SPT Energy Calibration consists of measuring the energy transferred by the Standard Penetration Test (SPT) hammer to the SPT rod. GRL Engineers take these measurements with the Pile Driving Analyzer® (PDA) and using an SPT rod instrumented with strain gages and accelerometers. GRL Engineers may also estimate soil setup by conducting a torque test on the instrumented SPT rod.
The Standard Penetration Test (SPT) is a widely used geotechnical test used to estimate soil strength. A SPT hammer drives a split barrel sampler at the bottom of a drive rod and recovers soil samples. The number of blows required to drive the last 300mm (12 inches) is the “N value”, and indicates soil strength. Several different types of SPT hammers are used to perform SPT tests, and this influences the N value.
The American Society for Testing and Materials (ASTM) recommends standardizing the measured N value by multiplying it by the ratio between the measured energy transferred to the rod and 60% of the theoretical potential energy of the hammer resulting in the N60 value. This compensates for widely variable efficiencies from different SPT hammer types and therefore improves the reliability of the estimates obtained from the test.
Source: GRL Engineers
Source: GRL Engineers
Pile Dynamics recently released a redesigned system for SPT hammer calibration. Both the hardware o...
At the conclusion of the webinar attendees will be able to describe the principles of data collecti...
To determine the mechanical properties of soil, an engineer can rely on both CPT and SPT methods. L...
When: September 13, 2016 Who should attend: Geotechnical, structural and construction engineers; c...
When: September 15th, 2015 Who should attend: Geotechnical, structural and construction e...
Introduction A standard penetration test (SPT) is one of the most popular in-situ tests carrie...
At the conclusion of the webinar attendees will be able to: Describe the principles of data colle...
After this webinar you will be able to: Describe the principles of data collection and interpret...