Types of pile 11(7) Jacked-down steel tube with closed end
(8) Jacked-down solid concrete cylinder.
Large displacement piles (driven and cast-in-place types)
(1) Steel tube driven and withdrawn after placing concrete
(2) Steel tube driven with closed end, left in place and filled with reinforced concrete
(3) Precast concrete shell filled with concrete
(4) Thin-walled steel shell driven by withdrawable mandrel and then filled with concrete
(5) Rotary displacement auger and screw piles
(6) Expander body.
Small displacement piles
(1) Precast concrete (tubular section driven with open end)
(2) Prestressed concrete (tubular section driven with open end)
(3) Steel H-section
(4) Steel tube section (driven with open end and soil removed as required)
(5) Steel box section (driven with open end and soil removed as required).
Replacement piles
(1) Concrete placed in hole drilled by rotary auger, baling, grabbing, airlift or reverse-
circulation methods (bored and cast-in-place)
(2) Tubes placed in hole drilled as above and filled with concrete as necessary
(3) Precast concrete units placed in drilled hole
(4) Cement mortar or concrete injected into drilled hole
(5) Steel sections placed in drilled hole
(6) Steel tube drilled down.
Composite piles
Numerous types of piles of composite construction may be formed by combining units in
each of the above categories or by adopting combinations of piles in more than one category.
Thus composite piles of a displacement type can be formed by jointing a timber section to
a precast concrete section, or a precast concrete pile can have an H-section jointed to its
lower extremity. Composite piles consisting of more than one type can be formed by driv-
ing a steel or precast concrete unit at the base of a drilled hole or by driving a tube and then
drilling out the soil and extending the drill hole to form a bored and cast-in-place pile.
Selection of pile type
The selection of the appropriate type of pile from any of the above categories depends on
the following three principal factors:
(1) The location and type of structure
(2) The ground conditions
(3) Durability.