3.3.1.2
Blow Count and Penetration Depth
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NOTE: Drive the sampler with blows from a 64 kg 140
pound hammer falling 762 mm 30 inches until either
457 mm 18 inches have been penetrated or 100 blows
have been applied.
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Perform the tests after caisson bottoms have been cleaned. Minimum blow
count shall be [_____] per m [_____] per foot. [Penetration tests shall be
taken to a depth of [_____] m [_____] feet below the bearing elevation.
The Contractor shall obtain and retain jar samples, as directed by the
Contracting Officer.]
3.3.1.3
Failure of Test
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NOTE: An additional 305 to 610 mm one to two foot
drilling of shaft may be necessary.
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If the minimum blow count is not obtained, drill the shaft an additional
[_____] mm [_____] feet and rerun the penetration test.
3.3.1.4
Test Approval
The Contracting Officer will approve tests and authorize subsequent
concrete placement or initiate redesign procedures.
3.3.2
Proof Test Holes
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NOTE: Require proof testing if the soundness of
rock below the caisson bearing level is unknown.
Indicate location of each caisson to be proof tested.
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3.3.2.1
Soundness of Rock Test
After excavation, proof test the soundness of the rock below the caisson
bearing level by percussion or rotary core, drilling one hole in each
caisson in locations indicated.
3.3.2.2
Drilling
Holes shall be 51 mm 2 inch diameter and drilled with a uniform downward
pressure to a depth below the bearing level equal to the design caisson
shaft diameter but to a minimum of 1.2 m 4 feet.
3.3.2.3
Drilling Records
Record penetration time for successive 152 6 inch increments, noting
conditions encountered.
3.3.2.4
Test Approval
The Contracting Officer will approve test holes and authorize subsequent
concrete placement or initiate redesign procedures.
SECTION 02468N
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