Commonly referred to as PDA testing – uses measurements of pile strain and acceleration during pile driving to gather useful information for the pile and piling hammer.
Generally, PDA testing is used to:
- Estimate mobilized pile capacity including shaft and end-bearing resistance
- Measure pile stresses to optimize driving criteria and minimize risk of pile damage
- Evaluate hammer efficiency
- Assess pile integrity
TREK Geotechnical offers full-service dynamic load testing, from pile preparation and sensor installation to test data analysis and reporting. We use industry-leading technology and software, including the Pile Driving Analyzer® (PDA) and Case Pile Wave Analysis Program® (CAPWAP).
We understand that construction schedules are tight, delays are costly, and PDA testing results are often on the critical path during construction. TREK has a proven track record of providing quality testing services, adapting quickly to serve our client’s needs, and delivering timely results.
We adjust our testing services on a project-by-project basis to meet each client’s specific needs; some projects require CAPWAP analysis on each pile and formal reporting, while others may only require raw field results and informal reporting. TREK’s PDA testing services are flexible and responsive to our client’s requirements.
From an owner’s perspective, dynamic load testing can result in cost savings in the form of a more efficient foundation design which takes advantage of building design codes that reward dynamic load testing with a higher resistance factor. For the designer, PDA is a powerful tool to confirm that pile behaviour in the field is consistent with the foundation design, and provides an opportunity to adjust installation methodology in real time to meet the requirements of the foundation design.
From a contractor’s perspective, PDA testing needs to be done efficiently to maintain a high level of productivity; TREK understands this, and efficiency is a top priority in testing and delivering results. However, PDA testing also benefits the contractor as a means of documenting compliance with project specifications relative to piling hammer energy, refusal sets, capacity, and pile stresses.
These benefits were evident in a bridge construction project here in Manitoba, which included PDA testing of steel H-piles at the abutments and open-end pipe piles at the piers. The testing was specified to confirm that the refusal criteria proposed in the geotechnical report was acceptable such that piles were not over-stressed during driving, but also reached the target capacity at refusal.
A typical refusal criterion of 10 blows per 25 mm of pile penetration was specified in the geotechnical report, but at one abutment, piles were reaching their full installation depth at only 4 blows per 25 mm. Using PDA testing, TREK was able to confirm that the hammer was delivering an appropriate amount of energy to the piles, that pile stresses were acceptable, and that the H-piles installed to the design tip elevation met the project-specific capacity requirements at 4 blows per 25 mm.
This information was gathered during pile installation and allowed for real-time adjustments to pile installation procedures that resulted in significant cost savings relative to the alternative, which in the absence of PDA testing would have been to splice pile extensions and drive until the refusal criteria laid out in the geotechnical report was met.