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 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 PDA is available in two models. The PAK is self contained and displays results in real time on its color LCD screen. Its 8 channels of data acquisition make it suitable for testing large shafts. The PDA-W and CAPWAP^® software programs can both run in the PAK itself.

The light and compact PAL-R (U.S. Patent Number US 6,301,551 B1) gives the engineer the option of avoiding travel to the job site, since it allows following the dynamic load test from a remote computer. A site crew can be trained to set up the sensors and the PAL-R, allowing an engineer located either onsite or elsewhere to run the PDA-W software and follow the test via a cell phone connection.

The PDA-W software calculates its results from velocity and force signals obtained by accelerometers and strain transducers attached to the foundation.

CAPWAP analyses of PDA data is essential for a dynamic load test. It provides the resistance distribution of 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 PDA conforms to ASTM D4945 and many other codes and specifications.