The basic purpose of this test is to evaluate pile static capacity, its structural integrity as well as hammer performance, pile stresses and soil characteristics, such as soil damping coefficients. On-site evaluation of the test results by a trained and experienced professional would determine if the pile is to be accepted or rejected.
The test is conducted by impacting the pile top with a drop hammer from a predetermined height. The impact produces a compressive wave that travels down the shaft of the foundation. Strain transducers and accelerometers are attached to diagonally opposite sides of the pile cap which respectively measure the strain and acceleration induced into the pile. Strain measurements are converted to force and acceleration records to velocities by a Pile Driving Analyzer®. Force and velocity measurements facilitate estimating soil resistance and its distribution.
The collected test data is analyzed and processed by computer software such as CAPWAP® [Case Pile Wave Analysis Program] to estimate total bearing capacity of a pile or shaft, as well as resistance distribution along the shaft and at the toe, producing the graphs shown opposite.
