Pile Integrity Test can be used to determine the integrity of piles. The method works best for long structural component such as driven concrete piles, cast-in place concrete piles, concrete filled steel pipe piles, timber piles, structural columns. The method works based on measuring and analyzing the velocity (required) and force (optional) response of pile. A hammer (regular or instrumented) is used to impact the pile surface and induce acoustic waves (WATCH: How PIT is Performed?). The test may not identify all imperfections, but generally can identify major defects within the effective length. In this article, we will review some of the main applications and limitations of pile integrity test. The test has been standardized as the ASTM D5882: Low Strain Impact Integrity Testing of Deep Foundations.
Applications of Pile Integrity Test
1. Evaluate unknown length of piles, or elements;
2. Evaluate pile cross-sectional area and length;
3. Determining the integrity and continuity of piles;
4. Evaluate consistency of pile material
Pile Integrity Test (PIT) provides useful information about the above-mentioned aspects of piles. However, the method has certain limitations, some of which are inherent. The following section summarizes the main limitations of the pile integrity method.
Limitations of Pile Integrity Test
1. Pile Integrity Test does not provide any information on the load bearing capacity of piles and deep foundations.
2. Integrity Testing cannot be conducted over pile caps.
3. Integrity testing of cross sections below a major crack (that crosses the entire cross-sectional area) is not possible.
4. This test is not effective in piles with highly variable cross sections
5. It is not effective in evaluating sections of piles below cracks that crosses the entire cross-sectional area of the pile.
6. Pile integrity is generally not suitable for testing steel sheets, H-section, or unfilled pipe piles.
7. When the toe reflection is not evident, integrity evaluation may not be conclusive.
8. In some cases, it is difficult to distinguish the soil response, and the (pile) toe response.