more than one percent of their exposed length above the mudline. Check
piles for heave. Redrive, to the indicated elevation, piles found to be
heaved.
3.1.5
Jetting and Predrilling Holes
If predrilled holes are used, the diameter of the hole shall not exceed the
diagonal dimension of the pile and the hole shall be kept open until the
pile is inserted and advanced to the bottom of the hole. Piles shall be
installed in holes immediately after predrilling to minimize the potential
for sloughing and collapse of the hole. Jetting of the pile to obtain
penetration is permitted. Discontinue jetting or predrilled hole at a
depth of 1.5 m 5 feet from the indicated tip elevation, and achieve the
remaining penetration by driving. Before starting the driving of the final
1.5 m 5 feet, firmly seat the piles in place by the application of a number
of reduced-energy hammer blows. The Contractor shall arrange to provide an
ample supply of water at adequate pressure for effective jetting. The use
and details of jetting or predrilled holes shall be approved by the
Contracting Officer.
3.1.6
Splices
Splicing of piles is not permitted.
3.1.7
Buildup
Buildups are not permitted.
3.1.8
Pile Cutoffs
Cut off piles with a smooth level cut using pneumatic tools, sawing, or
other suitable methods approved by the Contracting Officer. The use of
explosives for cutting is not permitted.
3.1.9
Patching
a.
Embedded Lifting Loops. Provide a 25 mm one inch minimum conical
depression around embedded lifting loops. Cut off lifting loops
at bottom of depression and patch depression with epoxy mortar.
b.
Pile Butt. Apply 25 mm one inch thick layer of epoxy mortar cover
over exposed prestressing strand on pile butt after driving.
3.2
EQUIPMENT
3.2.1
Pile Hammers
Furnish a hammer having a capacity at least equal to the hammer
manufacturer's recommendation for the total weight of pile and character of
subsurface material to be encountered. Obtain the required driving energy
of the hammer, except for diesel hammers, by use of a heavy ram and a short
stroke with low-impact velocity. The pile hammer shall be capable of
operating at a reduced energy level (1/2 to 2/3 of rated energy level)
during seating of the piles in preformed holes and when driving through
soft or loose materials. The driving energy of the hammer, at final
driving, shall be not less than 40.650 Joules 30,000 foot-pounds.
At
final driving, operate the pile hammer in accordance with the
manufacturer's recommendation. At final driving, operate diesel-powered
hammers at the rate recommended by the manufacturer for hard driving.
SECTION 02395
Page 19
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