turned its eccentrics in
the field back in 1949. In the Soviet Union, where this took place, Joseph Stalin
was still very much in charge, and the country was recovering from the horrible
combination of the Purge and World War II. In the U.S., contractors were
happily beating away at their piles with Vulcan, Raymond, and MKT steam
impact hammers, and in Germany the Delmag organization was emerging from
its own war reconstruction to begin the wordwide broadcasting of a large
number of red diesel hammers.
Vibratory hammers have gone on to become an important tool in the installation
of a large number of pile types, and yet there is a great deal that is not under-
stood about how they work and what kind of results one can expect from them.
What is the bearing capacity of a pile driven by vibration? What kind of re-
sponse will various soils give when vibrated? And what happens when you add
impacts to the system, as you do when using an impact-vibration hammer?
All of these questions and others are subjects of ongoing research in many
countries; however, once this is all done, it needs to be disseminated, and here
too there has been inadequate effort, whether for lack of resources or desire to
keep trade secrets.
In late 1989 Mr. Chris Smoot of Pile Buck approached me about putting together
such an article for the newspaper and an upcoming series of books he was
publishing. In response to this, I put together both material I had already
written and other materials to make up the article "Vibratory Pile Driving Equip-
ment", which appeared in Pile Buck the following year.
As is the case with many projects, once the project itself is over one realizes that
the work is ongoing. To begin with, there were many items in the original
article that needed expansion and also some new topics needed covering; many
of these were pointed out by readers. In addition to that, it became obvious that
no comprehensive treatise on the subject of vibratory hammers was complete
1This article was originally published in 1989 in Pile Buck. It was subsequently revised in 1992 and published there
again. A few revisions have been made for this internet edition. All of the information and data presented here is for
general information only. While every effort will be made to insure its accuracy, this information should not be used or
relied on for any specific application without independent, competent professional examination and verification of its
accuracy, suitability and applicability by a licensed professional. Anyone making use of this information does so at his or
her own risk and assumes any and all liability resulting from such use. The entire risk as to quality or usability of the
information contained within is with the reader. In no event will this web page or webmaster be held liable, nor does this
web page or its webmaster provide insurance against liability, for any damages including lost profits, lost savings or any
other incidental or consequential damages arising from the use or inability to use the information contained within.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 2 of 50, 1989,1992 Don C. Warrington
without the inclusion of material on impact-vibration hammers, a type of ma-
chine that is both very much like and very different from the vibratory pile
driver. This became especially apparent when I co-authored the paper "Develop-
ment and Improvement of Impact-Vibration Pile Driving Equipment in the
USSR" with Mr. L.V. Erofeev of VNIIstroidormash, the construction equipment
research institute in Moscow. Both of these issues are addressed in the current
work.
Those who are familiar at all with my writings on this subject have noted the
extensive coverage of Russian research and practice. The technology was first
put to the field in what was then the Soviet Union, and there is quite a lot of
written output on the subject in Russian, but as is the case with much Russian
information it was a mystery to most Americans. Since I first set to work on this
subject in 1988 (which coincided with my first visit to Russia), we have seen the
end of the Soviet Union and the Cold War and the reemergence of Russia as a
nation once again.
Once technical note that belongs right at the start is a distinction between vibra-
tory equipment and impact-vibration equipment. For the purposes of this arti-
cle, vibratory pile driving equipment refers to equipment whose forces are
generated in an alternating sinusoidal force with no impact coming from the
exciter, which impact-vibratory machines have both the sinusoidal force and
impact within the exciter itself. These mechanisms will be explained in more
detail later.
No work such as this can ever come to reality without the help of others. There
are two special people whom the author would especially like to recognize. The
first is Mr. Charles L. Guild of American Equipment and Fabricating. His contri-
butions to the advancement of foundation installation in general and vibratory
pile driving technology in particular are too numerous to list here; such an
enumeration is a work unto itself. For this article he clarified many points
concerning the resonant machine. More importantly, Charlie is a wonderful
Christian and has been an inspiration to me and others who have had the priv-
ledge to know and work with him.
The second is Mr. Lev V. Erofeev of VNIIstroidormash, the Russian organization
for Constructional Road-Building and Municipal Machinery. He was in reality
the main author of the article on impact-vibration pile driving equipment, and
his willingness to share information of this and other topics of Soviet and now
Russian pile driving technology have helped to dispel the mystery surrounding
these subjects and thus enable us to more greatly appreciate the accomplish-
ments.
Others who have contributed to this article include Messrs. E.A. Narozhnitskii
and M.L. Pevzner of the Leningrad Experimental Works of Construction Ma-
chinery; Ms. Sherrill Gardner of the Naval Civil Engineering Laboratory; Mr.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 3 of 50, 1989,1992 Don C. Warrington
Richard Nelson of Pile Equipment, Inc.; Dr. David M. Rempe, consulting geo-
technical engineer; Messrs. Bill Harrison and W. David Engle of Vulcan Iron
Works Inc.; Dr. Michael O'Neill of the University to Houston; and Mr. Christo-
pher Smoot of Pile Buck for enabling the publication of this and related works.
Finally this author would like to make an important "vibratory" acknowledge-
ment by citing Haggai 2:6-7: "This is what the Lord Almighty says: `In a little
while I will once more shake the heavens and the earth, the sea and the dry
land. I will shake all nations, and the desired of all nations will come, and I will
fill this house with glory,' says the Lord Almighty."
Chapter I
HISTORICAL DEVELOPMENTHISTORICAL DEVELOPMENT
§1 Development of Vibratory Equipment
The first vibratory pile driver used was in what was then the Soviet Union, a
model BT-5 developed and first used under the direction of D.D. Barkan. This
hammer had a dynamic force of 214 kN and the eccentrics rotated at 41.67 Hz,
powered with a 28 kW electric motor. Used in the construction of the Gorki
(now called once again Nizhni-Novgorod) hydroelectric development, the ham-
mer drove 3700 sheet piles 9-12 m long in 2-3 minutes each.
The Soviets went on to develop a large variety of vibratory pile drivers and soil
drilling equipment in the 1950's. They also first licensed their technology to the
Japanese, who with several concerns have developed an extensive array of
vibratory hammers. This technology has since spread worldwide, with such
concerns as PTC and Tramac in France, Müeller, Tünkers and MGF in Germa-
ny, Tomen in Japan and ICE Europe in the Netherlands being well established in
the field.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 4 of 50, 1989,1992 Don C. Warrington
Figure 1 MKT V-10 Vibratory Hammer
The first American made hydraulic vibratory was the MKT V-10, which they
introduced in 1969, although both
Vulcan and Foster had introduced
Japanese and French vibratory pile
drivers respectively in the early
1960's. A diagram of this machine is
shown in Figure 1. This pioneering
machine differs from most current
vibratory pile drivng equipment in
several respects. The first is the
suspension; in common with the
practice of the time, the V-10 used
steel coil springs to provide dampen-
ing for the crane boom and hook,
whereas now most machines use
rubber springs. The second con-
cerned the eccentrics; the V-10's
eccentrics were long (a practice
borrowed from vibratory screens and
seperators) and mounted crossways
on the machine. A motor was cou-
pled to one of the eccentrics; gears
transmitted the power to the rest.
Most machines today mount the
eccentrics from front to back of the
case, and drive them either directly or
through a speed changing pinion
gear.
From this beginning, the unique practices in the U.S. have lead to the evolution
of a distinctive style of vibratory hammer in the U.S., and this has been followed
elsewhere. Today it is embodied to a greater or lesser degree in the Vulcan, ICE
(America and Europe), MKT, Foster, Casteel, and HPSI units that are on the
market. In addition to the changes mentioned above, these characteristics
include slim throat hammers for sheet pile driving, hydraulic drive, and high
power motors, pumps, and engines.
Classifying vibratory pile driving equipment can be a complex business, but the
most important division can be made on the basis of frequency, with the result-
ant relationships between dynamic force and eccentric moment. These quanti-
ties will be dealt with in more detail in §14. There are three basic divisions,
which are as follows:
1)Low frequency machines: These are vibratory drivers with a vibrator frequen-
cy of 5-10 Hz, used primarily with piles with high mass and toe resistance, such
as concrete and large steel pipe piles. They tend to have large eccentric mo-
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 5 of 50, 1989,1992 Don C. Warrington
ments to achieve their dynamic force, with high resultant amplitudes. An exam-
ple of this type of machine is the Russian VPM-170, which is used by the Rus-
sian Ministry of Transportation and which is the largest made in the country.
This machine produces a maximum dynamic force of 1,700 kN at its maximum
frequency of 9.17 Hz and eccentric moment of 510 kg-m. This machine is de-
signed primarily to drive caissons up to two (2) meters in diameter and is bolted
to the pile rather than clamped. The Tomen organization in Japan has produced
many machines of this type as well.
Figure 2 VNIIGS B-402 Vibra-
tory Driver in St. Petersburg,
Russia
2) Medium frequency machines: These are drivers with a vibrator frequency of
10-30 Hz, used for piling such as sheet piles,
small pipe piles, etc.. An example of this type
is shown in Figure 2, a B-402 vibratory ham-
mer actually driving Larssen type sheet pile on
a tunnel construction job in St. Petersburg.
This unit has a maximum dynamic force of
270 kN while operating at its rated oscillation
frequency of 23.8 Hz and its maximum eccen-
tric moment of 12 kg-m. These machines
make up the majority of vibratory pile drivers
in use today, as they combine the dynamic
force necessary to excite the soil, the correct
frequency to properly interact with most soils,
and sufficient amplitude to get through the
hard spots in the soil.
3) High Frequency Machines: These consist of
all machines which vibrate at frequencies of
more than 30 Hz. They are of two basic types.
The first are machines in the 30-40 Hz range which are designed primarily to
minimize vibration of neighboring structures. These have been developed
simultaneously both in Europe (ICE, Tünkers, PTC) and in the U.S. (Vulcan).
The primary advantage of these machines is their lowered transmission of
ground excitation to neighboring structures. These machines' frequencies are
not high enough to improve driving and in some cases these machines have
problems in overcoming toe resistance.
In a class by itself is a resonant pile driver, and the most significant machine of
this type is the Bodine-Guild resonant driver, first introduced in the early 1960's.
The central principle of the resonant driver is to induce resonant response in the
pile, thus facilitating driving and extracting. The resonant driver operates at
frequencies in the range of 90-120 Hz; in most cases the driving took place at
the half wave frequency of the pile. The ability to achieve this response was
dependent upon properly matching the frequency range of the machine to the
length of the pile; in cases where this was not possible in a normal hammer-pile
setup, a heavy wall follower connected the pile with the hammer. On the other
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 6 of 50, 1989,1992 Don C. Warrington
hand, when the pile was exceptionally long, second and third overtones could be
achieved; this was the case when a 273mm (10.75") O.D. wall pipe 115.8m (380')
long was driven. Although in principle this concept has held great potential, the
mechanical complexity of this machine has withheld it from extensive use.
§2 Development of Impact-Vibration Hammers
The term "impact-vibration hammer" refers to a type of vibratory pile driver that
imparts both vibrations and impacts to the pile during operation. Based on
theoretical work done during the Second World War by himself and others, S.A.
Tsaplin prepared the first experimental impact-vibration hammer in the Soviet
Union in 1949. The specifications of the hammer and test setup are shown in
Table 1, and a drawing of this machine is shown in Figure 3. In field tests his
impact-vibration hammer was welded to the top of metallic tube 110 mm in
diameter, 8 mm wall thickness, 2.6 m long and with a mass of 200 kg. The
hammer then drove the tube into a variety of sandy, sandy loam, and clay soils.
A comparison was made here of the effect of driving by the impact-vibration
mode versus the vibration mode, the latter of which was achieved by the com-
plete blocking of the springs. The tests made it possible to establish that the
efficiency of the impact-vibration driving is substantially higher with regard to
both the maximum driving depth possible and the pile sinking velocity, and that
the efficiency of the driving increases with increasing amplitude of the vibration
exciter vibrations.
Table 1
Hammer and Test Setup for Tsaplin Impact-Vibration Hammer
Nominal rotational speed, Hz 48
Permissible frequency range w/generator, Hz 40-200
Power, kW 1.6
Exciter mass, kg 75
Overall mass, kg 95
Test Stand
Material Reinforced Concrete
Mounting Rigidly Attached to Hammer
Mass, kg. 500
Generator
Power Output, kW 50
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 7 of 50, 1989,1992 Don C. Warrington
The first broad practical application of the impact-vibration hammer took place
in the construction of the Stalingrad (now Volgograd) power plant, where in the
construction of the anti-filtration wall under the dam "Larssen-5" piles were
driven to a depth of 13 m with the driving at the last site in sandstone of medium
firmness. On this and other jobsites, the impact-vibration hammers were able to
outdrive conventional vibratory hammers, air/steam and diesel hammers.
Figure 3 Tsaplin Impact-Vibration Hammer
The success of this and other jobsite and laboratory situations has led to the
spread of the use of impact-vibration hammers, not only in Russia but also in
other countries, especially those of the EC where manufacturers such as Menck
and PTC have taken up the production of these units. There are no impact-
vibration hammers manufactured in the U.S. at present.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 8 of 50, 1989,1992 Don C. Warrington
Chapter II
CONSTRUCTION AND OPERATION OF EQUIPMENTCONSTRUCTION AND OPERATION OF EQUIPMENT
§3 Vibratory Hammer Exciters
Engine
Pump Hoses
Clamp
Motor
Case
Suspension
Figure 4 Basic Vibratory Hammer System
Although there are many variations in design and construction, the vast majority
of vibratory hammers are of the configu-
ration shown in Figure 4. Briefly, there
are two main components of the system:
the exciter, which produces the actual
vibrating force, and the power pack,
which provides the usable energy for the
motor(s) on the hammer to spin the
eccentrics.
We first need to look at the exciter; it is
divided into three parts:
1)Vibrator case: This contains the eccen-
tric weights and does the actual vibra-
tion. The sinusoidal force is generated
by the rotation of the eccentrics (see
§14); thus, these eccentrics must be
somehow both driven and synchronized.
The most common way to accomplish this is through a gear system. The gears
can actually function in various ways, depending upon how they are set up.
Generally the eccentrics are mounted to the gear system, either partially or
entirely; in either case the mounting is rigid. In some vibratory hammers, this
rigidity is insured by making the gear a one piece eccentric. Several types of
gears have been used in vibratory hammers, including spur, helical, and bevel.
All types work best when the teeth are small but strong enough to transmit the
power. Large teeth have been used extensively in vibratory hammers over the
years, but small ones are quieter, more efficient, and more reliable.
Other schemes of synchronization are a)there are no gears, and most of the time
the amplitude of the system synchronizes their rotation, each eccentric driven
by its own motor (Tünkers), or b)the gears are synchronized by a chain and
each eccentric is driven individually (H&M).
In any case, the dynamic force generated by the eccentrics is transmitted to the
case by the use of antifriction bearings, which also facilitate rotation. These can
be cylindrical, spherical ("screen" bearings), or ball, but to work properly they
must be sufficiently large for the load and adequately lubricated, either by a
pump system or a well designed splash system.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 9 of 50, 1989,1992 Don C. Warrington
Geared eccentrics can be connected to the motor either by a pinion, or through
belts or chain drives. For the latter two the motor is mounted on the static
weight; a pinion drive requires that the motor be mounted directly to the vibra-
tor case. Pinions are used as torque converters, which make optimum use of
motors at their preferred operating speeds.
2)Clamp:This connects the vibrator case to the pile and thus transmits the vibra-
tor's power from the vibrator case to the pile. Generally speaking, most clamps
pinch the pile using a hydraulic cylinder and jaws, thus making a frictional
connection. A few vibrators actually bolt or pin the pile to the vibrator case, as
was done with the old Vulcan or MKT impact extractors. Some clamps (Foster)
use some kind of leverage to enable the use of a small cylinder to generate a
large force. For hydraulic clamps, both lever and direct cylinder clamps are
shown in Figure 5.
Figure 5 Hydraulic Clamps for Vibratory Hammers (after Tseitlin et.al. (1987))
3)Suspension: This is connected to the vibrator case by rubber or metal springs.
In driving this provides additional weight to the system to force the pile into the
ground without degrading the vibration of the system, although with most units
additional bias weight can be attached to the suspension. In extraction the
suspension system transmits static pull while dampening out vibration and thus
protects the crane boom. For this to be effective the springs must be sufficiently
soft and the bias weight sufficiently heavy to insure a suspension natural fre-
quency that is much lower than the vibrator's operating frequency. Occasionally
additional static weight is helpful during driving and the weights which accom-
plish this (called "bias weights") are attached to the suspension.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 10 of 50, 1989,1992 Don C. Warrington
§4 Impact-Vibration Exciters
Although impact-vibration hammers share common constructional features with
their vibratory relatives, there are
important differences. Such varia-
tions can be seen in the machine
shown in Figure 6. In common with
more conventional vibratory ham-
mers, it contains counterrotating
eccentrics which impart vertical
vibrations; however, these are
contained in a head which is not
rigidly connected to the pile but is
free to some degree. This freedom
enables the unit to impact the pile at
a rate higher than conventional
impact hammers. The alternating
force of the eccentrics takes the
place of the air, steam, diesel com-
bustion or hydarulic fluid in moving
the head up and down like a ram,
with impact at either the top, bot-
tom, or both ends of its "stroke".
Although this can produce varia-
tions in the eccentric rotational
speed of up to 40% (as opposed to the 5% or so normal for vibratory hammers),
this variation generally does not impede the continuous, stable operation of the
equipment.
Some of the various parts of these hammers are discussed below:
Exciter/Head: The exciter of these machines is similar in general principle to
strictly vibrating machines, with eccentrics driven by motors. With impact-
vibration hammers, the exciter has a constant source of amplitude within the
springs, and so the eccentrics are usually not synchronized with gears, each one
driven by a motor. Bearing life with these machines is critical, and many of
them must be used in the vibratory mode a good deal of their operation.
Frame and Springs: Frame design of these machines is critical since the frame
provides both the regulation of the machine and its connection to the pile. The
regulating springs are generally coil springs. The machine's vibration within the
springs is regulated by both the spring rate and the pretensioning of the springs.
The latter can be either fixed or regulated by hydraulic or electric means. Part
of the machine's force on the pile is also transmitted by the springs if the frame
is clamped to the pile.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 11 of 50, 1989,1992 Don C. Warrington
Pile Connection: The most elementary of impact-vibration machines have no
pile connection (or frame) at all and rest on the top like impact hammers.
Although hydraulic clamps similar to ones used in vibratory hammers can be
used, other schemes to keep the frame on the pile include simply making the
frame heavier than the upward spring force or bolting the machine to the pile.
§5 Power Packs for Vibratory and Impact-Vibration Equipment
Turning to the power pack, a few vibrators, such as the Bodine-Guild resonant
drivers, some of the early Soviet vibrodrilling machines, and some Japanese
units, drive rotating eccentrics straight from diesel or gasoline engines by
mechanical couplings. However, most vibratory or impact-vibration hammers
transmit energy from the prime mover to the eccentrics through either electric
or hydraulic systems. Since construction sites are usually remote, transportable
power sources have been developed for vibratory hammers. These are referred
to as power packs (for hydraulic units) or generator sets (for electric units).
These units are similar for both vibratory and impact-vibration equipment.
Electric systems: These usually employ three-phase induction motors driven at a
single frequency, which has encouraged the development of many systems to
vary the eccentric moment and thus the driving force. In some cases electric
vibratory hammers can be driven from a nearby three-phase mains, obviating
the need for a generator set. The hammer thus only requires a switchbox to
control it. A separate, small power pack, driven with an electric motor, is re-
quired to operate the hydraulic clamp, if there is one. This can either be on the
ground or mounted on the static overweight. Electric systems are less and less
popular because of maintenace and reliability considerations.
Hydraulic systems: For a variety of reasons hydraulic systems have become
dominant, and the major manufacturers, such as Vulcan, ICE, and MKT, employ
hydraulic drive almost exclusively. These systems use a diesel engine to drive a
hydraulic pump, which in turn drives the motor on the exciter. A reservoir of
varying size is used to store hydraulic fluid, to make up fluid in case of leakage,
and to assist in the cooling of the fluid. A system of valves is used to control the
fluid flow, both in starting and stopping the machine and during operation.
Beyond these basics, there are specific differences between the various hydrau-
lic power packs available; they are:
1) Pump Drive and/or Gearbox: The hydraulic pump is connected to the engine
through a pump drive; sometimes this pump drive is a gearbox as well, acting as
a speed changer to optimize the pump, while in others a direct drive is em-
ployed, eliminating gear losses.
2) Clamp Pumps: Some units have separate pumps for the hydraulic clamps and
some integrate these into the main power source. Impact-vibration hammers
that do not have a clamp on them do not need a clamp circuit.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 12 of 50, 1989,1992 Don C. Warrington
3) Variation of Frequency and Force: Both of these can be varied either by using
variable displacement pumps in the power pack or by simply varying the engine
speed. Variable displacement pumps can have very sophisticated flow control
mechanisms.
4) Control Type: These units can employ air, electric, or manual controls for the
hydraulic circuitry. Manual controls are the simplest; however, they confine the
operator of the unit to the power pack's location, which, depending upon visibili-
ty and other factors, may not be the most convenient place from whence to
operate the machine. Remote controls allow more flexibility for the operator
but are an added expense and source of trouble for the machine.
5) Enclosure: Some power packs have a sheet metal enclosure and some do not.
The principal advantage of an enclosed power pack is protection from weather
and criminal activity. Enclosures are also helpful if they provide sound deaden-
ing, although many do not. Open power packs are more economical and there
is better access to the parts for service.
6) Open and Closed Loop Hydraulic Systems: Both appear on power packs in
this application. Closed loop systems allow for better controlled starting, run-
ning, and stopping of the machines, but have traditionally been more complicat-
ed, and the power packs less adaptable to other applications.
In some cases, the crane hydraulic system can be employed to power the vibra-
tory hammer. Although this eliminates the external power pack and diesel
engine, all of the control and operational features of these integral power units
are the same.
Chapter III
PILING DRIVEN BY VIBRATORY AND IMPACT-VIBRATION MACHINESPILING DRIVEN BY VIBRATORY AND IMPACT-VIBRATION MACHINES
Vibratory pile drivers have been used to drive and extract virtually any type of
piling used, although the specialty of vibratory and impact hammers is some-
what different. In the United States, the main application of vibratory hammers
is the installation of steel, non-displacement piles where a definite bearing
capacity is not required. This last condition is because of the state of the art of
vibratory capacity prediction; this will be addressed later in the article. Vibra-
tory hammers are also sometimes not as effective as impact ones in stiff, cohe-
sive soils, or displacement piles that develop a good deal of toe resistance.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 13 of 50, 1989,1992 Don C. Warrington
§6 Steel Piles
Figure 7 Vibratory Hammer
Installing Sheet Piling
Sheet Piling: Figure 7 shows a hydraulic vibratory hammer installing sheet
piling. The sheeting is set up according to normal
American practice, namely to set the wall in place
and then to drive the pile to the desired depth.
This practice requires that the vibratory hammer
be no wider at the throat than about 355mm, as
the hammer must clear the adjacent piles. In
driving sheeting in this way, it is also normal to
drive the sheets two at a time, using a jaw with
two sets of teeth and a recess between them large
enough to accommodate the interlock.
Figure 2 shows an alternate method of driving
sheeting with a vibratory hammer. Here the
sheets are set as they are driven. As a rule, in this
case the sheets are driven one at a time. No
matter how sheet piling are driven, they should
not be driven at penetration velocities of less than
5 mm/sec.
Impact-vibration hammers have been designed
for and used with steel sheet piling in soils that
produce high toe resistances and thus are not
congenial to vibratory driving. Hammers that are
used for both driving and extraction are able to
impact both upwards and downwards. Impact-
vibration hammers for sheet piles generally are
equipped with clamps instead of an inertial frame.
H-Beams: Figure 8 shows a vibratory hammer driving an H-Beam. The condi-
tions are similar to driving sheeting; however, when the pile's batter angle is
critical, the vibratory hammer can be mounted in a set of leaders much as is
done with an impact hammer. In addition to a bearing application (where the
beam might be impacted to refusal), vibrated H-Beams are used for soldier
beams and in slurry wall construction.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 14 of 50, 1989,1992 Don C. Warrington
Figure 8 Vibratory Hammer Installing H-
Beams Figure 9 Vibratory Hammer Installing
Caissons
Caissons and Pipe Pile: Figure 9 depicts a hammer driving a caisson. Caissons
are a versatile item, extensively used with drilled shafts. To drive these, a spe-
cial device called a caisson beam is employed. This is a horizontal slide with a
set of two clamps attached to it. The clamps affix the pile to the hammer on
opposite sides of the caisson. The clamps are locked to the slide during use but
can be moved along the slide to enable a caisson beam setup to drive a variety of
pile.
The equipment setup for caissons is duplicated with pipe pile. Generally it is
best to vibrate pipes open ended, although some closed ended installation is
done. An example application of driving pipe pile is the installation of pipe piles
for offshore structures, such as petroleum production platforms. For some of
these two caisson beams with two sets of clamps are used, the beams being
configured in an "x" arrangement.
§7 Concrete Piles
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 15 of 50, 1989,1992 Don C. Warrington
Figure 10 Impact-Vibration Hammer
Installing Concrete Pile
Concrete pile installation with vibratory hammers is rare in the U.S. but more
common abroad. It is done with both pris-
matic (square and octagonal) and cylinder
pile. As concrete pile is always displacement
pile, the vibratory hammer must develop
some toe impact by raising and lowering the
pile during the vibration cycle, thus allowing
penetration. This is generally accomplished
using low frequency vibrators with high
amplitudes. Resonant machines have also
been used to drive concrete piles, with a
clamp which could tightly press against the
pile. An alternative to this is to use an im-
pact-vibration hammer, which can more
effectively deal with high toe resistance than
can a vibratory hammer; indeed, the need to
drive concrete piles has been one of the most
important factors in the development of these
hammers (see Figure 10).
§8 Wood Piles
As it is almost exclusively bearing pile, wood is rarely vibrated in the U.S.
Extraction of wood pile, however, is common, and the vibratory hammer is an
effective tool for this purpose. The wood pile can be extracted intact in this
manner. Special wood clamps are used for this purpose.
Chapter IV
EQUIPMENT OPERATIONEQUIPMENT OPERATION
As we have seen, vibratory and impact-vibration hammers vary from manufac-
turer to manufacturer and model to model in their construction and operation;
however, there are things which are common to all of this type of equipment.
This section deals with some of these items. The guidelines below presuppose
equipment with a remote power unit equipped with an engine. Equipment
powered from an external mains will be similar except for the lack of an engine.
§9 Safety
Safety is basically common sense. There are standard safety rules, but each
situation is different. Your common sense and experience will be your best
guide to safety. Always be alert to problems and correct deficiencies promptly.
Since Russian machines have been described in detail, the following from the
operation manual of the B-402 may prove of interest:
Persons are allowed to operate the Vibratory Pile Driv-
er who have reached eighteen (18) years, passed the
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 16 of 50, 1989,1992 Don C. Warrington
training and the knowledge check in the safety of
building, handling, and piling works, and received the
certificate for the right of operating the Vibratory Pile
Driver, studied the present Technical Description and
Operating Instructions, learned by practice the opera-
tion of the Vibratory Pile Driver, and have an experi-
ence in driving and removing piles.
Work supervisors must carry out a detailed briefing of
the persons who are to operate the Vibratory Pile Driv-
er on rules and safe techniques prior to the works. The
persons who have not been present at the safety brief-
ing are not allowed to work.
The one thing you must do FIRST
First, take time to take your operating manual, go to the exciter and power pack,
and review all of the operating and safety features in the manual, and to like-
wise familiarize anyone else working on or with the equipment with these
features.
Things you should NEVER do
Never allow unauthorized or unqualified people to either operate, maintain, or
come within thirty (30) meters of the equipment.
Never allow anyone to stand directly under or within at least three (3) meters of
the hammer or pile being driven during operation. Failure to do so could result
in injury or death by being struck by falling parts, rocks, or dirt that the hammer
has picked up by being laid on the ground.
Never operate the power pack's engine in a closed area. The breathing of the
fumes can be fatal.
Never smoke or use open flame when servicing batteries. Proper ventilation is
necessary when charging batteries. On units with a power pack enclosure, all of
the doors of the unit must be open during battery charging.
Never smoke when filling fuel tank or hydraulic reservoir, or for that matter
while anywhere near exciter, hoses, or power pack. Diesel fuel, gasoline, and
hydraulic fluid are all very flammable.
Never adjust or repair the unit while it is in operation, except with the main
motor and clamp controls provided for that purpose. If you need to make any
other adjustments, shut the entire system down first.
Never attempt to operate the engine with the governor linkage disconnected.
Never store flammable liquids near the engine.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 17 of 50, 1989,1992 Don C. Warrington
Never unclamp the exciter from the pile when there is any line pull on the
suspension or when the hammer is still vibrating.
Things you should ALWAYS do
Always store oily rags in containers. If these get into an hydraulic system, you
will have a mess.
Always remove all tools from unit before starting.
Always be sure that, with hydraulic systems, all pressure is out of the system
and that all pressure gauges read zero before you start working on the hydraul-
ics of the system. The high pressure fluid in hydraulic lines can be very dan-
gerous if it escapes, such as in a hose break or loosening of a fitting or compon-
ent. Even when you think the system pressure is zero, you should proceed with
extreme caution, assuming all the while that all of the lines are still fully pres-
surized. This means primarily that you should open all fittings and connections
slowly until you see that there is no pressure on that particular connection.
Keep your face and body away from the potential line of fire of any fluid while
you are working with hydraulic connections.
Always make sure that you make any hose fittings or connections very tight
when you reassemble them. Failure to do so can result in the hoses coming
loose, resulting in hoses flying around, hydraulic fluid spraying everywhere, and
people being injured or killed by all of this. This also applies to any bolted or
otherwise fastened connection on either the exciter or power pack.
Always make sure that electrical systems are properly grounded during opera-
tion. Also, make sure that they are not connected to any power source in any
way and that there is no voltage of any kind in the system before servicing same.
Always make sure that electrical connections and wiring are tight and complete-
ly insulated to prevent shock if accidentally touched. This is especially import-
ant in waterfront or marine situations; uninsulated wire can result in widespread
electrocution of wild and human life. Any electrical fuse, breaker, or control
boxes must be closed before any kind of operation.
Always be sure to wear gloves and other protective clothing while working on
any part of the system, or even better to wait until the system has cooled down.
Hydraulic components, electrical wiring and switchgear, and the engine get very
hot during operation.
Always make sure that the pile is firmly gripped by the jaws when clamping.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 18 of 50, 1989,1992 Don C. Warrington
§10 Basic Operation
Rigging: To permit lifting of the hammer, a wire rope must be secured from the
crane line to the lifting hole or pin on the suspension. In choosing the wire rope
for any unit, a generous safety factor should be used. Wire rope which is worn
or frayed must be discarded. Several turns of a smaller diameter cable will
usually last longer than one turn of a large diameter cable. Make sure that the
wire rope assembly you use has at least double the capacity of the suspension.
For hammers that use a lifting shackle, make sure there are no loose bolts, nuts,
or pins in the shackle.
Engine Start-Up: Read the engine start-up procedure in the manufacturers
operation manual. Follow any applicable instructions.
Do not start the power pack if the temperature of the hydraulic oil is below -18°
C.. The case oil and/or fluid temperature should be at least 0° C. before starting
the exciter at a slow speed. After starting engine, let it run slowly for at least
five minutes.
In Use: Complete all applicable preparation for operation as described in the
hammer's operating manual. Perform any required periodic maintenance before
operation. The user should also be thoroughly familiar with the inner workings
and control operation of the power pack/generator and exciter before operation.
An understanding of how the unit works will give the operator a feel for what is
happening and will also be invaluable in troubleshooting the unit should a
problem arise.
Do not operate the exciter at full speed if the temperature of the hydraulic fluid
and/or case oil is below 15° C.. If the temperature of the hydraulic fluid or case
oil is below that level, set the engine at a moderate speed and start the hammer.
Allow the exciter to run until the fluid and/or oil reaches the required tempera-
ture. Full speed operation is now permissible.
Make sure the exciter is positioned parallel to the pile and that the full length of
the jaw will make contact with the pile when clamped. Engage the "clamp close"
control. The clamp will close in a couple of seconds. The operator should make
sure that the pile is firmly gripped by the jaws.
Once adequate clamping pressure has been reached, the hammer is ready to
vibrate. Engage the "start" control. The exciter case and pile will begin vibrat-
ing.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 19 of 50, 1989,1992 Don C. Warrington
If driving, the combined weight of the hammer and pile will force the pile into
the ground. As the driving resistance increases, the drive pressure or amperage
will increase until it reaches the maximum power output of the power pack.
Any increased resistance may cause the hammer to slow down somewhat. The
hammer may be operated in this condition for short periods of time; however,
extended periods will cause the unit to overheat, causing possible damage to the
vibrator components. Also, if conditions warrant, the frequency of hydraulic
units can be varied by adjusting the engine speed.
If extracting, the crane must exert a net pull on the hammer-pile system. This
will cause the pile to move upward. When extracting, in general the best proce-
dure is to start the exciter without crane pull, allowing it to come up to speed,
loosen the soil and to drive a little. Once this loosening has taken place, extrac-
tion is easier. It is very important that the crane not exert an upward pull great-
er than the rated capacity of the exciter's suspension.
Shutdown: Once driving or extracting is complete, engage the "stop" control.
The exciter will stop in a couple of seconds. Make sure there is no net crane
pull on the hammer, and the exciter has stopped vibrating. Engage the "clamp
open" control, and remove the hammer from the pile. When you're ready to stop
for a longer time, also allow the engine to idle for five (5) minutes to cool, re-
duce engine speed to idle, and turn engine start switch to off.
Chapter V
MECHANISMS OF DRIVING BY VIBRATION AND IMPACT-VIBRATIONMECHANISMS OF DRIVING BY VIBRATION AND IMPACT-VIBRATION
§11 Classical Theories of Soil Response to Pile Vibration
As the name implies, vibratory hammers apply a vibratory, i.e., an alternating
and rapidly repetitive force, to drive piles. Now, when driving piles by impact, it
is necessary for the hammer to generate high forces to move the pile blow by
blow; on the other hand, vibratory hammers impart energy to the pile-soil sys-
tem continuously rather than incrementally. Impact drivers also impart their
motive force in one direction, namely down, which is where one wants the pile
to go. Vibrators, however, are inherently bidirectional in their force generation,
so either during driving or extraction half of the force is going the wrong way.
Yet vibrators can be effective for both operations. How can this be?
The key to solving this problem lies in the soil response to vibration. There are
three basic explanations that have been tendered to explain the mechanism of
vibratory driving; these are summarized as follows:
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 20 of 50, 1989,1992 Don C. Warrington
Thixotropy: Gumenskii and Komarov (1959) explain this process as follows: "By
thixotropy (from the Greek "thixis" -- shaking -- and "trope" -- change) of
dispersed systems in general, or of soils in particular, we mean their
liquefaction during jarring by some mechanical action (shaking, stirring,
etc.). Under such circumstances, at a constant temperature, there occurs
a transition from a gel to a sol, which, after a certain time, is again con-
verted to a gel. Thixotropy should thus be considered to involve two
aspects: liquefaction and solidification. These constitute a reversible
process, since it is repeated many times."
With this theory, when the soil is excited by vibration, the resistance is
reduced so that the system can either drop by its own weight or come out
of the ground from the pull of the crane. The pile is not actually forced
into the ground by the vibrating force but by the net applied static force on
the system. For driving, gravity acts to push the pile downward into the
soil; however, if the crane were to exert a net upward force on the system,
the pile moves upward. This enables a vibratory hammer to act as an
extractor, which is important in many applications. Important variables
for this theory are frequency, power, acceleration or dynamic force, and
velocity
Implicit in this explanation of soil response is the need for energy input.
What we are dealing with here is a chemical phenomenon; like others, it
needs energy input to make it work. With vibratory hammers this is
generally expressed as energy over time, or power. Inadequate power will
result in incomplete soil transformation and increased apparent soil resist-
ance.
System Amplitude: This concept is most succinctly stated by Erofeev et.al.
(1985): "Centrifugal force created by the vibration exciter with the turning
of the shafts with unbalanced loads, or eccentrics, attached to them cause
the pile to vibrate. The characteristics of these vibrations depend on the
static moment of the eccentrics, the frequency of the vibrations as deter-
mined by the angular velocity (ω or θ), the weight of the vibratory pile
driver-pile system, and the properties of the soil. The amplitude of the
system's vibrations is decisive for the insertion of the pile. At a low vibra-
tional amplitude, displacement of the soil with respect to the side surface
of the element being inserted does not exceed the limit of its elastic defor-
mation and the pile is not sunk into the ground. As the amplitude of the
vibrations increases, residual deformation of the soil occurs and the pile
begins to slip relative to the soil, i.e., it is sunk into the ground." This
principle, of course, is also applied to wave equation analysis of impact
driving, as no set of the pile is possible without exceeding the elastic limit,
or quake, of the soil. Important variables for this theory are frequency
and amplitude.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 21 of 50, 1989,1992 Don C. Warrington
Dynamic Force: This concept is based on the hypothesis that the force generat-
ed by the rotating eccentrics breaks the bond between the pile and the
soil, thus making vibratory driving (or extraction) possible. A general
adjunct to this hypothesis is the modeling of the soil resistance as being
dry frictional or Coulombic in nature. Starting with a version of Equation
(4) modified to include Coulombic soil resistance, Tseitlin et. al. (1987)
describe a mathematical model to compute vibratory penetration. In this
discussion, having made the preceding assumptions, they go on as fol-
lows: "Experimental research has established that the amplitude of the
vibrations Ag of the ground surrounding the pile is comparable to the
amplitude of the pile being sunk only during the initial stage in which the
pile vibrates together with the ground. As breakthrough progresses, the
ground vibrations diminish, while those of the pile increase; in the final
stage of breakthrough, the ratio of the amplitude of the pile's vibrations to
that of the ground vibrations reaches two to three orders of magnitude,
which also permits us to consider the ground surrounding the pile immo-
bile during the sinking process...Experimental data attesting that the
elastic component of lateral ground resistance is two orders of magnitude
less than the plastic component exemplify the fact that the elastic com-
ponent of lateral ground resistance is negligible during vibrational sinking
at high speeds. As far as the viscous component of ground resistance
during vibrational sinking is concerned, it is nonlinear in nature (i.e., it
has a soft characteristic)...and it changes little with increases in speed
even at low vibration speeds (5-10 cm/sec)." Important variables for this
theory are frequency and acceleration or dynamic force.
§12 Summation and Synthesis of Vibratory Driving Mechanisms
With these three models (and any other that might be proposed), it would seem
that the mechanism for vibratory pile driving is well understood, but the reality
is different. Without making a rigorous analysis of these methods, some attempt
to make sense of it all must be made and so a few observations are in order.
The whole object of vibratory pile driving is to sink or extract piling into soil,
and so the response of the soil to the vibration is the critical factor. However,
when we consider "soil response", it is easy to overlook the fact that piles inter-
face the soil in two ways, namely in shear (shaft friction) and compression (toe
bearing). Soils are not bound to respond to either static or dynamic loading in
the same way and in fact do not.
Vibratory hammers that are used for non-displacement piles generally have low
to moderate amplitudes and operating frequencies above 20 Hz. In the U.S. at
least, these machines make up the vast majority of the vibratory hammers.
When displacement piles (such as concrete piles) are driven with vibratory
hammers, frequencies around 10 Hz are more common along with much higher
amplitudes. This type of variation indicates that all three theories of vibratory
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 22 of 50, 1989,1992 Don C. Warrington
driving have application depending upon the type of pile and of course of soil.
In addition to the variation of drivers with piles, as a general rule vibratory
drivers are found to be most effective in cohesionless soils. This is probably true
because these soils are more likely to undergo thixotropic change. Since low
displacement piles have by definition less toe resistance, it seems that the com-
bination of low toe resistance and cohesionless soils is the ideal situation for
vibratory driving, and in these cases the thixtropic model (and perhaps the
dynamic force model) applies, although Gumenskii and Komarov (1959) showed
thixotropy to take place in clays routinely.
When soils become more cohesive, vibratory driving becomes less effective, but
it is also found that increasing the amplitude will aid the pile sinking consider-
ably. The reason for this probably relates to the toe resistance, whether it is
with low or high displacement piles. It is unlikely that the sucessive compres-
sion of the toe produces much thixotropy, especially in cohesive soils, and so
when toe resistance is elevated -- whether by a large toe area or with stiff, espe-
cially cohesive soils, or both -- the vibrator must resort to a different mode of
operation, in this case by picking up the entire system and forcing it down onto
the toe by the vibratory cycle (frequently referred to as a "chopping" mode).
This in effect makes the entire pile an impact ram, and in this case system
amplitude becomes very important, as is stroke with an impact hammer. High
system amplitudes allow more easily high velocities which make the impact
more effective.
Finally, one factor that does not appear in any of these models is that of fre-
quency, although it has been shown that soil response does vary with frequency.
(O'Neill, 1988)
We can see from these considerations that the differing explanations of vibra-
tory driving stem in reality from that fact that different piles and soils demand to
be driven differently. It is also likely that our understanding of the mechanisms
of vibratory driving and extraction and their application will improve as re-
search continues.
§13 Driving Mechanism of Impact-Vibration Machines
Impact-vibration hammers do not drive piling exactly like either impact or
vibratory hammers but in reality are a mixture of the two. The best way to
consider this is to look at in relation to pure vibratory driving.
As we have said above, vibratory driving is least effective when the toe resist-
ance is high. Impact-vibration hammers are more effective in these situations
because they can generate high peak forces to drive through these, much as a
high amplitude high velocity vibratory hammer can do. It is for this reason that
impact-vibration hammers are used extensively for concrete piles. They are
capable of delivering the driving forces necessary to overcome the high toe
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 23 of 50, 1989,1992 Don C. Warrington
resistance.
With relation to impact hammers, these hammers deliver a lower impact energy
per blow with more blows than a vibratory hammer can. In soils where elastic
compression is not a major problem, this should produce comparable results.
Impact vibration hammers produce some forces through the springs. In general,
these are not a major factor in impact-vibration driving, especially where the
frame is loaded down with deadweight to keep it on the pile. In such a case,
there is no transfer of alternating force to the pile. Bi-directional force with
impact-vibration machines is possible if the exciter is allowed to impact at both
the top and the bottom of its travel, and this can be helpful in both driving and
extraction.
Chapter VI
MATHEMATICAL DESCRIPTION OF VIBRATORY AND IMPACT-VIBRATION MATHEMATICAL DESCRIPTION OF VIBRATORY AND IMPACT-VIBRATION
MECHANICS AND DRIVING PERFORMANCEMECHANICS AND DRIVING PERFORMANCE
§14 Basics of Vibratory Mechanics
r
Center
Shafts
F
m
dyn
F
dyn
Figure 11 Vibratory Eccentric Configuration
A vibratory pile driver is a machine that installs piling into the ground by apply-
ing a rapidly alternating force to the
pile. This is generally accomplished
by rotating eccentric weights about
shafts. Each rotating eccentric pro-
duces a force acting in a single plane
and directed toward the centerline of
the shaft. Figure 11 shows the basic
setup for the rotating eccentric
weights used in most current vibra-
tory pile driving/extracting equip-
ment. The weights are set off center
of the axis of rotation by the eccentric arm.
Generally speaking, many of the traditionally measured quantities for vibratory
hammers such as amplitude, acceleration ratio, etc., are computed for the "free-
hanging" case, i.e., with only the mass of the system taken into account and no
soil resistance. For most conventional vibratory hammers, one can consider the
entire system a rigid mass. This is because the relatively low frequency vibra-
tions of most vibratory hammers do not bring the distributed mass and elasticity
of the system into play. By definition, with the sonic pile drivers the resonant
properties of the system become significant, and the analysis becomes more
complicated.
As the figure shows, the weights rotate about the center shaft with an angular
velocity w, given by the equation
ω = 2·π·θ..................................................................(1)
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 24 of 50, 1989,1992 Don C. Warrington
where ω = angular velocity of rotation, rad/sec
θ = frequency of vibrations, Hz = (Eccentric RPM)/60
For a rotating body, the force exerted on the center shaft is given by the equa-
tion
Fdyn = m r ω²/1000 .........................................................(2)
where Fdyn = dynamic force of eccentrics, kN
m = eccentric mass, kg
r = eccentric moment arm, m
If we define
K = m·r .................................................................(3)
where K = eccentric moment, kg-m
we can substitute to
Fdyn = K·ω²/1000...........................................................(4)
If only one eccentric is used, in one revolution a force will be exerted in all
directions, giving the system a good deal of lateral whip. To avoid this problem,
the eccentrics are paired so the lateral forces cancel each other, leaving us with
only axial force for the pile. Machines can also have several pairs of smaller,
identical eccentrics synchronized and obtain the same effect as with one larger
pair. Thus, the "m" term means the sum of all the eccentric weights, the eccen-
tric arm length for all being equal.
Without considering the effects of gravity, the equation of motion is
x" = 1000·Fdyn·sin(ω·t)/M...................................................(5)
where x" = instantaneous acceleration of system, m/sec²
The solution of this equation is
x = K·sin(ωt)/M ...........................................................(6)
where x = system displacement, m
In the process of integrating Equation (5), we can derive three very important
quantities. The first is the ratio of accelerations, or the peak acceleration during
a vibratory cycle; it is
n = Fdyn/Wdyn..............................................................(7)
where n, n1, n2 = ratio of maximum acceleration of system to acceleration due
to gravity, g's
Wdyn = vibrating weight of system, kN = g·M/1000
g = acceleration of gravity = 9.8 m/sec²
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 25 of 50, 1989,1992 Don C. Warrington
The second is the peak velocity, which is
vdyn = gn/ω................................................................(8)
where vdyn = peak dynamic velocity during the cycle, m/sec
These quantities are important because the power transmitted to the soil must
be done in an efficient manner from a high energy source through the pile-soil
interface to a low one in the soil. As the vibratory excitation is dynamic, it must
be done through these quantities. Minimum values for n have been established
from 1.5 to 9, but there is no consensus on this.
Finally, the maximum displacement is
xmax = K/M................................................................(9)
where xmax = maximum displacement of system (zero to peak), m
Since the acceleration, velocity, and displacement of the system solved from
Equation (5) are all sinusoidal with respect to time, these quantities are meas-
ured from the zero line of the sine wave. Customarily, the maximum cycle
displacement of the vibrator, called the amplitude, is measured from peak to
peak and is expressed as
A = 2xmax ............................................................... (10)
where A = amplitude of system (peak to peak), m
The instantaneous torque driving the eccentrics is
Tinst = (Fdyn/ω)²·sin(2ωt)/(2·M) ............................................ (11)
where T, Tinst, Tmax, Trms = motor torque, kJ
The maximum instantaneous torque is
Tmax = (Fdyn/ω)²/(2·M).................................................... (12)
Looking forward to the power requirements, normally one would use an root
mean square (rms) value to match an application to a motor, so
Trms = Tmax/2........................................................... (13)
From the torque the power is simple to compute, given by
N = ω·Trms .............................................................. (14)
where N = motor power, kW
Adequate power is essential for successful vibratory driving because, among
other reasons, maintenance of the vibratory frequency is impossible without it.
An underpowered machine will slow down and thus reduce its own driving
capability. Excess power, on the other hand, is pointless as the system will not
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 26 of 50, 1989,1992 Don C. Warrington
take any more power than it needs. This is one of the hardest things to under-
stand about vibratory systems; the problem is most succinctly stated by
Goncharevich and Frolov (1985):
The power which is required to operate the vibratory
machine in the given regime and the power which can
be transmitted by a vibrator of a specific type are deter-
mined by a whole complex of factors: vibrator paramet-
ers, machine characteristics, and the acting loads in the
machine. It is not possible to impart additional power
to the vibratory machine by simply increasing motor
output. Each vibratory machine consumes strictly
determined power, whose value is dependent on a
whole set of factors acting in the vibratory machine-
vibration exciter-load system.
The one thing over which the machine operator has most control that can in-
fluence power requirements is the static force applied to the system, whether
with bias weight or downcrowding in driving or additional crane force in pull-
ing.
§15 Basics of Drivability and Capacity Prediction For Vibratory Hammers
The ability of vibratory machines to drive piling is well demonstrated; however,
one major obstacle to the expanded use of these machines is the lack of an
accepted method to relate the driving performance of a hammer/pile/soil system
to either the resistance of the soil to driving or the static capacity of the pile.
This section will discuss some of the methods developed in the past to determine
the drivability of vibratory hammers and ultimately the bearing capacity of the
piles driven.
The methods presented below date from the very earliest application of vibra-
tory technology to pile driving to the present; they take a wide variety of ap-
proaches and will give a wide variety of results. For convenience, we will break
down these methods into four groups:
1)Parametric methods: Certain characteristics are tested against some kind of
standard to determine drivability.
2)Energy methods: Drivability is determined based on the energy flow through
the system, along with other considerations.
3)Methods from Laboratory and Model Tests: These methods are derived from
correlations gathered from tests in a laboratory setting, usually driving a pile
through a soil tank.
4)Time Dependent Nonlinear Methods: These seek to apply numerical integra-
tion techniques to the direct solution of the equation(s) of motion of the vibrat-
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 27 of 50, 1989,1992 Don C. Warrington
ing system. These include the wave equation techniques popular with impact
hammers.
One important observation at this point is that, in general, vibrated piles have
lower bearing capacity than impact driven ones. This is because impact driving
produces soil compacting at the toe that vibrating does not.
Most of the formulae below are reproduced from their sources; however, when
necessary they have been altered into a uniform units (SI) and notation system.
§16 Parametric Methods
Tünkers Dynamic Force Method: Basically, this method employs the formula
Fdyn > s·As.............................................................. (15)
where s = Unit Soil Shaft Resistance, kPa
As = Shaft Area of soil, m²
Values for the factor r are given in Table 2. The formula is only applicable when
xmax > 2.38mm. To compute the shaft area for sheet piling, this method employs
the following computation:
As = 2.8·l·dinter........................................................... (16)
where l = Pile Length, m
dinter = Width of Sheet piling, m (from interlock to interlock).
Table 2
Values of σ for Tünkers Method
SPT Value, blows/30cm Soil
Resistance,
kPa
Cohesionless
Soil
Cohesive Soil σ
0-5
0-2
9.86
5-10
2-5
11.87
10-20 5-10 12.83
20-30 10-20 14.84
30-40
20-30
15.80
40+
30+
16.76
Beta Method: A given vibratory hammer is suitable for driving a given pile when
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 28 of 50, 1989,1992 Don C. Warrington
Fdyn+Wdyn+Wst > βo·Rso+βi·Rsi+βt·Rt...................................... (17)
where Wst = Non-Vibrating Weight of System, kN
β = Beta Factor for Soil Resistance (general)
βi = Beta Factor for Soil Resistance (outside shaft)
βo = Beta Factor for Soil Resistance (inside shaft)
βt = Beta Factor for Soil Resistance (toe)
Rsi = Inside Pile Shaft Soil Resistance,kN
Rso = Outside Pile Shaft Soil Resistance, kN
Rt = Pile Toe Soil Resistance, kN.
Suggested values for β are given in Table 3. For extraction, this formula is
altered to read
Fdyn+Fext-Wdyn-Wst > βo·Rso+βi·Rsi+βt·Rt................................... (18)
where Fext = Extraction Force of Crane, kN.
Table 3
Values of βn for Beta Method
Type of Soil β
Round Coarse Sand 0.10
Soft Loam/Marl, Soft Loess,
Stiff Cliff 0.12
Round Medium Sand, Round
Gravel 0.15
Fine Angular Gravel, Angular
Loam, Angular Loess 0.18
Round Fine Sand 0.20
Angular Sand, Coarse Gravel 0.25
Angular/Dry Fine Sand 0.35
Marl, Stiff/Very Stiff Clay 0.40
where n = i, o, or t depending upon
relative position of pile and soil in
question.
Table 4
Values of Pile Toe Weight Pressure po for
Savinov and Luskin Method (For Saturated
Sandy and Loose-Clayey Soils)
Type of Pile Pressure
, kPa
Small Diameter Steel
Pipe and other Piles
w/At<150 cm² 150-300
Closed End Pipe Piles,
At<800 cm² 400-500
Square and
Rectangular
Reinforced Concrete
Piles, At<2000 cm²
600-800
Savinov and Luskin Method: This method was developed in Russia by two of the
pioneers in the development of vibratory pile driving equipment. Presented
below is a reformulated version, done for simplicity and clarity. The steps are as
follows:
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 29 of 50, 1989,1992 Don C. Warrington
1)Computation of the required minimum dynamic weight: To insure sufficient
weight for pile sinking, the minimum dynamic weight of the system is computed
by the formula
Wdyn > po·At............................................................. (19)
where At = Toe Area of Pile, m²
po = Toe Pressure of System, kPa (as given in Table 4)
Although the method calls for the weight computed above to be dynamic, there
is also the possibility of having part of this weight to be static.
2)Determination of the soil resistance: For vibration purposes, the soil resist-
ance is determined by the following formula:
i=k
Fcr = Z · si·li..................................(Piling in general -- 20a)
i=1
i=k
Fcr = si·li......................................... (Sheet Piling -- 20b)
i=1
where Fcr = Critical Force for Driving, kN
Z = Pile Perimeter, m
si = Soil Element Shaft Resistance, kPa or kN/m
li = Pile Element Length, m
The length of the pile is first divided into segments of length li, then the soil
resistance s for each segment is taken from Table 5, depending upon the type of
soil in the given segment.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 30 of 50, 1989,1992 Don C. Warrington
Table 5
Soil Resistance for Savinov and Luskin Method
Type of Soil and Pile σ
For Piles,
kPa For Sheets,
kN/m
1)Saturated Sandy and Visco-Plastic Clay Soils
Steel Tubes 6
Reinforced Concrete Piles 7
Open-Ended Pipe Piles 5
Sheet Piles, Light (Heavy) Sections 12 (14)
2)The same as (1), but with Interlayers of Compact Clay or Gravelly Soils
Steel Tubes 8
Reinforced Concrete Piles 10
Open-Ended Pipe Piles 7
Sheet Piles, Light (Heavy) Sections 17 (20)
3)Stiff Plastic Clay Soils
Steel Tubes 15
Reinforced Concrete Piles 18
Open-Ended Pipe Piles 10
Sheet Piles, Light (Heavy) Sections 20 (25)
4)Semi-Hard and Hard Clay Soils
Steel Tubes 25
Reinforced Concrete Piles 30
Open-Ended Pipe Piles 20
Sheet Piles, Light (Heavy) Sections 40 (50)
3)Computation of the dynamic force of the eccentrics: The dynamic force is first
computed to meet the following two criterion:
a)Soil resistance factor: The dynamic force should be greater should be greater
than the soil resistance, as expressed by the formula
Fdyn > ·Fcr÷ψ........................................................... (21)
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 31 of 50, 1989,1992 Don C. Warrington
where ψ = Pile Factor (0.8 for concrete piling and 1 for all other piling.)
= Soil Resilience Coefficient (should be between 0.6 and 0.8 for
vibration frequencies between 5 and 10 Hz and 1 for all other frequen-
cies.)
b)System acceleration factor: The peak cycle acceleration should fall within
values such as
n1 < Fdyn÷Wdyn < n2...................................................... (22)
Table 6
Values for Ratio of Accelerations "n" for Savinov and Luskin
Method
Type of Pile Minimum Ratio
of Accelerations
n1
Maximum Ratio
of
Accelerations n2
Steel Sheet Piling 2.00 6.67
Light Piles 1.67 3.33
Heavy and Pipe
Piles 1.00 2.50
Values for n1 and n2 are given in Table 6. The method seems to favor Equation
(22) over (21) in case of
conflict.
4)Compute the necessary
frequency to insure a
minimum peak vibration
velocity by the equation
ω = 1000·Fdyn/(vdyn·M) (23)
Velocity vdyn should fall
between 0.5 and 0.8 m/sec.
5)Compute the eccentric
moment using rigid body
vibratory mechanics by the
equation
K = 1000·Fdyn/ω²......................................................... (24)
6)Check for adequate amplitude against the recommended values for xmax as
shown in Table 7. Amplitude is computed using the equation
xmax = 1000·K·ψ/M....................................................... (25)
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 32 of 50, 1989,1992 Don C. Warrington
Table 7
Amplitude Requirements for Savinov and Luskin Method
Frequency, Hz 5-12 Hz 13-17 Hz 18-25 Hz
Type of Pile and Soil Half Amplitude, mm
Steel Sheet Piling, Open Ended Pipe
Piles, and Other Piles with At < 150 cm²
Sandy Soils 8-10 4-6
Clayey Soil 10-12 6-8
Closed End Steel Pipe Piles, At < 800 cm²
Sandy Soil 10-12 6-8
Clayey Soil 12-15 8-10
Reinforced Concrete Piles, Square or
Rectangular Section, At < 2000 cm²
Sandy Soil 12-15
Clayey Soil 15-20
Reinforced Concrete Cylinder Piles of
Large Diameter, Driven with Soil Plug
Removed
Sandy Soil 6-10 4-6
Clayey Soil 8-12 6-10
7)Compute the power of the driving motors: This is done using the formula
N = Kθ3(3.2×10-6D+.079K/M) ............................................ (26)
where D = Diameter of Bearing Race, mm
Equation (26) was developed with the following assumptions:
a)Efficiency of the power transfer from motor to vibration exciter is 90%.
b)Coefficient of rolling friction in the bearings is 0.1%.
c)Of the power actually sent into the soil, 15% of it is lost in the soil mass.
The Savinov and Luskin method is unique in that it uses parameters of empirical
and theoretical derivation (ratio of accelerations, dynamic velocity, soil resist-
ance, soil and pile material factors, and pile toe pressure) and combines their
use using standard, free-hanging, rigid-body vibratory mechanics. The result is
a hammer that is optimized for the pile to be driven. This method is iterative; it
may require several cycles to get the resulting hammer to fit the parameters to
the best extent possible.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 33 of 50, 1989,1992 Don C. Warrington
Evaluation: The main advantage of the parametric methods is their relative
simplicity of formulation and computation. The parametric methods make
integrating experience-developed factors into the calculation very simple as
well.
There are two main disadvantages of parametric methods. The first one is that
none of the methods either adequately take into account all of the variables
present in the vibratory installation of piles or account for the interaction bet-
ween these variables. For instance, except for the Savinov and Luskin method,
none of the methods take into account either the effect of power availability and
input into the system or of frequency. Also none can be considered really valid
at frequencies higher than 25-30 Hz. The second shortcoming of parametric
methods is the lack of any consideration of installation velocity either as an
input variable or as a result. This is important for two reasons; first, computing
velocities for a number of system combinations is the only comprehensive way
to compare different systems; second, any scheme to use vibratory drivers with
bearing piles will probably use installation velocity as an acceptance criterion,
much as the blows per meter (foot) are used now with impact hammers.
§17 Energy Methods
Energy methods to compute drivability are based on the assumption that, during
most vibratory driving, the power put into the system by the vibrator equals the
power taken out by the soil resistance. Thus energy methods are steady state
methods, and do not take into account transient effects. There are two energy
and power sources of a system: 1)the driving motor of the vibrator, 2)the poten-
tial energy of the system falling through the gravity field. The sink or destina-
tion for this energy is the resistance of the pile acting against the sinking pile.
Mathematically, this energy and power flow is expressed by the formula
Ru·Vsys = N+(Wdyn+Wst)·Vsys ............................................. (27)
This equation can be reformulated in two ways; first, to compute penetration
velocity,
Vsys = N,(Ru-Wdyn-Wst)................................................... (28)
and for bearing capacity of the pile,
Ru = Wdyn+Wst+N,Vsys................................................... (29)
where Ru = Soil Resistance, kN
Vsys = Pile Penetration Velocity, m/sec
These are ideal equations; in practice, these methods add factors to account for
actual conditions.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 34 of 50, 1989,1992 Don C. Warrington
Davisson Method: This formula was proposed to predict the bearing capacity of
piles driven with the Bodine BRD-1000 resonant vibratory pile driver. Making
an analogy with the dynamic formulae, in the place of impact a full cycle of the
eccentrics is considered as the time of energy transfer from hammer system to
soil; thus, the loss factor is based on a per cycle basis. Generalizing, the formula
is
Ru = (N+(Wdyn+Wst)·Vsys)/(Vsys+θ·Sl/1000)................................ (30)
where Sl = Soil Loss Factor, mm/cycle
and for penetration velocity, we can rearrange it to read
Vsys = (N-Ru·θ·Sl/1000)/(Ru-Wdyn-Wst)..................................... (31)
Table 8
Loss Factors for Davisson Method
Soil @ Pile Tip Loss Factor Sl,
mm/cycle*
Closed-End
Pipe Pile H-Beam
Loose Silt, Sand, or
Gravel 0.24 -0.21
Medium Dense Sand, or
Sand and Gravel 0.76 0.76
Dense Sand or Sand
and Gravel 2.44 2.13
*Values developed for Bodine BRD-1000
Resonant Driver. Formula not applicable in rock.
Values for Sl are given in Table 8. The formula is mainly intended for field use,
and so all of the variables are
taken from actual data.
Snip/Soviet Methods: These
are placed with the energy
methods because of their
format and their involvement
of horsepower, deadweight,
and (indirectly) penetration
velocity. They were developed
for precast concrete cylinder
pile. They are
Ru = (λ-
30000·Vsys/(Aoθ))·(245·N/(Aoθ)
+Wdyn+Wst)/F...........(32a)
and
Ru =
(245·λ·N/(Ao·θ)+Wdyn+Wst)/F..
(32b)
where λ = Soil Coefficient
F = factor of safety (generally F=2)
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 35 of 50, 1989,1992 Don C. Warrington
Table 9
Soil Coefficient for Snip/Soviet Formula
Soil Type k
Saturated Sand 4.0-7.5
Moist Sand 3.0-4.5
Dry Sand 2.5-4.0
Sand Clay 2.5-5.0
Silty Clay 2.2-4.5
Clay 2.0-4.5
Equation (32a) is for penetration velocities of 0.5-1.67 mm/sec, and (32b) for
0.05-0.5 mm/sec. Values for l vary with
soil conditions and are given in Table 9.
Evaluation: Energy methods have three
main advantages. They are inherently
simple. They are able to incorporate many
factors into the analysis. They give as a
result a penetration velocity (or conversely
a bearing capacity), which allows mea-
ningful comparison of different systems
with each other.
The main disadvantage of energy methods
lies in one of their advantages, namely
their simplicity. They may not take into
account all of the necessary factors in a meaningful way. This is in part due to
their lack of broad field correlation. The Davisson method has extensive field
documentation, but it is only been done for the Bodine hammer, which operates
at frequencies well above most any other vibratory pile driving machine. Con-
versely, the Snip/Soviet method is well tested for penetration velocities that
would be considered low in the U.S. These methods need more field develop-
ment under a wide variety of conditions if they are to reach their full potential.
§18 Methods from Laboratory and Model Tests
The use of laboratory and model testing to establish the drivability of vibrated
piling represents an attempt to establish a reliable correlation based on an
actual physical situation but in a controlled environment. Generally it involves
setting up a tank full of soil and driving the piling through the tank, either
horizontally or vertically. The various parameters of the system can then be
varied to produce data for correlation purposes.
Bernhard's Method: To compute the static bearing capacity, the method employs
the following formula:
Ru = f·N·l/(Vsys·lsoil)...................................................... (33)
where lsoil = Length of Soil Penetration by Pile, m
f = Soil Loss factor (suggested value is 0.1)
The tests that established the formula were run in a frequency range of 50-5250
Hz.
Schmid and Hill's Formula: They propose from statistical data reduction that
the penetration velocity of the pile can be estimated by the formula
Vsys = 0.417·g·n0.75·((Wst+Wdyn),Ru+0.0036·n-0.018)/θ...................... (34)
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 36 of 50, 1989,1992 Don C. Warrington
The test pile was driven through sand exclusively. The test setup limited the
frequency to a maximum of 30 Hz. Schmid went on to develop another method,
his Toe Impulse Formula, which is
Ru = α·(Wdyn+Wst)/(θ•√(2·Vsys,(θ·n'·g))) ................................... (35)
where a = a coefficient, taken to be 0.67
n' = acceleration in excess of the minimum acceleration to effect
driving, g's
O'Neill's Formula: This formula came from tests run on a vibrator driving a
miniature pile in a sand tank. It is
Ru = 0.050·N'/(Vsys·(σ'h/92.8-0.486)·(1.96·Dr-1.11)·(1.228-0.19·d10)) .......... (36)
where s'h = horizontal effective stress, kPa
Dr = relative density
d10 = grain size, mm
N' = power actually delivered to the pile top, kW
The theoretical power the vibrator generates can be computed by the equation
N = θ·(4000·Wst+2·K·ω²·(1+θ²/(θ²+θn²)))·(K·θ²/(1000·M·(θ²+θn²))) .......... (37)
where θn = natural frequency of suspension with respect to the vibrator mass,
Hz
and this is related to the power actually delivered to the pile top by the formula
N' = (0.25+0.063·n)·N ................................................... (38)
The peak acceleration can be computed by the formula
n = (3.54-2.186·Dr)·(8.99+2.76·d10)·((39.37·Vsys)(1.71-s'h/85.1))................. (39)
Evaluation: The advantage of laboratory and model test formulas are that the
results they give have their root data taken from a controlled physical environ-
ment. The various parameters of the system can thus be taken into account in a
physically realistic and truly interactive fashion.
The main weakness of these laboratory derived formulae is that the conditions
produced in the laboratory may not include all that is actually experienced in
actual vibratory pile driving. They should be used only when the original condi-
tions under which they were derived are present in the field. Also, none of the
formulae above is comprehensive in its parameter inclusion. Nevertheless,
because of their virtues, laboratory and model tests remain an important consti-
tuent of vibratory pile driving research.
§19 Time Dependent Nonlinear Methods
The newest method to be applied to vibratory installation of piling is that of time
dependent nonlinear methods. These methods seek to actually solve the equa-
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 37 of 50, 1989,1992 Don C. Warrington
tions of motion of the vibratory system through numerical integration. These
methods divide themselves into two categories: 1)methods which consider the
distributed mass and elasticity of the system (wave equation techniques), and
2)those which don't (rigid body techniques).
VIBEWAVE Method: This involves using a modified version of the TTI program.
This model uses a finite difference mass-spring-dashpot model which is solved
using a modified version of Euler's Method.
TNOWAVE Method: This again involves the modification of a wave equation
analyzer for use with vibratory hammers. TNOWAVE uses the method of char-
acteristics to solve the wave equation.
Piecewise Integration Techniques: These are rigid body techniques which are
applied to the system. The pieces are determined by changes in the variables,
especially the reversal of the soil frictional force. Since the equations for these
techniques can be formulated dimensionlessly, parametric studies can be per-
formed using these techniques. In addition to solving longitudinal vibratory
motion, these have been applied for longitudinal-rotational and impact-vibra-
tional type drivers.
VIBDRIVE Method: This was developed by the author for the VIBDRIVE analy-
sis program. It is a rigid body technique that uses a variation of Euler's tech-
nique (different from TTI) to solve the equations of motion. A Coulombic soil
model is used for the shaft resistance and a constant resistance plug model is
used for the toe.
Evaluation: Assuming that they are properly set up, time dependent non-linear
methods are the most complete method available to analyze the vibratory in-
stallation and extraction of piles. They can take into account all system varia-
bles through their thorough modeling of the system. This is especially import-
ant with the wave equation methods at higher frequencies, as both distributed
mass and elasticity in the system become more important.
The main weakness of these methods is the accuracy of the constituent compon-
ents of the model. These must be both thoroughly understood and accurately
simulated for meaningful results. These conditions have not been met yet; the
popular Smith model for soil response cannot be applied without modification to
vibratory soil excitation.
§20 Methods for Impact-Vibration Hammers
Because of their construction and operation, impact-vibration hammers are by
their nature more complex to analyze than their vibratory conterparts, and so
create more analytical problems. Most of the information given below is taken
fron Tseitlin et. al. (1987). Before we get into the actual calculations, we need to
define a few important, dimensionsless quantities.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 38 of 50, 1989,1992 Don C. Warrington
The first thing to note -- and in reality it is one of the first things that anyone
noted about these machines -- is that the exciter does not impact the anvil with
every blow. Tsaplin (1953) first observed this, and defined the ratio of the
frequency of rotations to the frequency of impacts. This is mathematically
stated as
i = θ/θi............................................................... (40)
where i = ratio of imacts to exciter frequency
θi = number of impacts per second
θ = frequency of vibrations, Hz
With most impact-vibration machines, the exciter is mounted in the frame with
springs, and so we can define define the ratio of the natural frequency of the
head/spring system to the impact frequency, which is
ξ1 = θn/θ............................................................... (41)
where ξ1 = ratio of natural frequency of exciter to frequency of impacts
θn = natural frequency of the exciter, Hz
We also need to define two force ratios; they are
f = F/Fdyn ............................................................... (42)
and
γ = R/Fdyn ............................................................... (43)
where f = ratio of shaft soil resistance to dynamic force of exciter
F = shaft soil resistance, kN
γ = ratio of toe soil resistance to dynamic force of exciter
R = toe soil resistance, kN
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 39 of 50, 1989,1992 Don C. Warrington
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
sin
1
Region 1
Region 2
Region 3
Figure 12 Regions of Impact-
Vibration Driving (after Tseitlin et.
al. (1987))
Finally, we need to set the angular operational parameter a'; generally, it should
range from 17½° to 30°.
Having set all of these parameters, we need to
first determine if we are in a region where
impact-vibrational action is taking place.
Looking at Figure 12, we see three regions
where impact-vibrational action is possible.
Taking the values for α' and ξ1, we determine
which region we are actually in. Impact-vibra-
tional action is possible if the sum of f and γ is
greater than 8 for Region 1, greater than 4 for
Region 2, and greater than 2 for Region 3.
This having been determined, a dimensionless
velocity for the exciter can be defined by the
equation
y'1 = 1.204 + 6.841x1 -6.161x1² + (4.357 - 21.215x1 + 16.203x1²)·sinα' - (6.188 -
15.434x1 + 10.616x1²)·sin²α'.............................................. (44)
where y'1 = dimensionless velocity
The actual impact velocity can be computed by the equation
vimpact = ω·K/(m1·y'1)..................................................... (45)
where vimpact = impact velocity, m/sec
m1 = mass of exciter, kg
The dimensionless impact displacement (pile set) is given by the equation
yn = (0.137-0.02·(f+γ)-0.0009·(f+γ)²)·y'1................................... (46)
where yn = dimensionless displacement
and the actual set is determined by the equation
xpl = K/(m1·yn).......................................................... (47)
where xpl = pile set, m.
In order for the pile to be moving, the pile must meet minimum a minimum
displacement criterion given by the equation
Dl < 1000·xpl ..............................................................(48)
where Dl = Perkov-Shaevich Criterion, given in Table 10, mm.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 40 of 50, 1989,1992 Don C. Warrington
Table 10
Perkov-Shaevich Criteria for Impact-Vibration Hammers
Soil Type Minimum
Value, mm
Oversaturated Sands of Medium Corseness and
Compactness 1.6
Saturated Sands of Medium Corseness and Compactness 2.2
Macroporous Sandy Loams of a hard constituency 2.8
Loams of stiff-plastic constituency 3.2
Undersaturated Sands of Medium Corseness and
Compactness 4.6
The power consumed by the machine is given by the equation
N = Kθ·(8·(2.808 - 3.04·sinα' - 0.0125·(f +γ))· (0.5/ξ1)0.12· (d/4)0.752 + 3.22·10-
4·θ²·D)/100 .............................................................. (49)
This formula assumes that the transmission efficiency of the motor to the vibra-
tor is 90% and that the coefficient of friction of the bearings is 0.1%.
CONCLUSIONCONCLUSION
Vibratory and impact-vibration hammers have proven themselves a versatile tool
to install and extract many kinds of piling. The former are limited principally by
very stiff soil conditions where impact is required and a lack of an accepted
method of determining the drivability and bearing capacity of the piles they
drive. The latter are limited mainly by mechanical design considerations. These
will be addressed as the technology progresses and the versatility of this equip-
ment will continue to be enhanced.
REFERENCES AND FURTHER READINGREFERENCES AND FURTHER READING
ANDERSON, R.D. (1970) "Foster Vibrator." Proceedings of the Conference of
Design and Installatin of Pile Foundations and Cellular Structures, Lehigh
University, Bethlehem, PA, pp. 241-255
AYRE, R.S. (1956) "Experiments on Vibratory Cutting of Soils." Highway Re-
search Board Proceedings, Vol. 35, pp. 714-724.
AYRE, R.S., and KONDNER, R.L. (1958) "Cutting and Penetration of Soils Under
Vibratory Loading: A Progress Report." Highway Research Board Proceedings,
Vol. 37, pp. 506-516.
BARKAN, D.D. (1948) Dynamics of Bases and Foundations. State Press for
Literature on Machine Construction, Moscow, Russia.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 41 of 50, 1989,1992 Don C. Warrington
BARKAN, D.D. (1957) "Foundation Enginering and Drilling by the Vibration
Method." Proceedings of the Fourth International Conference on Soil Mechanics
and Foundations Engineering, Vol. II, London, pp. 3-7.
BARKAN, D.D. (1959) Vibrometod v Ctroitelstve (Vibratory Methods in Con-
struction). Gosstroiizdat, Moscow, pp. 27-29.
BELOFF, W.R. (1987) "Vibratory Hammer Study Field Measurements." Report
prepared by Goldberg-Zoino & Associates, Inc. for the Deep Foundations Insti-
tute. January 1987. File No. B-7946.
BERNHARD, R.K. (1956) "Static and Dynamic Soil Compaction." Highway
Research Board Proceedings, Vol. 31, pp. 5563-592
BERNHARD, R.K. (1968) "Pile-Soil Interactions During Vibro-Pile-Driving,"
Journal of Materials, ASTM, Vol. 3 No. 1, March, pp. 178-209.
BIELEFELD, M.W., and MIDDENDORP, P. (1992) "Improved Pile Driving Pre-
duction for Impact Hammers and Vibratory Hammers, " Proceedings of the
Fourth International Conference of the Application of Stress Wave Theory to
Piles, pp. 395-399.
BILLET, P., and SIFFERT, J.G. (1985) "Détermination Expérimentale du Frotte-
ment Latéral en Vibrofonçage." (Experimental Determination of Shaft Friction
during Vibrodriving). Proceedings of the International Symposium on Pene-
trability and Drivability of Piles, International Society for Soil Mechanics and
Foundation Engineering, pp. 89-92.
BILLET, P., and SIFFERT, J.G. (1989) "Soil-Sheet Piling Interaction in Vibro-
Piling." Journal of Geotechnical Engineering, Vol. 115, No. 8, August, pp. 1085-
1101.
BLEKHMAN, I.I. (1954) "Examining the Process of Vibratory Driving of Piles
and Sheet Piles." Inzhener. Sbornik, USSR Academy of Sciences 19, pp. 55-64.
BOGGS, E.W. (1954) "Vibrating Driver Successful for Sheetpile Cells," Civil
Engineering, Vol 34, No. 4, April, pp. 58-60
BRIAUD, J.-L., COYLE, H.M, and TUCKER, L.M. (1990) "Axial Response of
Three Vibratory and Three Impact Driven H-Piles in Sand," Presented at the
69th Annual Meeting of the Transportation Research Board, Washington, DC, 7-
11 January 1990.
CATOIRE, B. (1963) "Théorie Soviétique du Fonçage des Pieux," Annales des
Ponts et Chaussées, Vol. 133, No. 1, January-February, pp. 63-68.
CHUA, K.M., GARDNER, S., and LOWERY, L.L. (1987) "Wave Equation Analysis
of a Vibratory Hammer-Driven Pile." Proceedings of the Nineteenth Annual
Offshore Technology Conference, Dallas, TX. OTC 5396, pp. 339-345.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 42 of 50, 1989,1992 Don C. Warrington
CIVIL ENGINEERING (1961) "Sonic Pile Driver Shows Great Promise," Civil
Engineering, Vol 31, No. 12, December 1961, p. 52.
DANCE, D.R. and RIDER, D.J. (1987) "Resonant Pile Driving." Presented at the
Twelfth Annual Meeting of the Deep Foundations Institute, Hamilton, Ontario,
Canada, 14-16 October 1987.
DAVISSON, M.T. (1965) "Estimating Resonant Frequencies for Pile Driven with
the BRD," October 19, 7 p.
DAVISSON, M.T. (1970) "BRD Vibratory Driving Formula." Foundation Facts,
Vol. VI No. 1.
DONDELINGER, M., and SOMMERFIELD, W.J. (1989) "The World in Steel
Sheet Piling." Pile Buck, First August Issue 1989, pp. 6A-23A.
EASTWOOD, W. (1955) "Model Investigations Concerned with Driving Piles by
Vibration." Civil Engineering and Public Works Review, Vol. 50, No 584 (Febru-
ary), pp. 189-191.
EL-NAGGAR, M.H., and NOVAK, M. (1994) "Nonlinear Axial Interaction in Pile
Dynamics." Journal of Geotechnical Engineering, Vol. 120, No. 4, April 1994, pp.
678-696.
ENGINEERING NEWS-RECORD (1959) "Soviet 'Shakedown' Russian Reports
Use of Vibrations to Drive Piles," Engineering News-Record, Vol. 163, No 23,
June 11, p. 28
ENGINEERING NEWS-RECORD (1961) "Sonics Drive a Pile 71 Ft. While Steam
Drives Another 3 In.," Engineering News-Record, Vol 167, No 19, September 13,
pp. 24-16.
ENGINEERING NEWS-RECORD (1962) "Vibratory Piledriver is Fast," Engineer-
ing News-Record, Vol 169, No. 11, September 13, p. 49.
ENGINEERING NEWS-RECORD (1964a) "Sonic Piledriver Takes Test as Fast,
Soft-Ground Tunneler," Engineering News Record, Vol 172, No. 2, January 9,
pp. 16-17.
ENGINEERING NEWS-RECORD (1964b) "Sonic Driver Pulls for an Economical
Job," Engineering News Record, Vol 173, No. 20, November 12, pp. 99, 102.
EROFEEV, L.V. (1966) Vibratsionnye I Vibroydarnye Mashiny Dlya Pogruzhe-
niya Svai (Vibration and Impact-Vibration machines for driving piles). NIIinf-
stroidorkommunash, Moscow, p. 43.
EROFEEV, L.V. (1968) Issledovanie Dvykhmassnogo Vibromolota (Study of
Dual Mass Vibrating Hammer) VNIIstroidormash Scientific Work #40, Moscow,
pp. 43-53.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 43 of 50, 1989,1992 Don C. Warrington
EROFEEV, L.V., SMORODINOV, M.I., FEDOROV, B.S., VYAZOVIKII, V.N., and
VILLUMSEN, V.V. (1985) Vfibys B J,jhelfybt Lkz Ecnhjqdf Jcyjdfybq B Aeylfv-
tynjd (Machines and Equipment for the Installation of Shallow and Deep Foun-
dation). Second Edition, Mashinostrenie, Moscow, pp. 95-111.
EROFEEV, L.V. and TROYANOVSKAYA, G.A. (1986) Teoriya I Raschet Nago-
lovnikov Svainykh Molotov (Theory and Calculation of the Dual Mass Vibrating
Hammer) VNIIstroidormash Scientific Work #7, Moscow, pp. 23-31.
EROFEEV, L.V., and WARRINGTON, D.C. (1991) "Development and Improve-
ment of Impact-Vibration Pile Driving Equipment in the USSR." Pile Buck,
Jupiter, FL, First May Issue, 1991
FLOYD, D., and ALDINGER, P.B. (1990) "Load Testing of Steel Sheet Piling
Driven with a Vibratory Hammer," Presented at the 69th Annual Meeting of the
Transportation Research Board, Washington, DC, 7-11 January 1990.
GARDNER, S. (1987) "Analysis of Vibratory Driven Pile." Naval Civil Engineer-
ing Laboratory Technical Note N-1779, Port Hueneme, CA.
GARRETT, R.E. (1988) "New Vibratory Hammer Proves Ideal for Aluminium
Sheeting." Pile Buck, Jupiter, FL, Second March Issue 1988, pp. 10-14.
GHAHARMANI, A. (1967) "Vibratory Pile Driving Ultimate Penetration and
Bearing Capacity," Ph.D. Thesis, Princeton University, Princeton, NJ.
GOLOVACHEV, A.S. (1964) Puti Povysheniya Effektivnocti Cvainykh Vibropo-
gruzhatelei v Transportnom Ctroitelstve (Ways of increasing the efficiency of
vibration pile drivers in transport construction). TsINTIAM OS-U, pp. 63-65.
GONCHAREVICH, I.F., and FROLOV, K.V. (1981) Ntjhbz Db,hfncbjyyjb Nt[ybrs B
Nt[yjkjubq. (Theory of Vibratory Technology.) Nauka, Moscow.
GREEN MOUNTAINEEER (1963) "Guild Driver Sonically at Montpelier," Green
Mountaineer, New England Telephon and Telegraph Company, October, p. 2.
GRIGGS, JR., F.E. (1967) "The Pile Problem with Special Emphasis on the Vibra-
tory Placement Technique." Doctoral Engineering Thesis, Renssalear Polytechi-
nic Institute, Order No. 68-823, 113p.
GRYNKEWISZ, F.M., BELOFF, W.R., and KIRK, T. (1991) "A Case Study Sup-
porting The Need For A Rational Method For Design And Installation Of Vibra-
tory Driven Piles." Presented at the Sixteenth Annual Members' Conference of
the Deep Foundations Institute, Chicago, IL, 7-9 October 1991.
GUMENSKII, B.M., and KOMAROV, N.S. (1959) Db,hj,ehtybt Uheynjd (Soil Drill-
ing By Vibration). Ministry of Municipal Services of the RSFSR, Moscow.2
2This work has an enormous bibliography of its own, containing over one hundred entries. Since
most of the works are in Russian and may no longer be available, only the most important works
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 44 of 50, 1989,1992 Don C. Warrington
HEJAZI, H.A. (1963) "The Influence of Forced Longitudinal Vibration on Rods
Penetrating Soils," Ph.D. Thesis, Ohio State University, Columbus, OH.
HIGHWAY RESEARCH BOARD (1960) "Soil and Foundation Engineering in the
Union of Soviet Socialist Republics, " Highway Research Board, Special Report
60 pp. 16, 17, 21, 41-43, 72-79.
HILL, H.T. (1966) "Frictional Resistance in Vibratory Pile Driving." Ph.D. Thesis,
Princeton University, Order Number 67-5727, 127p.
HILL, H.T., and SCHMID, W.E. (1967) "A Rational Dynamic Equation for Vibro-
Driven Friction Piles in Sand." Proceedings of the International Symposium on
Wave Propagatin and Dynamic Properties of Earth Materials, 23-25 August,
New Mexico, pp. 349-359.
HIRSCH, T.J., CARR, L. and LOWERY, L.L., Jr. (1976) "Pile Driving Analysis -
Wave Equation User's Manual, TTI Program." Federal Highway Administration
Project FWHA-IP-76-13 (4 vols.)
HUCK, R.W., and HALL, J.R. (1971) "Resonant Driving in Permafrost."
Foundation Facts, Vol. 7, No. 3, pp. 54-57.
IARROBINO, A.V. (1962) "Placing Piles by Vibration." Military Engineer, Vol. 54,
No. 357, January-February 1962, pp. 7-8.
JEYAPALAN, J.K. (1986) "Axial Capacity of Vibro-driven Piles," Unpublished
Internal Report, U.S. Army Corps of Engineers, Waterways Experiment Station,
Vicksburg, MS.
JONES, J.P., and NEWCOMB, F.M. (1963) An Introduction to Pile Driving.
Stanford University Construction Institute, Technical Report 23, June 1963.
JONKER, G. (1987) "Vibratory Pile Driving Hammers for Pile Installations and
Soil Improvement Projects." Proceedings of the Nineteenth Annual Offshore
Technology Conference, Dallas, TX. OTC 5422, pp. 549-560.
KRÄMER, W. (1967) "Untersuchungen über den Einsatz ver Vibrationsrammung
bei Rammelementen des städtischen Tiefbaues," Technische Mitteilungen
Krupp, Werksberichte, Vol 25, No. 1-2, April, pp. 39-50.
KENSETSU KIKAI CHOSA CO., LTD. (1975) "The Dream Island: A Report on
Vibration Pile Driving of Junction Steel Tube at the Tokyo Waste Disposal Area."
Kensetsu Kikai Chosa Co., Ltd., Osaka, Japan.
KENSETSU KIKAI CHOSA CO., LTD. "Report on Study of Piles Driven by
Vibratory Hammer." Kensetsu Kikai Chosa Co., Ltd., Osaka, Japan.
are included in this bibliography. Those who are interested in these works should consult this
bibliography directly.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 45 of 50, 1989,1992 Don C. Warrington
KONDNER, R.L., and EDWARDS (1960) "The Static and Vibratory Cutting and
Penetration of Soils." Highway Research Board Proceedings, Vol. 39, pp. 583-
604.
LARNACH, W.J., and AL-SHAWAF, N.A. (1972) "The Vibratory Driving of Piles
in Sand." Ground Engineering, Vol. 5, No. 5, pp. 22-24.
LE HOUDEC, D., and YOTTE, S. (1986) "Transmission in the Ground of Vibra-
tions Created by Vibratory Driving of a Circular Pile." (in French) Mechanique-
Materiaux-Electricité, No. 417, July-October, pp. 48-51.
LIGTERINK, A., VAN ZANDWIJK, C., and MIDDENDORP, P. (1990) "Accurate
Vertical Pile Installation by Using a Hydraulic Vibratory Hammer on the Ar-
boath Project." Proceedings of the Twenty-Second Annual Offshore Technology
Conference. Offshore Technology Conference, Dallas, TX, pp. 315-326.
LIKINS, G., RAUSCHE, F., MORRISON, M., and RAINES, R. (1992) "Evaluation
of Measurements for Vibratory Hammers." Proceedings of the Fourth Interna-
tional Conference of the Application of Stress Wave Theory to Piles, pp. 433-
436.
LUKOMSKII, S.I. (1959) Issledovanie Rezhimov Raboty Vibromolotov (Study of
the Operatinal Modes of vibration Hammers). VNIIstroidormash Works #24,
Moscow, pp. 3-39.
LUKOMSKII, S.I. (1960) Raschet Pruzhin Vibromolotov (Calculating the Springs
of Vibrating Hammers). Stroitelnoe I Dorozhnoe Mashinostroenie, #9, pp. 39-
41.
MAO, Y.S. (1957) Discussion, Session 6, Proceedings of the Fourth International
Conference on Soil Mechanics and Foundations Engineering, Vol. III, London,
pp. 192-193.
MAO, Y.S. (1958) "The Yangtze River Bridge at Hankow, China," Civil Engineer-
ing, Vol 28, No. 12, December, pp. 54-57.
MASSARSCH, K. R. (1983) "Vibration Problems in Soft Soils." Presented at the
Symposium of Recent Developments in Laboratory and Field Testing and Analy-
sis of Geotechnical Problems, Asian Institute of Technology, Bangkok, Thailand,
December 1983.
MASSARSCH, K. R. (1992) "Static and Dynamic Soil Displacements Caused by
Pile Driving." Keynote Lecture, Fourth International Conference on the Applica-
tion of Stress-Wave Theory to Piles, The Hague, The Netherlands, 21-24 Sep-
tember 1992.
MEDVEDEV, S.R. (1953) "The Use of Vibrators for Driving Steel Sheet Piling,"
Civil Engineering and Public Works Review, Vol. 48, No. 559, January, pp. 61,
62.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 46 of 50, 1989,1992 Don C. Warrington
MIDDENDORP, P., and JONKER, G. (1988) "Prediction of Vibratory Hammer
Performance by Stress Wave Analysis." Presented at the Third International
Conference on the Application of Stress-Wave Theory to Piles, Ottawa, Ontario,
25-27 May 1988.
MILITARY ENGINEER (1962) "Sonic Pile Driver -- Tests and Performance," The
Military Engineer, Vol 54, No. 362, November-December 1962, pp. 440-441.
MINING MAGAZINE (1966) "Sonics Technology in Pile Driving, " Mining Maga-
zine, Vol. 115, No. 1, July, pp. 71, 73.
MOSHER, R.L. (1987) "Comparison of Axial Capacity of Vibratory Driven Piles
to Impact Driven Piles." USACEWES Technical Report ITL-87-7.
MOSHER, R.L. (1990) "Axial Capacity of Vibratory-Driven Piles Versus Impact-
Driven Piles," Presented at the 69th Annual Meeting of the Transportation
Research Board, Washington, DC, 7-11 January 1990.
NEW ENGLAND CONSTRUCTION (1962) "Guild Drives Pile Sonically at Har-
vard, " New England Construction, October 22.
NEWFARMER, L.R. (1966) "Quiet, the Pile Driver, " Mineral Information Ser-
vice, California Division of Mines and Geology, Vol. 19, No. 4, April, pp. 55-58.
O'NEILL, M.W., and VIPULANANDAN, C. (1989) "Appropriate Field Measure-
ments for Testing Capacity - Prediction Methods for Piles Installed by Vibra-
tion." Presented at the Fourteenth Annual Members' Conference of the Deep
Foundations Institute, Baltimore, MD, 9-11 October 1989.
O'NEILL, M.W., and VIPULANANDAN, C. (1989) "Laboratory Evaluation of
Piles Installed with Vibratory Hammers." NCHRP Report 316. Washington:
Transportation Research Board, National Research Council.
O'NEILL, M.W., VIPULANDAN, C., and WONG, D.O. (1990a) "Evaluation of
Bearing Capacity for Vibro-Driven Piles from Laboratory Experiments," Pre-
sented at the 69th Annual Meeting of the Transportation Research Board,
Washington, DC, 7-11 January 1990.
O'NEILL, M.W., VIPULANDAN, C., and WONG, D.O. (1990b) "Laboratory Mo-
deling of Vibro-Driven Piles." Journal of Geotechnical Engineering, Vol. 116, No.
8, August 1990.
O'NEILL, M.W., VIPULANDAN, C., and WONG, D.O. (1990c) "Behavior of
Vibro-Driven Piles in Sand." Journal of Geotechnical Engineering, Vol. 116, No.
8, August 1990
O'NEILL, M.W., and VIPULANANDAN, C. (1991) "Modeling of Penetration
Resistance and Static Capacity of Piles Driven by Vibration at the Pioneer Freez-
er Site, Syracuse, NY, and Laboratory Model Tests." Report to the Deep Founda-
tions Institute, 1 October 1991.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 47 of 50, 1989,1992 Don C. Warrington
O'NEILL, M.W., and VIPULANANDAN, C. (1992) "Modelling of Vibratory Pile
Driving in Sand." International Journal for Numerical and Analytical Methods in
Geomechanics, Vol. 16, pp. 189-210.
PACIFIC BUILDER AND ENGINEER (1962) "Sonic Pile Driver Used for First
Time on Building Foundation," Pacific Builder and Engineer, Vol. 68, No. 9,
September, p. 13.
PARKASH, S., RANJAN, G., and GHUMMAN, M.S. (1989) "Response of a Pile
Driven by Longitudinal Vibrations." Proceedings of the Twelth International
Conference on Soil Mechanics and Foundation Engineering, pp. 959-962.
PAUNESCU, M. (1966) Folasierea Vibratiilor La Executarea Unor Lucrari de
Fundatii. Editura Tehnica, Bucuresti, 302 p.
PEREZ, H.T. (1961) "Rig Drives piles ultra fast...with ultrasonic waves."
Construction Methods and Equipment, Vol 43, No. 11, November 1961, pp. 82-
83.
PERLEI, H.T. (1964) Jcyjdfybz7 Aeylfvtyns7 b Vt[fybrf Uheynjd (Shallow, Deep
Foundations and Soil Mechanics) Consultants Bureau, New York, May-June, pp.
147-152.
RAGULSKIS, K., and YURKAUSKAS, A. (1985) Db,hfwbz Gjlibgybrjd (Vibration
of Bearings). Mashinostroyeniye, Moscow
RESEIGH, A.S. (1961) "Sonic Waves Drive Piles," Providence Sunday Journal,
October 29, 4 p.
RESEIGH, A.S. (1962) "Sonic Pile Driver Proves Worth, " Providence Sunday
Journal, July 22, 2 p.
RICKARD, A.W. (1965) "Pile Driving methods and Plant, " The Plant Engineer,
Vol. 9, No. 7, January-February, pp. 195-201.
RIPLEY, J.G. (1964) "Vibro Rig Speeds Pile Driving, " Engineering and Contract
Award, Vol. 77, No. 5, May, pp. 55-57.
RODGER, A.A., and LITTLEJOHN, G.S. (1980) "A Study of Vibratory Driving on
Granular Soils," Geotechnique, Vol 30, No. 3, pp. 269-293
ROSS ESSON, D.M. (1963) "Pile Driving by Vibration," Civil Engineering and
Public Works Review, Vol. 58, February, pp. 205-208; March, pp. 389, 391.
RUSAKOV, I.G., and KHARKEVICH, A.A. (1942) Vynyzhdennye Kolebaniya
Sistemy Udaryaioshcheisya ob Ogranichitel (Forced Vibrations of a System
Impacting on a Limiter) Zhurnal Tekhnicheskoi Fiziki 12, #11-12, Moscow, p.
261.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 48 of 50, 1989,1992 Don C. Warrington
SATTER, M.A. (1990) "Bearing Capacity Prediction from Pile Dynamics," Pre-
sented at the 69th Annual Meeting of the Transportation Research Board,
Washington, DC, 7-11 January 1990.
SATTER, M.A. (1991) "Low-Frequency Vibropile Driving and Prediction of
Dynamic Tip Resistance of Piles." Transportation Research Board, No. 1331.
SANTONI, P. (1993) "Specifications for Control of Vibrations During Blasting
and Pile Driving." Master's Thesis, Northwestern University, Evanston, IL.
SAVINOV, O.A. (1964) Raboty Po Sozdaniyu Novogo Vibratsionnogo Oborudo-
vaniya Dlya Pogruzheniya Svai (Studies on the creation of a new vibration
equipment for Driving Piles). TsINTIAM OS-U, pp. 59-65.
SCHMID, W.E., and HILL, H.T. (1966) "The Driving of Piles by Longitudinal
Vibrations." Princeton Soil Engineering, Research Series No. 4, June 1966.
SCHMID, W.E. (1968) "Driving Resistance and Bearing Capacity of Vibro-Driven
Model Piles," STP 444, American Society for Testing and Materials, pp. 362-375.
SCHMID, W.E. (1970) "Low Frequency Pile Vibrators. " Conference on Design
and Installation of Pile Foundations of Cellular Structures, Lehigh University,
Bethlehem, PA, Proceedings, pp. 257-265.
SCHMIEQ, H., and VIELSACK, P. (1986) "Influence of Friction on a Harmonical-
ly Forced Rotational Oscillator in Dry Sand." Acta Mechanica, Vol. 62, pp. 169-
182.
SCHMIEQ, H., and VIELSACK, P. (1987) "Irreversible Displacement in Dynamic
Systems as Applied to Pile Drivers." (in German) International Journal of Non-
Linear Mechanics, Vol. 22, No. 1, pp. 15-25.
SHEKHTER, O.J. (1955) "The Amplitude of Force Vibrations of Piles as a Func-
tion of Vibrator Characteristics." Science Research Institute, Proceedings, Vol 2,
pp. 3-7.
SMART, J.D. (1970) "Vibratory Pile Driving." Doctoral Thesis, University of
Illinois at Urbana-Champaign.
SMITH, I.M., and TO, P. (1988) "Numerical Studies of Vibratory Pile Driving,"
International Journal for Numerical and Analytical methods in Geomechanics,
Vol. 12, pp. 513-531.
STEFANOV, G., and BOSHINOV, B. (1977) "Bearing Capacity of Hollow Piles
Driven by Vibration." Ninth International Conference on Soil Mechanics and
Foundation Engineering, Tokyo, Japan, Proceedings, Vol. 2, pp. 753-758.
STORZ, M. (1991) "Chaotic Motion in Pile-Driving." Soil Dynamics and Earth-
quake Engineering V, First International Conference Soil Dynamic Earthquate.
Computational Mechanics Publ., Southhampton, England, pp. 503-512.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 49 of 50, 1989,1992 Don C. Warrington
SZECHY, C. (1961) "The Effects of Vibration and Driving upon the Voids on
Granular Soil Surrounding a Pile." Proceedings of the Fifth International Confer-
ence on Soil Mechanics and Foundations Engineering, Vol. 2, pp. 161-164.
TSAPLIN, S.A. (1953) Vibroudarnye Mekhanizmy Dlya Dorozhno-Mostovogo
Stroitelstva (Impact-Vibration mechanisms for Road Bridge Construction).
Avtotransizdat, Moscow.
TSCHEBOTARIOV, G.P. (1959) "How Russians drive piles by vibration."
Engineering News-Record, 16 July 1959, pp. 53-54.
TSCHEBOTARIOV, G.P., and BODINE, JR., A.G. (1962) "More on Pile-Drivers, "
Civil Engineering, Vol. 32, No. 2, February, p. 63.
TSEITLIN, M.G. (1973) "Improvement of the Capacity of Vibrating Hammers for
Driving Pipes into Soils." Soil Mechanics and Foundation Engineering (English
Translation of Osnovaniya, Fundamenty i Mekhanika Gruntov), Vol No. 3, May-
June, pp. 152-156.
TSEITLIN, M.G., and KOSHELEVA, A.A. (1984) "Vibratory Embedment of Long
Piles and Tubes and Their Extraction." Soil Mechanics and Foundation Engi-
neering (English Translation of Osnovaniya, Fundamenty i Mekhanika
Gruntov), Vol. No. 3, May-June, pp. 112-117.
TSEITLIN, M.G., VERSTOV, V.V., and AZBEL, G.G. (1987) Vibratsionnaya
Tekhnika I Tekhnologiya V Svainykh I Burovikh Rabotakh (Vibratory Methods
and the Technology of Piling and Boring Work). Stroiizdat, Leningradskoe
Otdelenie, Leningrad.
TSEITLIN, M.G., and IZOFOV, V.O. (1989) "Vibro Pile-Driving of Metallic Sheet
Piles Under Reconstruction and Urban Development Conditions." Soil Mechan-
ics and Foundation Engineering (English Translation of Osnovaniya, Fundamen-
ty i Mekhanika Gruntov), Vol. 26, No. 2, September, pp. 37-40.
WARRINGTON, D.C. (1989) "Theory and Development of Vibratory Pile Driving
Equipment." Proceedings of the Twenty-First Annual Offshore Technology
Conference, Dallas, TX. OTC 6030, pp. 541-550.
WARRINGTON, D.C. (1990) "Method for Analysis of the Drivability of Piles by
Vibration," Presented at the 69th Annual Meeting of the Transportation Re-
search Board, Washington, DC, 7-11 January 1990.
WARRINGTON, D.C. (1992) "Vibratory and Impact-Vibration Pile Driving
Equipment." Pile Buck, Second October Issue 1992. Pile Buck, Jupiter, FL.
WHITE, J.L. (1990) "Understanding the Vibratory Pile Driver/Extractor: A Field
Man's Perspective." Presented at the Fifteenth Annual Members' Meeting of The
Deep Foundations Institute, Seattle, WA, 10-12 October 1990.
VIBRATORY AND IMPACT-VIBRATION PILE DRIVING EQUIPMENT
Page 50 of 50, 1989,1992 Don C. Warrington
WONG, D.O. (1985) "Design and Analysis of an Apparatus to Simulate Density
and Stresses in Deep Deposits of Granular Soils." Master's Thesis, Department
of Civil Engineering, University of Houston, pp. 53-55.
WONG, D.O. (1988) "Driveability and Load Transfer Characteristics of Vibro-
Driven Piles." Ph.D. Thesis, University of Houston, December, Order Number
89-12678, 368p.
WU, P.K. (1966) "The Resistance of Soils in Vibro-Sinking of Precast Reinforced
Concrete Pipe Piles of Large Diameter." Proceedings of the Sixth International
Conference on Soil Mechanics and and Foundation Engineering, Montreal,
Canada.
YANG, E.L. (1967) "An Analytical and Experimental Investigation of the Effects
of Superimposed Longitudinal Vibratin on the Rate of Penetration of a Pile-
Simulating Rod," Ph.D. Thesis, Ohio State University, Order Number 67-10934,
151p.
... The beginnings and development of vibratory technology for the installation of piles is a story that has been documented elsewhere (Tseitlin, Verstov, and Azbel (1987); Warrington (1992).) The productivity improvements in its use, especially with the installation of sheet piling and large diameter casings, represent a significant advance in construction technology. ...
... Although this equation isn't very useful per se, its solution is used to define many vibratory parameters on a practical basis. These are discussed at length in Warrington (1992). Turning to our current task, Tseitlin et al. (1987) begin their presentation with the addition of soil resistance to this model, as shown in Figure 3. ...
... It would be interesting to see how this can be related to a methodology which attempts to configure (or match) a given vibrator to a given pile-soil system. The method to be studied is the one generally attributed to Savinov and Luskin (1960), but it appears in a number of other publications, such as Erofeev, Smorodinov, Fedorov, Vyazovkii, and Villumsen (1985); Tseitlin et al. (1987); Warrington (1992). This is not intended as yet another outline of the method, but an inter- The basic objectives of this method are to insure that: 1. ...
... However, the noise generated by impact driving can be a severe environmental issue in urbanised areas. Moreover, experience suggests that, in granular soil deposits, vibratory driving is the more efficient installation method (GDG, 2015;Holeyman, 2002;Rodger and Littlejohn, 1980;Viking, 2002;Warrington, 1992). However, in some cases, excessive ground vibrations have been reported as a result of vibratory driving (Athanasopoulos and Pelekis, 2000;Deckner, 2013;Meijers and van Tol, 2005;Wiss, 1980). ...
... Vibrator types Electric vibrators were first developed in the mid 1950s in the Soviet Union and were subsequently introduced in Japan and Europe (Warrington, 1992). Hydraulic vibrators were developed in Europe in the mid 1960s and are now widely used in Europe and North America. ...
... Vibrators for pile driving typically operate in a frequency range of 10-40 Hz. Detailed descriptions of different types of vibrators and their operation have been presented by, for example, Warrington (1992), Massarsch (2000) and Viking (2002). ...
Article
Full-text available
The installation of piles by vibratory methods is discussed and illustrated by case histories. The influence of vibration frequency – which can be controlled during vibratory driving but not during impact driving – on pile penetration, bearing capacity and emission of vibration is examined. The driving process affects the performance of vibratory-driven piles more strongly than impact-driven piles. Concepts are presented for assessing driveability. The importance of resonance of the vibrator–pile–soil system (system resonance) for driveability and pile bearing capacity is explained. Ground vibrations measured on and below the ground surface show that strong oscillating horizontal stresses are generated. These stresses can temporarily reduce the shaft resistance during driving, which can explain why vibratory driving is effective even in dense granular soils. Model tests show that, in granular soils, the bearing capacity of piles vibrated after driving at system resonance is significantly higher than that of piles installed only at high frequency. A concept is described suggesting that, during vibratory driving at high frequency, a zone is created adjacent to the pile shaft where the normal effective stress acting against the pile shaft is reduced due to arching. This arching effect can explain the reduced shaft resistance of piles installed at high frequency.
... The sheet pile is used as earth retention to prevent sliding slopes with interlocking edges, while prestressed spun concrete pile is suitable to be used in various types of soil condition due to its high effectiveness in bending moment capacity, axial compressive stress and axial tensile stress. This type of pile is installed by hydraulic jacking equipment and it is environmental friendly, free from noise, vibration and air pollution [1]. ...
... The excitation maybe force applied to the mass of a single degree of freedom system in motion of the foundation that supports the system. The force for the system can be determined using Eq (1): (1) where: ω = frequency of the force determined by the force Xo = static equilibrium configuration or initial position t = time ...
Conference Paper
Full-text available
Basically, many major structures across the world such as towers, high rise building, houses and bridges utilize pile as a support material. The use of pile is important to strengthen the structures. However, this has led to another problem to the nearest surrounding structures resulted from pile driving. As part of a construction work, unavoidable pile driving activity generates a vibration towards the surrounding structures if uncontrolled may cause damage to the adjacent structure. As the current construction works are frequently located in urban areas where the distance between the nearest building structures is not far, vibration may cause damage to nearby structures. Knowing which part of the building that is mostly affected by various vibration patterns from the impact of pile driving is crucial. Thus, it is very important to predict the impact of vibration during piling installation work. This paper reviews the vibrations generated by piling activity toward surrounding structures in terms sources of vibration, impact of piling installation, pile-soil interaction, and factors affecting the vibration impact of building as well as to study the parameters involved in vibration generation during piling works.
... end of the Soviet era, left many "loose ends" in our understanding of the technology. (For a description of the physical setup of vibratory pile driving equipment, see Warrington (1992).) One of those "loose ends" is the assumption that rotational speed is constant. ...
Technical Report
Full-text available
Virtually all treatments of power consumption and modelled performance for vibratory pile driving equipment assume a constant rotational speed of the eccentrics. In reality this is not possible due to the inertial effects of the eccentrics themselves and the necessity that, without inertia, the power output of the motor for the eccentrics must follow the instantaneous power requirements, which continuously vary. In this paper the rotational inertial effects of the eccentrics are included in the calculations. Because of the non-linear nature of the equations, a numerical model was developed to estimate the dimensionless torque required to turn the eccentrics at a target rotational speed. The results track closely with those of the continuous torque model described by Warrington (2006) for a wide variety of inertia/eccentric moment ratios, although there are exceptional cases if the peak acceleration is increased and the frequency decreased. As an excursus, the method of computing the inertia/eccentric moment ratio and its corresponding pendulum frequency is described in detail for those who can apply this to other problems.
... Vibratory impact piles (piling device) at a specific depth depends on what was previously mentioned of important considerations to determine the depth of concrete piles. There are many different types of pile driving methods, including hydraulic hammer, pneumatic hammer, vibrator, hydraulic pressure and others (Warrington, 1989). ...
Article
Full-text available
In this research, we will talk about Prefabricated and Prestressed Concrete piles in general and their types, what they are manufactured and developed over the years and how much they cost according to international standards and their usefulness in overcoming soil problems and pre-construction problems, then we will talk specifically about Prefabricated and Prestressed Bio-Concrete piles and the difference between them and ordinary piles. The research will also present the opinions of people who have delved into and discussed this topic and the opinions of all engineers, economists and specialists in general. In the end, this research will conclude with a complete and simplified summary of Prefabricated and Prestressed Bio-Concrete piles and all the information related to them in foundation engineering and other points that the engineer or specialist has not encountered before.
... Modern construction vibrators are among the most sophisticated machines in foundation engineering (Warrington 1992;Gavin and Doherty Geosolutions 2015). Major improvements in the design, operation, and control of vibrators have been achieved during the past decades (Warrington 1989;Massarsch and Westerberg 1995;Viking 2002;Holeyman 2002;). ...
Article
Full-text available
Vibratory sheet pile driving is a widely used foundation method. In order to investigate the effect of different operational parameters, such as vibration frequency and eccentric moment on sheet pile to ground interaction, carefully monitored and documented field tests were performed. A single sheet pile was vibrated into a sandy soil deposit (esker) and different operational parameters were varied. The interaction between the vertically oscillating sheet pile and the surrounding ground was studied, using sensors on the vibrator and on the ground in the vicinity of the sheet pile. The effect of vibration frequency and eccentric moment on sheet pile penetration speed and emitted ground vibrations is presented. When the sheet pile is vibrated at the resonance frequency of the vibrator–sheet pile–soil system (system resonance), ground vibrations increase significantly and sheet pile penetration speed decreases. It is concluded that the vibration frequency is an important parameter for the efficient and environmentally safe installation of sheet piles. These tests provide insight into the interaction of a vibrated sheet pile and the surrounding ground. Based on these results, guidelines for the efficient and environmentally friendly installation of piles and sheet piles are proposed. DOI: 10.1061/(ASCE)GT.1943-5606.0002520. © 2021 American Society of Civil Engineers.
... For certain types of piles and soil conditions, vibratory drivers are the preferred equipment type for pile installation. The construction and application of these machines, along with some of the history of the technology, is discussed in depth by Warrington (1992). Additional details on the history are given by Viking (1997). ...
Technical Report
Full-text available
This paper details the mathematical modelling of vibratory pile driving systems using a linear model with the objective of obtaining a closed form solution to estimate either the power requirement of the machine, the torque requirement of the motor driving the eccentrics, or both. It begins by reviewing the system model for the system without a suspension, which is used to enable connection of the vibrating machine with a crane, a mast of a dedicated machine, or an excavator. It proceeds to solve the equations of motion for a system with a suspension, using Laplace transforms and solving the inverse transform using residues and complex integration. The model indicates that, under certain conditions, both the amplitude and the power consumption of the system increase with a suspension, but the results make the practical implications of the result uncertain. Finally a simple set of equations is developed for actual vibratory design which result in the suspension being ignored and the necessary torque of the driving motor computed.
... Tsaplin [14,54] and Barkan [5] had investigate impact forces. Of particular concern was size of machine. ...
Article
Impact moling is an effective method of pile driving and percussive drilling to bore underground tunnel for various civil applications such as pipe, cable and ducts installation. An effective electro-vibroimpact system has been built on the basis of interactions between two sources of electromagnetic force. A vertical downward progression of mechanism into hard or brittle material required an increased magnitude of impact force within a compact geometry. Horizontal progression into clay is tested by combining periodic impact and static forces that produces an effective progression rate. As a consequence of this experimental work, a prototype electro-vibroimpact system is tested. Electrical circuitry consists of a timer and batteries which is a compact arrangement, functioning as waveform generator, and power supply. A cylindrical hollow aluminium tube houses the main components such as electromagnetic solenoids and oscillating bar within. This protects the main components from clay while progressing into soil and also reduces soil resistance with a minimal surface area. A mathematical model has also been numerically solved for both single and two degreeof-freedom system. Correlation has been achieved to a certain extent, and it is possible either deploy or further optimise this system.
Article
Within the framework of this work, one sought to better understand the elementary mechanisms which control the process of vibratory driving and to highlight the parameters which have significant influences on this process, by the use of physical modelling in a calibration chamber. The influence of each parameter is represented by the vibro-drivibility (penetrability of the pile by the vibratory driving), the evolution of tip resistance and that of lateral friction. We developed an instrumented probe that allows to measure separately tip resistance and lateral friction, in order to study the mechanisms of mobilization of these two parameters during the process. We focused, within the framework of this work, on parameters related to the head loading such as the frequency of vibration, the average load and the cyclic amplitude; and on parameters related to the sand mass, namely sand of Fontainebleau, such as the level of constraint of consolidation and the state of saturation of sand. To study the influence of each parameter, a series of tests was carried out by varying one parameter from one test to another while fixing the other test parameters. We could highlight the significant influence of the cyclic amplitude ratio on the average load (Fcyc/F0) on the displacement of the probe. The probe penetrates more quickly with a higher ratio than with a small ratio. The results obtained also show that the higher the frequency is, and the more the probe is inserted and the less tip resistance and lateral friction are mobilized.
Article
The purpose of this study is to shed light on the phenomena occurring during the propagation of the vibrations caused by a pile being driven into sandy soil with the aid of a vibratory pile driver. During the course of this study the authors were able to estimate the decrease in the shock wave amplitude as a function of the distance to the source and to compare the contributions of each type of wave or of each displacement component. An analysis on a laboratory tank-type model made it possible to approximate experimentally certain surface measurements of vertical displacement.
Article
Methods available for estimating the bearing capacity of piles installed with vibratory drivers are inadequate and do not explicitly incorporate important variables, such as soil parameters and in situ stresses. The influence of relative density (65% and 90%), particle size (0.2 mm and 1.2 mm), and in situ horizontal stress (10 psi and 20 psi) on the load-movement relationship and bearing capacity of vibro-driven displacement piles in sand is investigated using a large-scale laboratory testing system. The test results indicate that, among the variables investigated, the most important parameter influencing the rate of penetration and the bearing capacity of the vibro-driven piles is the initial relative density of sand deposit. Based on pile capacity tests and analytical study, several models are proposed to predict the nonlinear unit load-transfer curves, load-movement relationships and bearing capacity of vibro-driven displacement piles. The model parameters are related to the important test variables investigated in this study. The model predictions are in agreement with the experimental results. Performance of vibro-driven piles is compared with that of impact-driven piles.
The study of skin friction developed in the present article falls within the scope of research work on high-frequency vibro-piling (1,500 to 3,000 Hz). Our laboratory measurements performed thus far have concerned the general behavior of the test unit without dissociating point force and skin friction. Previous studies have indicated that vibro-piling is only possible when an excitation frequency is used equal to one of the frequencies characteristic of the system. A more refined analysis of the phenomena involved depends on determination of the skin friction coefficient which was measured in our laboratory using a horizontal test bench. It was thus shown that this friction coefficient is a decreasing function of the power transmitted by the exciter to the sheet pile: it is directly related to the depth of penetration of the sheet pile into the sand; and it is independent of the forward movement velocity of the sheet pile without excitation but increases with this velocity in the presence of excitation, thereby enabling reconstruction of a vibro-driving curve to provide satisfactory estimation of refusal.
Article
Two types of vibratory pile driving have been identified by the authors termed respectively 'slow' and 'fast' vibrodriving. The occurrence of slow or fast motion is determined by the initial soil density, pile diameter, displacement amplitude and acceleration of vibration. A theory and interactive computer simulation of the case of slow vibratory driving has been developed. The motion is considered to be that of a rigid body subject to viscous-Coulomb side and elasto-plastic end resistance under a combined sinusoidal excitation and static surcharge force.
Article
Summary The periodic motion of a body in dry sand is influenced by an unknown resistance in the contact surface. A rotational oscillator is used as measurement device to detect some basic principles. Hypotheses about the pseudo-constitutive laws for the interaction between sand and oscillator allow the calculation of a steady state motion. Experimental investigations confirm the theoretical assumptions and show the dominant influence of friction on the motion.
Article
TO better understand the factors influencing the driveability and bearing capacity of vibro‐driven piles, a large‐scale laboratory study was performed. The testing system consisted of a pressure chamber to simulate in situ stresses, a 4‐in.‐ (102‐mm‐) diameter instrumented displacement pile, a model vibratory driver, and a model impact hammer. The influence of soil and vibro‐driver parameters, in situ stress conditions, and restriking with an impact hammer on the performance of vibro‐driven pile was investigated. The soil parameters of interest were particle size (effective grain size of 0.2 mm and 1.2 mm) and relative density (65% and 90%). The vibratory‐driver parameters of interest were the frequency, eccentric moment, and bias weight applied to the vibrator. Based on maximum rate of penetration of the pile, an optimum driver frequency of 20 Hz was observed for the vibro‐driver‐pile‐soil system under investigation. The optimum driver frequency was not affected by the range of soil conditions, eccentric moment, and bias weight investigated. The relative density of soil has the greatest influence on the rate of penetration of vibro‐driven piles. Static and dynamic unit‐load‐transfer relationships were developed for piles driven by vibration and compared with those obtained for piles driven by impact under similar conditions. Impact‐driven piles developed higher capacity than vibro‐driven piles in medium‐dense sand (65% relative density), but the reverse was observed at 90% relative density, with vibro‐driven piles having greater bearing capacity.
Article
The results of the investigations described in this article indicated that the driving capacity of vibratinghammers in soils of medium density can be improved without increasing the impact velocity, by increasing the length of the path traveled jointly by the hammer and the pipe after each blow. When the vibrating hammer operates under longitudinal action, the above-mentioned effect can be obtained by adjusting the force in the springs, in case of large negative gaps. High driving capacity is possessed also by vibrating hammers operating under longitudinal-rot ary action, in which the path traveled jointly by the hammer and the pipe is increased as a result of torsional vibrations of the driven pipe. The experimental investigations conducted in order to justify the analytical m odel indicated that during vibration-impact driving of pipes open at the bottom, the blow can be regarded as inelastic and instantaneous, while the penetration resistance can be regarded as plastic. A longitudinal-act ion free spring vibrating hammer and a longitudinal-rot ary action vibrating hammer were investigated.
Article
The feasibility of the vibratory method of driving piles was investigated. It is known that vibratory pile driving devices have been used successfully in the Soviet Union and that this technique is claimed, by many authorities, to be more efficient than the more conventional means of pile driving. The investigation included liaison with United States firms engaged in developmental work in vibratory pile driving, a literature search for authoritative information in this field and the preparation of a bibliography. Since vibratory pile driving devices may have advantages over conventional equipment, it is recommended that the Laboratory continue its investigation of the vibratory pile driving concept. (Author)