01 July 1997
5 percent or so normal for vibratory hammers), this variation generally does not impede the continuous,
stable operation of the equipment. These hammers have very limited usage, at the present time, and are not
manufactured in the United States.
f. Types of Pile Driven with Vibratory Hammers. Vibratory hammers are used to drive a large variety of
piles. A quantitative method of evaluating these was presented in chapter 2.
g. Qualitative descriptions are listed below.
(1) Sheet Piling. To drive steel sheet piling, the sheeting is set up according to normal American
practice, namely to set the wall in place using a template 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 14 inches 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.
An alternate method of driving sheeting with a vibratory hammer is to set the sheet piling as they are driven.
As a rule, in this case the sheets are driven one at a time. 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 upward and
downward. Impact-vibration hammers for sheet piles generally are equipped with clamps instead of an
(2) H-Beams. The conditions to drive H-beams are similar to driving sheeting; however, when the
pile' 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.
(3) Caissons and Pipe Pile. Caissons are a versatile item, extensively used with drilled shafts. To
drive these, a special 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
open-end pipes, although some closed-end 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 where two sets of clamps are used, the beams are being configured in an " "
(4) Concrete Piles. Concrete pile installation with vibratory hammers is rare in the United States but
more common abroad. It is done with both prismatic (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. An alternative to this is to use an impact-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.
(5) Wood Piles. As it is almost exclusively bearing pile, wood is rarely vibrated in the United States.
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.
3-3. RIGS. All pile drivers require some kind of rig to lift hammer and pile and to guide the system into the
ground. Although there are many different configurations used for this purpose, for impact hammers the most
common is shown in figure 3-22. This is a commercial crane adapted for pile driving. There are many
variations of this, depending upon the application. However, the ultimate choice of a rig configuration is very
dependent upon its availability. Most of these rigs can be adapted to a floating, barge-type configuration as