How accurate is the Pile Integrity Tester (PIT) when used for determining foundation lengths?


The accuracy of foundation length is dependent on the accuracy of the wave speed. Since the wave speeds for good quality concrete vary between 3500 m/s (11,500 ft/s) and 4500 m/s (14,500 ft/s) on low strain tests like those performed with the PIT (and the Acoustic Concrete Tester (ACT) - see Question 1018, if an average wave speed of 4000 m/s (13100 ft/s) is used then a maximum variation of plus or minus 12.5 % is possible.