HYDRAULIC PILE HAMMER GLOSSARY
The BRUCE Hydraulic Hammer Standard Glossary of Terminology has specially been prepared with the object of unifying the various technical terms and expressions targeted for majority members of construction conductors on sites who are being involved with the BRUCE Pile Driving Equipment to be operated at the various different piling work taking place In the world.
We wish that this standard would be helpful for the customers.
It is consisting of three main parts of a shell, a Bladder and a oil port that is functioning the control of energy in respect of storage, maintain, compensation and reduction & absorption the pulsation and impact in the hydraulic system.
It is placed on a Logic Block of Cylinder Assembly of BRUCE Hammer to perform the duties in terms of absorbing shocks from possible hydraulic damage and reducing the flow fluctuations for the hoses
The part of a power operated hammer which receives the blow of the ram and transmits it to the pile.
A pile which is driven in an angle to the vertical, normally adopted to counteract horizontal force acting on vertical piles.
It is literally the capacity of soil to support the loads to the ground, but, calculating this became more complicated because so many other factors are influenced to gain this formula on the basis of energy mass conservation law and times a safe ratio 3 is Ultimate Bearing Capacity
A pile driven or formed in the ground for transmitting the weight of a structure to the soil by the resistance developed at its point and by friction along its surface.
It may be driven vertically or at an inclination (raking pile) and may be required to take uplift.
It is also can be called as Blow Count by other companies In the same industry.
It is the number of Ram on the Hammer impacts or blows required to drive the pile within a given time of measurement.
Blow Rate for BRUCE Hammer is counting during the duration of one minute
A pile formed with or without a casing, by excavating or boring a hole in the ground and subsequently filling it with plain or reinforced cement concrete
The rebound of the hammer on hitting the pile.
Too much bounce is a sign of inefficient-driving as a large part of the energy is diverted from driving.
Bouncing will nearly always occur as pile is near its desired set but bouncing in the beginning is an indication that hammer is too light for the task
It is fabricated by BRUCE to wrap up the Drive Cap and to connect with a Pile Cap or a Long Pile Skirt either for onshore and offshore pile driving purposes which are a kind of auxiliary Pile Cap provided upon customers request.
There are a two Buffer Rings inserted on top of Cap Housing to absorb the shocks from rebound occurrence or other reasons.
A driven (cast in situ) pile in which a light metal casing is driven into the ground with the help of a mandrel, and after the casing has reached the required depth,
the mandrel is withdrawn leaving the casing in position to be filled with concrete.
It is called as Steel Tube Pile or Tubular Pile by many workers on sites.
This pile is manufactured in seamless spirally welded or well lap-welded and is normally installed by top driving but in difficult ground conditions and also it can be installed by a combination of drill and drive.
Casing Piles driven by BRUCE Hammer for marine and offshore application Have usually large diameter and are therefore often driven as open-ended to resist lateral and uplift loading.
However the base resistance of open-ended piles can be low in loose to medium dense granular soils.
When the BRUCE Hammer approaches the Casing Pile Driving, the working stress design method is calculated as 2,400 kg within the range of below 20 tons Hammer to select an optimum pile driving condition
BRUCE defined this as a Practical Refusal of BRUCE Hammers in accordance with Warranty Policy on the Operating Manual that described as the Hammer doesnt want to operate longer than 10 hours per day and get recess time for 30 minutes for system cooling when it continuously supposed to be operated for 2 hours of non-stop operation.
It has been developed through long years of pile driving experience and its kinds are various such as RC, PC and PHC Concrete Piles.
It normally can be divided into pre-case and cast in place concrete piles following the forming process.
It is formed and reinforced in a high quality controlled concrete piles shaping square, triangle, circle or octagonal type.
When the BRUCE Hammer approaches the Concrete Pile Driving, the working stress design method is calculated as 280, 340,and 540 kg for RC, PC and PHC Concrete Piles, respectively within the range of below 20 tons Hammer to select an optimum pile driving condition.
This type of Hammer operation has no Leader is used and normally is accomplished its pile driving work on offshore project.
The Hammer requires a lifting wire rope to lift it directly by a Crane due to the limitation of taking Cranes position when it is being apart from the land.
The Long Pile Skirt is generally used for marine and offshore pile driving job.
Cushions are used to protect both the hammer and the pile.
Cushions that protect the hammer are called hammer cushions or hammer cushions.
Cushions used to protect the pile are called pile cushions.
It is a recent days method to assess a piles Bearing Capacity by applying a dynamic load to the pile head while recording Acceleration and strain on the pile head that is also a high strain dynamic test which is applied during the pile operation.
When a Ram drops and strikes the top of the pile, a compressive stress wave travels down its shaft at a speed which is a function of the elastic modulus and mass density.
The impact induces a force and particle velocity at pile and is computed by multiplying the measured signals from a pair of strain transducers and modules and
accelerometers transmit data to a high strain dynamic testing system such as the Pile Driving Analyzer (PDA) for signal processing and the results.
A cushion consisting of a block of hardwood, plastic or other suitable material placed on top of the helmet to receive the blows of the hammer and to distribute it evenly over the surface of the helmet.
It is also called as Driven Cap??by others and it is essential to protect the heads of various piles.
The Drive Cap fabricated typically by Cast Iron material is shaped to suit the pile sections are used for this purpose.
It is wrapped by a Cap Housing following the design of Hammer structure and is provided with couples of Cushions such as a Dolley,
a Cushion Block and Cushions to protect the Hammer from operational failure may have occurred.
A pile driven into the ground by the blow of a hammer.
When steel sheet piling on other steel sections are driven with a hammer, it is essential to protect the heads of the piles;
cast steel driving caps shaped to suit the pile sections are used for this purpose.
The caps are provided with a dolly of hardwood or plastic material.
The distance the drop hammer is allowed to fall on to the helmet of the pile.
The stroke or drop is the factor that determines the impact on energy delivered by the hammer.
A hammer is raised by a winch and allowed to fall under gravity
Pile which transmits the load primarily by resistance developed at its toe.
Pile which transmits the load primarily by resistance developed at its toe.
This type is one of the most frequently used Leader type for Hammer mounting on it with a sliding connection to the Crane to move Hammer up and down in conjunction with the Guide Crawler of a Hammer.
The Guide Crawler of Hammer shaped as rounded or squared will follow the Leader to move upward and downward direction.
The connection at the top of Hammer is a Lifting Sheave to lift the Hammer by Crane and when if needed, there is normally a Pile Guide which has a method for adjusting the in or out from the Crane and it allows any type of piles to be used.
Bruce provides also Followers which is :
An extension, usually steel, used between the top of the pile and the hammer to extend the driving range of the pile (usually below water).
Pile which transmits the load primarily by friction developed along with its surface. Friction pile in loose sand is sometimes called compaction pile.
A member interposed between the head of the pile and the hammer when it becomes necessary to drive the head of the pile below the reach of the hammer.
This system is not only one of the most recently developed by Department of Transportation of USA and also most representative and widely used
in the pile driving industry that calculate after all the Bearing Capacity through the method of Dynamic Measurement and Analysis.
WEAP is short terms as Wave Equation Analysis of Pile Driving and is aiming at finding the relationship between Bearing Capacity,
Pile Stress and Blow Count known as the Bearing graph that can predict Bearing Capacity and a required ultimate Bearing Capacity.
The ultimate purpose of analyzing this GRLWEAP system is to select the most adequate Equipment with its Pile and to decide the Pile Driving Criterion with blow count for capacity and stroke.
Hammer cushions are constructed of man-made materials that are heat resistant, durable and absorb a certain amount of shock.
Common types of materials are aluminum, micarta and polymer which are in the form of disks.
Hammer cushions are located between the point of the ram or anvil and the pile cap.
Bruce adapted high quality and durable of MC-904 cushion material or Klinger Pad
Hanging leader consists of a pair of channels similar to the leader of a pile frame suspended from the jib of crane and positioned with the aid of adjustable strut.
Hanging leaders are used in conjunction with cranes.
A temporary steel cap, shaped to suit the pile, placed on the top of a pile being driven with a drop hammer or single acting hammer, to distribute the blow over the cross section and to prevent the head being damaged during pile driving.
This computerized Impact Energy Monitoring System provided by BRUCE is called IEA as a short terminology that starts with entering the basic information over ongoing project schedule to display a critical Hammer energy data through a two different operation mode which are Individual Blows and Variable-Sized Groups of Blows on the screen.
IEA from BRUCE is a highly intelligence Impact Energy Monitoring system that can evaluate all the detailed Impact Energy Data not only at job site and also at the office at a real time base transmitted through signals from Hammer.
IEA being compatible with BRUCE Hammer is widely used as Impact Energy Monitor System that is essential to calculate its Impact Energy efficiency.
(WV2/2g) expressed in kgf.m
W = weight of moving hammer in kg
V = velocity in m/s,
g = acceleration of gravity in m/s2
Energy is expressed in kgf.m. However, from the above expression, the losses due to the following shall have to be subtracted :
b) Loss due to impact
c) Loss due to temporary compression of pile, head and pile cap
d) Loss due to temporary compression of pile
e) Loss due to temporary compression of soil
It is also called as Lead by BRUCE in a short terms.
The Leader consisting of a pair of steel frame is fabricated with steel structure to mount the Hammer on it and it used in conjunction with Cranes, Pile Drivers or mechanical Excavators.
The Leaders to mount BRUCE Hammer can be utilized as a Fixed Type and U-Type that are the leading Leader type allowing it access to a difficult area and relatively easy to set up for whole operation.
Swinging Leads – These leads are attached to the crane at the top by the main cable.
They have a gate at the bottom which holds the leads around the pile and will sometimes have spikes on the bottom which are stuck into the ground or template to assist in aligning the hammer.
This type of lead is best suited for piles with little or no batter.
The advantages of this type of lead include allowing the crane to be used for other activities, they can be swung into areas with difficult access, and they are relatively easy to set up. A template must be used in conjunction with swinging leads.
Semi-fixed Leads – This type of lead has a pivot or sliding connection to the crane at either the top or bottom of the leads. Normally the connection is at the top of the leads.
Semi-fixed leads can accommodate a greater batter than swinging leads, however, they limit what the crane can do and are more difficult to set up. This type of lead also requires the use of a template.
Fixed Leader – This type of leader has connections at both the top or mid-point and the bottom of the leads.
The connection at the top is normally a pivot or rotational type connection, at the bottom there is normally a brace which extends from the crane to the leads.
This connection normally has a method for adjusting the in or out from the crane and left or right.
This allows any type of batter to be used.
This system severely limits what the crane can do and in general requires the most set-up time.
No template is required for fixed leads.
Bruce provides most kind of Leads or Leader suitable to the piling industries upon request
It is a self contained mechanism, having within itself the means of raising the pile hammer between blows.
It rests on the head of the pile and is independent of any winch except for raising it into position.
BRUCE defined it as between an average 10~12 blows per inch (10~12 blows per 25mm)
with the Hammer operating at any stroke and when the Hammer penetrates less than 2mm on an average per every 10 blows at any stroke where that occurred
the BRUCE Hammer should be stopped its pile driving work instantly according to warranty policy.
It is frequently called as Helmet by others in the same industry.
It is also called as a different name as Pile Sleeve or others say Pile Skirt by the length of piles depending on situation on shore or offshore work.
The Pile Cap from BRUCE is defined as a steel cap with relatively short in length and placed on the lowest part
of Hammer body is shaped to cap the pile to any different shapes that typically carries out on-shore foundation work.
This is the section of the pile driving system which rests between the hammer and the pile.
For concrete piles, it contains the striker plate or drive cap, a hammer cushion, and the pile cushion.
For steel piles, it will contain the striker plate or drive cap and hammer cushion only; no pile cushion is used on steel piles.
Bruce provides adequate size and high quality Pile Cap to suit most of size required and suitable as well as cushions.
Pile cushions are placed between the pile top and the pile cap on concrete piles.
Pile cushions are not used on steel piles or timber piles.
Pile cushions consist of plywood. Pile cushions are generally replaced for each pile or as directed by the Engineer.
Pile cushions are located between the top of the pile and the bottom of the pile cap
It is also called Pile Rig by others. It is the complete pile driving equipment comprising of piling frame, Leader, Hammer and winch with power unit.
Complete pile driving rig may be mounted on rafts or pontoon or rails.
Piling rig may also be a mobile unit mounted on trailers or trucks, or a special full revolving rig for another planned pile driving work
The raising and falling part of the Hammer that delivers the impacting energy to piles through Cushions inserted in
a Drive Cap in a sequential procedure whenever it carries out a repeated movement of impacting.
The Ram is logically comprised of one or more Ram Segments connected with a Connecting Rods of Cylinder Assembly of BRUCE Hammer
The bouncing of the Hammer on hitting the pile, too much of Rebound from Hammer hitting is a sign of inefficient pile driving as a large part of the energy is diverted from driving.
Rebound will nearly always occur as pile is near its desired set but Rebound in the initial stage is an indication that the hammer is too light for the task.
The Ram stay time for controlling the Rebound is being set on a Remote Control Box that controls the Hammer.
“SPT” is an abbreviation for the Standard Penetration Test, which is the most widely used in-situ soil characterization test world widely.
The SPT test involves driving a standard cylindrical sampler into the bottom of a borehole.
The total blows required from a hammer, over the interval 150 to 450 mm (6 to 18 inches) are summed to give the blow count N, in blows per foot.
The N-value is used as a basis for foundation design and as the primary index of liquefaction resistance.
Sheet Piles are made from all basic pile material either plane or combined in a form or shape so that they interlock to form a wall or sheet of piling.
The types are various and it is used when a wall or sheet of piling is required such as in case of retaining walls, coffer dams and water front structure.
Sheet Pile driven by BRUCE Hammer needs a special Pile Leg.
This is the terminology used to describe the height of the Ram that is controlled by a BRUCE Remote Control Box to start to ascend stepwise for driving a pile.
The stroke from BRUCE Remote Control Box is dependent upon Oil Flow and resistance attached Height Volume Button on a Remote Control Box so that stroke can be set for a Ram Height at any circumstance.
This is used to maintain the pile in the proper position and alignment during pile driving with especially U-Type Leader from BRUCE Hammer.
It should be constructed of steel and rigid enough to hold the pile In place and be placed within 1.5 meters of pile cut-off elevation from ground
This type is also one of the most frequently used Leader type for BRUCE Hammer mounting on the Leader for the purpose of driving into a more difficult to set up.
This type of Leader is more accurately advanced method for pile driving and more sophisticated Leader type than a Fixed Leader Type in terms of the Hammer is interlocking inside the Leader to slide or to stick to it accommodating a more precise pile driving and a greater battered piling work by the Crane lifts a whole structure of Leader.
A hoisting mechanism for lifting the Hammer or the Piles and it is consisting of a drum on which a steel rope is wound.
It is operated by power through BRUCE Power Pack or Base Machine like Cranes or Excavators owned by the customer at any of foundation construction workplace.
The Winches provided by BRUCE are used for lifting of Hammer and Piles.
It is consisting of a jet pump, supply lines and one or more jet pipes which use water to displace soil and advance a pile into the ground.