01 July 1997
(6) Cutting. The piles will be cut at the top to the proper elevation required by the design.
Damaged sections will also be cut from the pile before driving into the soil and splices made to restore the
pile to the required length.
(7) Spotting. The tip of the pile will be accurately positioned over the location stake for the pile.
The position can be checked by measuring the pile tip relative to two stakes driven 90 degrees apart.
(a) An accurate position of the pile can be made with fixed leaders and an adjustable spotter.
(b) A template is sometimes used to facilitate accurate positions.
(c) H-piles should be driven with their flanges in the correct orientation as shown by the plans.
(8) Alignment. Piles are aligned either vertically or at a specified batter.
(a) Alignment of vertical piles can be checked after spotting and before driving with a
carpenters level. The initial alignment is critical for piles driven through water or overburden and where the
final cutoff elevation is below the water or ground surface. The pile alignment should be checked
periodically while driving and on exposed lengths of not less than 5 feet.
(b) Alignment of batter piles can be assured with a wood template that is cut to the correct
batter angle. The template is held against the leader, pile, or the drill stem.
(c) The drill rig should be positioned on level ground. Timber mats can be used to support
the drill rig and to maintain a level orientation if the ground surface does not stable.
(9) Sequence of Installation. The displacement of the soil and vibration associated with the
driving compacts the soil. The penetration resistance at the design embedment depth will often be greater
than that of the piles driven earlier. Smaller spacings between piles increase compaction and the
penetration resistance. Driving should begin at the center of the pile group and proceed toward the ends of
(10) Heaved Piles. The compaction of the soil as a result of driving may cause the piles driven
first in the group to heave when later piles are driven. Piles that have heaved as a result of pile driving
should be restruck to determine that the penetration resistance is adequate and that the piles are driven to
the required embedment depth.
(11) Pile Driving System. The piles will usually be installed by either impact hammer or vibratory
driver. Results of the exploration program, wave equation analysis, driving of indicator piles with PDA, and
pile load tests will assist design of the pile foundation, determine the pile and length to be installed and the
driving energy. A minimum hammer size will be specified in the contract documents.
(a) Installation by impact hammers will require specification of the pile length and/or the
penetration resistance at the embedment depth.
(b) Installation by vibratory drivers will require specification of the embedment depth or
elevation of the pile tip. The specifications will usually require that an impact hammer be used to confirm
the penetration resistance, especially if the pile capacity is primarily from end bearing. Vibratory drivers are
most effective when installing friction piles and may not require confirmation of capacity by an impact
d. Contractor Experience. The work shall be performed by a contractor that specializes in the