per blow have been attained. If a pile fails to reach the "calculated" tip
elevation or if a pile reaches the "calculated" tip elevation without
reaching the required driving resistance, the Contractor shall notify the
Contracting Officer and perform directed corrective measures.
3.1.2
Pre-Drilling
[Pre-drilling of piles will not be permitted] [Pre-drilled starter holes
may be required for penetrating through extra hard natural strata or rolled
fills. Drilling or augering will be permitted only with the approval of
the Contracting Officer. The hole shall be [_____] mm inches less in
diameter than the diagonal dimension of the pile and shall be backfilled
with granular material after installation of the pile. The drilling or
augering shall not be deeper than required to bypass the obstructing layer].
3.1.3
Jetting of Piles
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NOTE: Jetting generally will not be permitted for
piles dependent on side friction in fine-grained
low-permeability soils (high clay or silt content),
where considerable time is required for the soil to
reconsolidate around the piles, for piles subject to
uplift or lateral forces, for piles adjacent to
existing structures, or for piles in closely spaced
clusters unless the load capacity is confirmed by
test.
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[Jetting of piles will not be permitted] [When jetting of piles is
permitted by the Contracting Officer, jetting shall be discontinued at a
depth approximately 1.5 m 5 feet above the "calculated" tip elevation; the
remaining penetration shall be achieved by driving. Before starting the
driving of the final 1.5 m 5 feet, the pile shall be firmly seated in place
by the application of a number of reduced-energy hammer blows].
3.1.4
Long Piles
Pile lengths of [_____] m feet or more shall be handled and driven
carefully to prevent overstress or leaning from a true position. The
pile-driving rig shall have sufficiently rigid supports so that the leads
remain accurately aligned. Templates or guide frames shall be erected at
or close to the ground or water surface.
3.1.5
Splices
Field splices shall be avoided for lengths under 18 m 60 feet. When
authorized by the Contracting Officer, splices shall be of the full
penetration butt-weld type. Unless otherwise authorized by the Contracting
Officer, only one splice will be permitted per length of pile. Splices
shall be designed and constructed to maintain the true alignment and
position of the pile sections. Splices shall develop the full strength of
the pile in both bearing and bending. Proprietary prefabricated splicer
sleeves may be used upon prior approval by the Contracting Officer.
3.1.6
Welding
Shop and field welding, qualification of welding procedures, welders, and
welding operators shall be in accordance with AWS D1.1/D1.1M.
SECTION 02456A
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