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The PDA is the most widely employed system for Dynamic Load Testing in the
world. It can assess the capacity of multiple drilled shafts, cast-in-place, continuous flight auger or
bored or driven piles in a single day.
PDA tests, or High Strain Dynamic Tests, simply require a drop weight (see examples) to
impact the shaft, and that the top of the foundation be cushioned by a few thin plywood sheets.
The light and battery operated PAX is available with 4 or 8 channels of data acquisition;
8 channels are important for testing cast-in-place piles and drilled shafts. The PAX gives the engineer the
option of being present for the test or avoiding travel to the job (SiteLink PDA Testing).
When the engineer is present for the test the PAX runs in local mode and displays all test data and results on its LCD screen.
When only the PAX is on location a field crew sets up the test and the PAX transmits test
data via a broad band internet connection, while an engineer located elsewhere follows the test in real
time.
The PDA software calculates its results from velocity and force signals
obtained by accelerometers
and strain transducers attached to the foundation. These sensors may be Traditional (transmit data via cable) or Smart (transmit data
using Wireless Transmitters).
CAPWAP® analysis of PDA data is
essential for a Dynamic Load Test. It provides the soil resistance distribution along the foundation and simulates
a static load test. Extensive correlations between CAPWAP-simulated and actual static load tests have proven the
reliability of this method of determining foundation capacity.
The PAX is patented under the Remote Pile Driving Analyzer US Patent No. US 6301551.
The PDA is also available in the model PAK, which features a keyboard. Both PDA models conform to
ASTM D4945 and many other codes and specifications. The PDA software suite, consisting of PDA-W,
PDIPLOT and PDICURVES, outputs reports that satisfy ASTM 4945 requirements.
The Pile Driving Analyzer may also be used to determine the energy transferred to SPT rods.
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