| Vibrex Cast-In-Situ Pile
Execution
stages of a Vibrex pile
- A steel
tube with a watertight steel shoe (bottom plate) is driven into the
ground un-til the required depth is reached, or until suffi-cient resistance
to penetration is encountered.
- After
checking the quality of the pile shaft (tube is inspected regarding
alignment or water tightness), the reinforcement cage is placed and
then concrete is poured.
- The special
Fundex vibrator is clamped to the tube. The tube is vibrated loose and
is extracted thereafter. Due to tube vibrations, the concrete is in
a liquefied condition and will flow out of the tube. A pile shaft of
high quality will be formed during the extrac-tion of the tube.
- The Super
Vibrex pile has an enlarged base. After being filled with concrete and
reinforcement has been placed, the tube is extracted about 2 meters
(depending on the size of the required pile base). Then the tube is
refilled with concrete, closed at the top and driven again to its original
depth. During redriving, the lower part of the concrete shaft is radially
displaced, thus forming the enlarged base. The diameter of the enlarged
base depends on the amount of concrete, which had been displaced and
on the geotechnical conditions.
- Thereafter,
the vibrator is again clamped to the tube, which is extracted by vibration.
The amount of concrete, necessary for forming the required shaft diameter,
is estimated beforehand. In case of over-consumption of concrete (in
very loose soils), the tube is refilled before being completely extracted.
Advantages:
- Fast method
of pile installation
- Economical,
since reinforce-ment is installed after tube installation, compared
to precast piles, where reinforcement must be designed with respect
to transport and handling.
- Reinforcement
of pile shaft can be increased at top of pile.
- Effective
method of making an enlarged base, if so desired. Due to an increased
end bearing and optimal friction along the shaft, a high bearing capacity
is usually achieved.
- Allowable
pile loads can be very high, up to 2500 kN
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