PILE DRIVING EQUIPMENTS

PREPARED BY:C.UMA

U06CE056

What is pile driving Types of hammers Types of driving accessories

Contents

Definition:The operation of forcing a pile into the ground is known as “pile driving”.

Pile driving is done on “driven piles” and “driven and cast in-situ piles”.

What is Pile Driving

Fig. Schematic diagram of Pile Driver with Crawler Mounted Rig

Drop hammer Single-acting hammer (steam or pneumatic) Double-acting hammer (steam or

pneumatic) Diesel hammer (internal combustion) Vibratory hammer

Types of Pile Hammers

Drop Hammer

Fig. Schematic diagram of a drop hammer Fig. Drop hammer

The hammer or ram is raised by pulley and which is allowed to fall on top of the pile.

This is the simplest type. The drop hammer is simple but very slow

and is used for small jobs only.

Features of Drop Hammer

In this type, hammer is raised by steam or compressed air and is allowed to drop on the pile head.

Weight of hammer 1000 to 10000 kg Height of fall 60 to 90 cm Advantage: the blows may be delivered

much more rapidly than in case of drop hammer.

Single-Acting Hammer

Fig. Single acting hammer showing various strokes during driving action

Double-Acting Hammer

Fig. Double-acting hammer Fig. Schematic diagram of a typical drop hammer

Steam or air pressure is employed to lift the ram and then accelerate it downward.

The blows are more rapid; 90 to 240 blows per minute.

Less time required to drive the pile Easy pile driving Weight of ram may be 1000 to 2500 kg.

Features of Double-acting hammer

Steam operated hammers are more efficient with circulating steam generators.

If the hammer is to be operated under wayer, compressed air type operation is necessary.

Advantage: pile in continuous motion, reduced effect of impact, thus minimal damage to pile head

Suitability of Double-Acting Hammer

Works on internal combustion of diesel oil. Energy provided both for raising the

hammer and for downward stroke. These can be single or double acting type This type is self contained, economical and

simple. A hydraulic pressure activated hammer is

faster and lighter compared to equivalent steam hammers.

Diesel Hammer

Fig. Diesel hammers

The driving unit operates at high frequency and thus, the driving is quick and quiet.

A variable speed oscillator is used for the purpose of creating resonance condittions.

Easy penetration of the pile with a relatively small driving effort.

Vibratory Hammer

Fig. Vibratory hammer

Types of Vibratory Hammers Low frequency hammers Medium frequency hammers High frequency hammers Sonic or resonant hammers Impact vibration hammer

It is not possible for striking the end of the ram of an impact hammer to directly adapt itself to all shapes of piles; therefore, it is necessary to have driving accessories of various types to be inserted between the bottom of the hammer and the pile.

Driving accessories

Hammer cushion Anvil Helmets Mandrels Pile cushions Pile caps

Various Driving Accessories

Fig. Hammer cushions

Fig. Pile driving accessories

“GEOTECHNICAL ENGINEERING”, by C.Venkatramaiah, “Wiley Easter Ltd”

Unified Facilities Criteria (UFC), Pile driving equipment

Refernces

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