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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
Static Pile Load Testing and Dynamic Pile Monitoring
8-4
Dynamic Pile Monitoring
Along with Static Load Testing, personnel from the Foundation Testing and Instrumenta-
tion Section are assigned the responsibility for performing Dynamic Pile Monitoring on
Caltrans projects. In most cases Dynamic Pile Monitoring is performed in conjunction with
Static Pile Load Testing.
The dynamic monitoring refers to the use of a device called the Pile Driving Analyzer
(PDA). The PDA consists of a portable computer which collects and analyzes strains and
accelerations measured by instrumentation attached to the pile being driven.
Dynamic monitoring of piles is usually performed during the installation of the test and/or
anchor piles to be used for the Static Load Test. Piles to be monitored, using the PDA, are
usually driven to a predetermined distance above the specified tip before the monitoring
begins. At that time, the Contractor must stop driving and allow personnel from the
Foundation Testing and Instrumentation Section to attach the necessary instrumentation to
the pile. This instrumentation is attached approximately 1
1
/
2
pile diameters from the top of
the pile. The Contractor then resumes driving the pile but only for a few blows. This allows
the PDA Operator to ensure that the instrumentation is attached correctly and that the data
is being transmitted to the PDA computer. The Contractor then resumes driving the pile
until the tip of the pile is one foot above the specified tip elevation. Once all the monitored
piles are driven to this elevation, they are then allowed to “set-up”, usually overnight. On
the next day the instrumentation is once again attached for a retap. Before the retap, the
pile must be marked over a one foot length, in increments of one tenth of a foot. Again, the
pile is hit for a few blows to ensure proper instrumentation connection. The pile is then
driven for the remainder of the one foot length.
Before the pile monitoring begins, the PDA operator inputs parameters related to the
physical characteristics of the pile. Data is also entered to describe the surrounding soil and
its damping resistance.
The PDA is capable of analyzing the stress wave produced by each blow of the hammer
during the driving operation. By analyzing the shape of the wave trace, the PDA is able to
measure pile stresses generated during driving. Information retrieved by the PDA is used to
predict a pile’s static load capacity.
The PDA very accurately measures the energy delivered to the pile during driving. This
energy rating can be compared to the manufacturer’s rated value to provide an indication
of the hammer’s actual performance efficiencies. Low or unusual delivery of energy to the