Volume 6, Issue 4 (December 1983)
Reproducible SPT Hammer Impact Force with an Automatic Free Fall SPT Hammer System
Stress wave energy measurements were made to compare the performance of an automatic standard penetration test (SPT) hammer system with the free fall performance of a safety type hammer. It was found that the automatic free fall hammer and the safety hammer tested in free fall provide practically the same mean peak force at impact and the same mean driving energy. The coefficient of variation of measured stress wave energy during any test series of the automatic hammer system is relatively small and usually in the range of 1 to 2%.