Page 11 - Unit2.docx

+ The piles are easy to handle

+ Relatively inexpensive where timber is plentiful.

+ Sections can be joined together and excess length easily removed.

-- The piles will rot above the ground water level. Have a limited bearing capacity.
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-- Can easily be damaged during driving by stones and boulders.

-- The piles are difficult to splice and are attacked by marine borers in salt water.

Prefabricated concrete piles (reinforced) and pre stressed concrete piles.
(driven) affected by the ground water conditions.

+ Do not corrode or rot.

+ Are easy to splice. Relatively inexpensive.

+ The quality of the concrete can be checked before driving.

+ Stable in squeezing ground, for example, soft clays, silts and peats pile
material can be inspected before piling.

+ Can be re driven if affected by ground heave. Construction
procedure unaffected by ground water.

+ Can be driven in long lengths. Can be carried above ground level, for example,
through water for marine structures.

+ Can increase the relative density of a granular founding stratum.

-- Relatively difficult to cut.

-- Displacement, heave, and disturbance of the soil during driving.

-- Can be damaged during driving. Replacement piles may be required.

-- Sometimes problems with noise and vibration.

-- Cannot be driven with very large diameters or in condition of limited headroom.

Driven and cast-in-place concrete piles

Permanently cased (casing left in the ground)

Temporarily cased or uncased (casing retrieved)

+ Can be inspected before casting can easily be cut or extended to the
desired length.