Sonic Echo / Impulse Response (SE/IR) Testing

Sonic Echo and Impulse Response (SE/IR) testing are non-destructive methods used to assess the integrity and length of deep foundation elements.

These methods are particularly effective for:

• Drilled shafts
• Driven piles
• Auger-cast piles
• Accessible shallow wall structures, such as bridge abutments or piers

Both concrete and wood foundations can be evaluated using SE/IR. Certain steel piles, like round pipe piles, may also be tested. However, H-piles typically do not respond well due to high energy damping from their shape and surface area.

How It Works

SE/IR tests involve applying a mechanical impact (via an impulse hammer) to the top of the pile or foundation. A nearby receiver (typically a geophone or accelerometer) records the resulting wave responses.

• Sonic Echo (SE):
  • Evaluated in the time domain
  • Measures the time delay of reflected compression waves
  • Useful for estimating pile length and identifying defects
• Impulse Response (IR):
  • Evaluated in the frequency domain
  • Focuses on impedance changes along the shaft
  • Provides data on stiffness, mobility, and potential anomalies