PDA Testing on Bored Piles / Micro Piles
DTS own and operate the PDA/CAPWAP system of testing developed by Pile Dynamics Inc, Ohio, USA and has been in use for more than 20 years. Pile instrumentation and monitoring will be performed according to the ASTM standard D4945-17.
PDA procedure applies an axial impact force with a pile driving hammer, causing high strain at the inclined deep foundation unit and measures the subsequent force & velocity response of that deep foundation unit. Measurements of the force and velocity signal induced in the pile during pile driving are collected by strain and accelerometer transducers, which are fixed near the pile head (at least 1.5 diameter away from pile top).
For each blow struck to the pile the PDA signal processor conditions the output from these transducers and passes it to the processing section of the PDA. The PDA has an in-built program, which calculates over 30 pile driving variables based on the data obtained from each blow.These variables include maximum pile top force, displacement and velocity, estimates of pile static and dynamic capacity.
On completion of all field work, a final report covering all aspects of the pile monitoring and analysis work will be prepared. This report will incorporate results of the PDA monitoring, and results of all CAPWAP computer analyses. The results of the CAPWAP analyses will be compared to the PDA results and correlations will be drawn between the CAPWAP data and the PDA field monitoring results.
Results from PDA test will be calibrated against the static load test results if results are available, to obtain a better correlation and comparison with the static.
Results which can be obtained in report are as follows: –
- Static capacity of piles (compression or tension) mobilized.
- Simulated load settlement curve under static load.
- Pile integrity (any defects, necking, crack or any irregularities in pile shaft)
RECOGNITION OF PDA TEST
PDA test is well recognized in the following international standards: –
- ASTM (American Standard of Testing Materials) standard D4945-17
- ICE Piling Specifications (UK)
- BS8004 (British Standard Foundation code – 7.5.2)
- Canadian Foundation Engineering Manual (1992 – Canadian Geotechnical Society).
PDA Model PAX
PDA Test for Bored Pile