The Becker Penetration Test (BPT), also known as Becker Drill Test, is performed with a diesel hammer that drives a double walled pipe into the ground. The test relates soil strength to the number of blows required to drive the last 300 mm of this casing. The BPT is used in coarse grained soils that are too hard to be tested with the Standard Penetration Test (SPT).
The energy output of the Becker Drill hammer varies. For this reason, the recorded number of blows must be adjusted for the energy of the hammer in order to yield a reliable assessment of soil strength. The Becker Penetration Test blow count can only be reliably used to assess soil strength if the end bearing component of resistance is known.
GRL Engineers use a Pile Driving Analyzer® (PDA) to measure the energy transfer to the top of the drill string from the diesel hammer used in the test. This data is analyzed by CAPWAP® to calculate the end bearing component of the driven Becker casing.