Energy ConsiderationsIf we take PDA measurements….

Energy Concepts

• Potential Energy• Rated Energy• Kinetic Energy (Hammer Efficiency)• Transferred Energy (ENTHRU)

…we can calculate the Transferred Energy

WR

h

ER = WR hManufacturer’s Rating

WR

Max ET = ∫F(t) v(t) dt(ENTHRU)

ηT = ENTHRU/ ER (transfer ratio or efficiency)

Measure Force, F(t)Velocity, v(t)

Statistical Summaries Transferred energy ratios at End of Driving

Statistical Summaries Transferred energy ratios at End of Driving

Statistical Summaries Transferred energy ratios at End of Driving

Statistical Summaries Transferred energy ratios at End of Driving

Energy

• Three types of energy:• Potential or rated energy (mgh)

• Friction inside hammer• Inclination

• Kinetic or impact energy (mv2/2)• Hammer cushion• Helmet • Pile cushion

• Transferred energy or ENTHRU (PDA)• Pile length• Resistance