(1)

Determine the design load Rd for a given pile in kN.

(2)

(a)

This value can be given in the design plans or computed by the methods referred to in

paragraph 2-11b.

(b)

The design load Rd can be multiplied by a factor of safety, according to the formula

Ru = N Rd

where

Ru = ultimate pile resistance, kN

N = factor of safety

= 2.0 when static load tests are required

= 2.5 when the pile driving analyzer and wave equation analysis are required

= 3.0 when only the wave equation analysis is required. (If a factor of safety has been

established for the piles elsewhere, then use that value.)

If values from both (a) and (b) are available, then use the greater of the two.

(3)

Divide the ultimate resistance value by the pile area using the formula

Su = Ru/Ap

where

with concrete piles or 62,000 kPa with steel piles for subsequent computational

purposes

As = pile cross-sectional area, m

(4)

Compute the minimum rated striking energy for the pile hammer for the particular pile at 4 blows

per centimeter (10 blows per inch.) The formula used depends upon whether the pile is steel or

concrete.

Er 10BPI = As Su/ (70.08 e(-Su/25449) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concrete Piles

Er 10BPI = As Su1.62/58500 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Steel Piles

where

Er 10BPI =

minimum hammer rated striking energy at 4 blows per centimeter (10 blows per inch) of

resistance, kJ

Figure 2-1a. Preliminary Method for Sizing Hammers for Concrete and Steel Piles, SI units

(after Florida DOT Specification, Section 455) .

2-5

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