Develop The Capacity/Resistance Table
This page will enable you to develop the capacity/resistance table vs. blow count for two widely used dynamic formulae:
- Engineering News Formula: The first dynamic formula to achieve wide currency (in the U.S. at least,) this formula dates back from around the time Vulcan hammers were first introduced. It is still found in many pile driving specifications, especially those for wood piling.
- Gates Formula: A more advanced formula than the EN formula, it is recommended by the FHWA as an initial estimate of hammer size.
Use of these formulae is discussed in detail in the Vulcan Hammer Guide to Pile Driving Equipment. All energies used are the rated striking energy of the hammer. By clicking on the hammer size that you need you will be taken to a table.
Important note: all results are in kips. EN formula results are traditionally reported in U.S. Tons; comparison needs to be made on this basis.