Acoustic continuity testing - Vroom Foundation Technology
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Acoustic continuity testing

In order to demonstrate the strength of an in-situ formed concrete pile, its integrity is tested acoustically once the concrete has cured. We take readings using the IFCO/TNO-Profound calibrated measuring system.

It is possible to verify the integrity of driven piles. Acoustic testing allows us to identify discrepancies/faults. By using computer programs and basing information on soundings and the soil profile, we can calculate whether any discrepancies could have an adverse impact on the bearing capacity. On request, Vroom Funderingstechnieken (Vroom Foundation Technology) can take ultrasonic readings of all piles, verifying the integrity of each one.

Method

During acoustic testing a plastic mallet is used to give a blow to the pile cap, which releases a sound wave through the pile. An acceleration transducer converts the oscillations from the pile shaft and transmits them to a processor unit, filtering and amplifying the signal. The shock wave runs through the pile length-ways, as far as the pile toe, then back up to the pile cap. How long this takes depends on the short-term elastic modulus and the density of the pile material (concrete).  The speed with which the shock wave travels through the piles (for in-situ concrete piles) is between 3700 and 4000 m/sec, and for pre-fab concrete piles between 4000 and 4400 m/sec.