Pile Integrity Testing
Pile Integrity Testing, also known as Sonic Echo Testing and low strain dynamic testing is used to determine the length and integrity of deep foundations and driven piles. The method works well in concrete or timber foundations that are not excessively slender. In order to perform the test, the top (preferably) or side of the foundation must be accessible. An accelerometer is placed on the top of the foundation and a lightweight hammer is used to impact the top the foundation adjacent to the accelerometer. The impact produces a compression wave that travels down the foundation or pile at a constant wave speed. Changes to the foundation, such as a reduction in diameter, a crack, a void, or the end of the foundation produce wave reflections. The amplitudes and travel times of the reflected waves are recorded by the accelerometer. From this data, the length of the foundation or pile can be calculated. While the method will be able to detect a large crack or deformity in the foundation, the method will not be able to image the end of the foundation if such a crack is present. This method is covered under ASTM D5882-00 - Standard Test Method for Low Strain Integrity Testing of Piles.