01 July 1997
determine driving stresses. Those stresses should be compared with the pile' maximum dynamic stress
criterion, and the pile and/or hammer should be altered to limit these stresses.
(b) Jobsite Control. Once the hammer has been selected and the installation of the piles is
about to begin, a pile load test program should be conducted to verify any hammer selection analysis.
During driving, the methods described in chapter 4 should be adhered to as well.
(c) Quick Method (Concrete and Steel Piles). For concrete and steel piles, if a rough estimate
is desired, a method is presented in figure 2-1a in metric units and in figure 2-1b in English unit, Preliminary
Method for Sizing Hammers for Concrete and Steel Piles, Metric Units (after Florida DOT Specification,
(c) Wood Piles. A pile driving hammer for wood pile shall be rated by the manufacturer from
7,200 to 22,500 foot-pounds to deliver a minimum of 35 percent of its energy to the pile. The Engineering
News Formula can be used for preliminary determination of drivability.
(3) Vibratory Hammers. At this point, there is no accepted method to determine either the
drivability or the bearing capacity of a pile driven by vibration. In the absence of such a method, figure 2-2a
(metric units) and figure 2-2b (English units) show a guide for determining whether or not a particular pile
can be driven into a particular soil.