Parallel seismic test

Parallel Seismic Test

The Parallel Seismic Test is a non-destructive test used to determine the pile length when the details of the foundation are no longer available, or when the constructed pile length is questionable. Test equipment consists of accelerometers, an impact hammer, and the data acquisition system (DAQ). The hammer is used to create an impact at connecting point between the structure, and the pile or the foundation (more effective with the direct impact at the top of the pile itself). At the point of impact, waves will firstly be detected by the accelerometer and displayed by DAQ. Next, the waves are transferred along the pile, and shear waves will be propagating through the soil to the receiver accelerometer in a PVC pipe located 1.5 m from the pile cap. The test is conducted at every 1m receiver intervals throughout the entire length of the PVC pipe.

Any diffraction or change in slope that occurs in the data as a result of the pile tip acting as a point diffractor and a reflector indicates the end of the pile. Thus, the pile length can be determined.

Please find below a sample of the test results from a past project conducted by RE using the Parallel Seismic Test.

Pile depth vs wave travelling time