Pile Testing: static, dynamic and integrity tests
Pile testing confirms that piles carry their design loads with acceptable settlement and are structurally sound. Static load tests measure load and settlement directly; dynamic load tests estimate capacity from the stress wave under a hammer blow; and low-strain integrity tests check piles for defects.
When the test is used
Typically used for…
- Preliminary test piles to confirm design assumptions before production.
- Working pile tests to verify installed piles.
- Integrity screening of large numbers of piles.
- Tension and lateral load tests where required.
Limitations
- Static tests need substantial reaction (kentledge or reaction piles) and time.
- Dynamic test capacity is an estimate that depends on signal matching and calibration.
- Low-strain integrity tests detect major defects but do not measure capacity, and reliable interpretation depth is limited.
The test type, number and locations are agreed with the consultant for each project.
How the test works
In a static load test, a jack loads the pile in steps against kentledge or reaction piles. Each step is held while displacement gauges on an independent reference beam record settlement.
In a dynamic load test, a drop weight strikes the pile head while strain and acceleration sensors record the stress wave; analysis estimates the mobilised capacity. In a low-strain integrity test, a small hammer blow sends a wave down the pile, and its reflections reveal changes in section or defects. In larger bored piles, cross-hole sonic logging checks the concrete between tubes cast into the pile, over the length of the tubes.
Test planning inputs
- Design loads and test loads.
- Type of test, number and location of piles.
- Reaction system and loading procedure.
- Acceptance criteria for settlement or capacity.
- Applicable standard.
Calibration and equipment checks
- Jack, load cell and gauge calibration checked.
- Sensor calibration for dynamic tests.
- Concrete age and pile head preparation checked before testing.
Test execution controls
- Load increments and hold periods as per the procedure.
- Readings continued until settlement-rate criteria are met.
- Reference beams independent of the reaction system.
- Signal quality checks for dynamic and integrity tests.
- Test records for every pile.
Interpretation and reporting
The test plan, the raw record and the interpretation are kept separate, so it is always clear what was specified, what was measured and what it shows.
What is specified
Test loads, procedure and acceptance criteria agreed with the consultant.
What was measured
Load-settlement records, or dynamic and integrity signals, for each pile.
What it shows
Capacity, settlement behaviour and integrity assessed against the criteria.
Deliverables
- Test procedure and pile selection
- Calibration certificates
- Load-settlement curves
- Dynamic analysis and signal-matching reports
- Integrity test reports
- Summary of results against criteria
Common questions
What is the difference between static and dynamic pile tests?
A static test loads the pile slowly and measures settlement directly. A dynamic test estimates capacity from the stress wave produced by a hammer blow.
What does a pile integrity test detect?
Major defects or changes in the pile's cross-section. It does not measure capacity.
How many piles are tested?
The number is set by the project specification and the applicable standard, and agreed with the consultant.
Discuss the testing your project needs.
Share the project stage, the ground conditions and the specification or acceptance criteria.