High Strain Dynamic Test (PDA)
Test reference Standard: ASTM D 4945-17 – Standard Test Method for High-Strain Dynamic Testing
of Deep Foundations
Low Strain Dynamic Test (PIT)
Test reference Standard: ASTM D5882 – Standard Test method for Low Strain Impact Integrity Test
of Deep Foundations
ABOUT THE TEST
The Pile Integrity Tester (PIT-Q) is a reliable, non-destructive testing device designed to evaluate the structural integrity of various deep foundation elements. It is suitable for bored piles, diaphragm walls, steel piles, drilled displacement piles, driven concrete or timber piles, and concrete-filled pipes. Utilizing wave equation-based methods, the PIT-Q performs Low Strain Integrity Tests—also known as Low Strain Dynamic Tests—to ensure that foundations are free from significant structural defects.
In Singapore, the Land Transport Authority (LTA) mandates the use of PIT for pile testing in buildings with 10 storeys or more. As part of the Pile Integrity Testing requirements, low strain impact integrity test must be conducted on a minimum of two piles or 2% of the total number of working piles—whichever is greater.
Table 1 – LTA Civil Design Criteria for Road and Rail Transit Systems, E/GD/09/106/A2, Table 6.3 – Minimum requirements for Testing of Deep Foundation Elements
EQUIPMENT AND TECHNOLOGY
Engineered for single-operator use and fully compliant with ASTM D5882 and other international standards, the PIT-Q can detect critical issues such as major cracks, pile necking and voids or soil inclusions.
Its versatility allows for testing of piles that are part of existing structures, such as bridge or tower supports, and it can also assist in determining pile length. The PIT-Q’s fast and efficient testing process often enables the inspection of every pile on a job site without requiring prior planning, making it an ideal solution for both new construction and retrofit projects.
The testing procedure involves attaching an accelerometer to the top of the pile or shaft and striking it with a handheld hammer. This impact generates a stress wave that travels down the foundation and reflects back when it encounters a change in cross-section or reaches the pile toe. The accelerometer records the wave’s behavior, and the PIT-Q displays the data as curves that reveal any significant structural changes. A clear reflection from the pile toe at the expected time typically indicates a defect-free pile, while anomalies in the wave pattern may signal the presence, size, and location of defects along the shaft.