EI 02G001
CEMP-E
01 July 1997
(5)
Recompute the ultimate unit pile resistance using the formula
Su' = 3 Rd/As
where
Su' =
ultimate pile resistance per unit area for 8 blows
per centimeter (20 BPI) case, kPa. This value
should not fall below 6200 kPa with concrete piles
or 62,000 kPa with steel piles for subsequent
computational purposes
(6)
Compute the minimum rated striking energy for the pile hammer for the particular pile at 8 blows
per centimeter (20 blows per inch.) The formula used depends upon whether the pile is steel or
concrete.
Er 20BPI
= Su' As/(100.78 e(-Su'/22989)) . . . . . . . . . . . . . . . . . . . . . . . Concrete Piles
Er 20BPI
= As Su'1.68/165486 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Steel Piles
where Er 20BPI
= minimum hammer rated striking energy at 8 blows per centimeter (20 blows per inch)
of resistance, kJ.
(7)
The minimum rated striking energy for the hammer is the greater of Er 10BPI and Er 20BPI.
(8)
Compute the minimum ram weight. Having computed the minimum rated striking energy for the
hammer, one or more hammers can be selected as possible candidates for driving the pile. The
equivalent stroke should be then computed by the equation
Seq = 102 Er/ms
where
Seq
=
equivalent stroke, m. This value should not exceed 2.44m for subsequent
computational purposes
Er
=
rated striking energy of the hammer, kJ
ms
=
ram mass of the hammer, kg
(9)
The minimum ram mass for each hammer can be computed for concrete and steel piles by the
equation
msmin
= 17659 As/(Seq) . . . . . . . . . . . . . . . . . . . . . . . . . . . Concrete Piles
msmin
= 161068 As/(Seq) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Steel Piles
where
msmin
=
minimum ram weight, kg
A hammer should be rejected if its ram weight is less than the minimum ram weight, and other hammers
considered until one has been selected with a sufficiently large ram.
Figure 2-1a. (Concluded)
2-6
Previous Page
