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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
7-32
pile flexibility. No pile driving formula accounts for all energy losses, and the major
difference between formulas is which losses each considers.
There are many different (at least 450) pile driving formulas, the more notable of these
being the Gates, Hiley, Pacific Coast Uniform Building Code, Janbu, and the ENR. Refer to
Appendix E for examples.
Section 49-1.08 of the Standard Specifications requires that the bearing value of driven
piles be determined using the ENR formula.
This formula was developed prior to the year 1895 by Arthur Mellon Wellington, the general
manager and part owner of Engineering News-Record. Wellington developed it for timber
piles driven with a drop hammer. The formula was modified at a later date with the advent
of steel and concrete piles and more sophisticated hammers. Both the original and the
updated versions are given in the Standard Specifications. The ENR formula is the most
commonly used in this country.
Section 49-1.08 of the Standard Specifications gives two different variations of the ENR
formula. One of these is used for drop hammers and the other is used for single or double
acting hammers or diesel hammers (Refer to Appendix E for a derivation). Of these two, the
most commonly used is the diesel hammer formula and is as follows:
P E
s
= +
2
01
.
where:
P = safe load in pounds
E = manufacturer’s rating for foot-pounds energy developed by the hammer
s = penetration per blow in inches
Inspection of the diesel hammer formula shows that it is an energy conservation equation
with an additional 0.1 inch term and a reduction factor of 6. The intention of the 0.1 inch
term is to account for elastic rebound and to encompass energy losses in the piling system.
The reduction factor of 6 relates the result of the ENR formula to a safe (working stress)
load. Ideally, this would mean a safety factor of 6. Comparisons of safe pile loads predicted
with the ENR formula and measured capacities from statically load-tested piles have shown
the factor of safety to vary greatly. Actual factors of safety have been shown to range between
0.8 and 30 when this formula is used.