What is PDA Testing?


Dynamic Load Testing or PDA testing, is a fast, reliable and cost effective method of evaluating foundation bearing capacity. SSG can perform Dynamic Load Testing on driven piles, drilled shafts, auger-cast piles, micropiles, helical piles, and other cast in place foundations. It is often possible to conduct several dynamic load tests in a single day.

In addition to bearing capacity, Dynamic Load Testing provides information on resistance distribution (shaft resistance and end bearing) and evaluates the shape and integrity of the foundation element.

The Dynamic Load Test involves a substantial ram mass that impacts the top of the foundation and causes it to experience a small permanent set. Prior to the test, SSG recommends an adequate hammer or drop weight. SSG supplies one of its dynamic loading systems. SSG's line of devices are designed to activate a large range of test loads, and offer a low cost alternative to static testing of any deep foundation, from micropiles to large shafts.

Accelerometers and strain transducers attached to the foundation measure force and velocity as the drop weight hits it. Instead of strain transducers, SSG may also use a force transducer, which speeds up the test and in certain cases may yield more accurate force measurements. SSG analyzes data in real time with thePile Driving Analyzer® (PDA) dynamic testing system. Data is further analyzed with the CAPWAP® software. SSG engineers furnish a detailed report for each Dynamic Load Testing project that includes a simulated static load test in the form of a calculated load-set curve.

Dynamic Load Tests are standardized by ASTM D4945-12 Standard Test Method for High-Strain Dynamic Testing of Piles. The test may also be configured to meet the requirements of the Rapid Load Test standardASTM D7383 provided an adequate ram is available.