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Micro Piles |
Pressure Grouting |
Rock Anchors |
Permeation Grouting
Soil Nailing |
Compaction Grouting |
Micropiles |
Injection Grouting |
Chemical Grouting
Our
techniques apply when adding new structures:
especially
rock anchor,
microfine cement,
soil nailing,
micropile
installations for
foundation support.
We
specialize in
slope stabilization,
anchors,
permeation grouting,
foundation repair
and support,
grouting,
soil nails,
rock drilling,
micropile installations, and
sinkholes. We
use a
problem-solving approach geotechnical
architecture of buildings, bridges,
water plants, sewage plants, tunnels,
sinkholes,
caisson,
shoring,
underpinning,
agriculture, and
roads
construction. We
are experienced in these applications:
micro piles,
sinkhole repair,
permeation grouting, pressure
grout,
soil nails,
chemical grouting,
micropiles,
compaction grout, and
rock anchors.
Our specialties are
rock anchor,
acrylamide and
compaction grouting,
mini piles,
sinkhole repair,
micropiles,
acrylamide grouting, and
soil nailing.
We will continue to dedicate ourselves to
excellence,
including
insurance mortgage, in our performance, in our
integrity, and in our relationships with our
customers. We will carefully weigh our
decisions, actions, and results to make sure
that we remain the most trusted name in the
geotechnical contracting industry. Please
visit our website
http://www.rembco.com/.
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JULY
1997
Driven Piles
7-36
CALTRANS FOUNDATION MANUAL
monitoring driven pile installation are ram weight, stroke, blows per minute, energy rates
and required steam or air pressure.
Accurate determination of a given hammer's available energy is difficult. Manufacturers
calculate hammer energy differently. McKiernan-Terry uses ram weight times stroke. At one
time, Delmag calculated a hammer's energy as a function of the amount of fuel injected.
They now use the weight of the hammer times the stroke. Link-Belt considers stroke, fuel,
and the effect of the bounce chamber. Keep in mind that a hammer's rated maximum
energy is typically rated when the pile hammer is operating at or near refusal.
The Standard Specifications state that "E" is the manufacturer's rating in foot-pounds of
energy developed by the hammer. It is used in the ENR formula. When single acting diesel
hammers are used, it is necessary to determine energy by multiplying ram weight times the
actual stroke. This requires field observation of the actual stroke. This approach is both
simple, conservative and almost universally accepted. The manufacturer's given energy
rating should not be used "blindly" in the ENR equation. Energy output should be verified
by measuring the stroke of single acting diesel hammers or by comparing the operations of
the hammer with the manufacturer's operating specifications.
One sometimes hears discussion about the "efficiency of a hammer". The efficiency is
merely the net kinetic energy normally delivered by a particular hammer to the pile cap
block divided by the potential energy of the hammer at the beginning of its stroke; or, in
other words, the percentage of the total potential hammer energy available at the top of the
stroke which is actually delivered by the ram of the hammer at impact. As has been men-
tioned above, engineers and inspectors use the rated energy of hammers as an indication of
the driving capability of the hammer. Manufacturers do not specify the amount of kinetic
energy delivered by a hammer at the head of the pile after undergoing energy losses. These
losses occur in transfer of energy through the driving system. Because all pile load bearing
formula are applied with safety factors, these energy losses, common to all hammers, are
usually accounted for in the load bearing formulas or are ignored. What you, as the
Engineer, must then ensure is that the accepted hammer on the job is operating properly
and is capable of producing the manufacturer's "rated energy" (or potential energy, at the
top of its stroke).
There are many factors that contribute to the loss of efficiency, such as wear, improper
adjustment of valve gear, poor lubrication, unusually long hoses, minor hose leaks, binding
in guides, and minor drops in steam or air pressure. All of the preceding illustrates the
necessity for the Engineer to have a working knowledge of hammer operations.