Deep Foundation

• Prakash S & Sharma HD., 1990, Pile foundation in Engineering practice, John Wiley $ Sons

Bearing pile

Friction pile

Pile under uplift

PPile under lateral loads

Batter piles under lateral load

Situations in which deep foundations may be needed (Vesic, 1977; FHWA, 2006a).

TIMBER PILES i. ii. iii. iv.

v.

Have been used since ancient times Length of timber piles depends on types of trees used to harvest the piles, Common length are 12m It is susceptible to termites, marine organisms and rot within zones exposed to seasonal changes. Eventhough it’s cheaper but it has low capacity and can’t take hard driving.

CAST IN PLACE CONCRETE PILES i.

Formed by driving a cylindrical steel shell into the ground to the desired depth and cavity of shell is filled with fluid concrete.

ii.

The steel shell doesn’t contribute to the load transfer capacity of the pile.

iii.

It’s purpose is to open a hole in a ground and keep it open to facilitate the construction of concrete pile. (same function as formwork)

iv.

Vigilant quality control & good construction practice are necessary to ensure the integrity of cast-in-place piles.

Among the advantages of Cast-In-Place Concrete are :     

Can sustain hard driving Resistant to marine organism Easily inspected Length can be changed easily Easy to handle and ship

PRECAST CONCRETE PILES i. ii. iii.

iv.

Usually have square/circular/octagonal cross sections. Fabricated in a construction yard from reinforced or pre-stressed concrete. Disadvantages of this pile are problems in transporting long piles, cutting and lengthening. It has higher capacity than timber piles.

PRECAST CONCRETE PILES i. ii. iii.

iv.

Usually have square/circular/octagonal cross sections. Fabricated in a construction yard from reinforced or pre-stressed concrete. Disadvantages of this pile are problems in transporting long piles, cutting and lengthening. It has higher capacity than timber piles.

TYPES OF PILE CHOSEN DEPENDS ON FOLLOWING FACTORS: a) b) c) d) e)

What type of pile is readily available Location & type of structure (magnitude of loading) Ground Condition (soil type) Cost Durability

TYPES OF PILE CONSTRUCTION Displacement Piles - It cause the soil to be displaced radially as well as vertically as pile shaft is driven or jacked into the ground. b) Non Displacement Piles - It cause the soil to be removed and the resulting hole filled with concrete or a pre cast concrete pile is dropped into the hole and grouted in. a)

Displacement Pile

Replacement Pile / Non Displacement Pile

Effect of installation of piles Ground disturbance • Large displacement • Small displacement • Non displacement pile

• Composite pile

Effect of installation of piles: Effects of pile driving in clays

Effect of installation of piles: Effects of pile driving in clays

(1962 )

Negative skin friction Pile driven in a soft clay or recently placed fill and has its tip resting in a dense stratum the settlement of both the pile and the soft clay or fill is taking place after the pile has been driven and loaded. During and immediately after driving, a portion of the load is resisted by adhesion of soft soil with pile. But, as consolidation of the soft clay proceeds, it transmits all the load onto the tip of the pile.

Piles in soft soil overlying dense strata: (a) Skin friction immediately and during pile driving, (b) negative skin friction

Friction pile may be used to support downward load

Building movement due to pile driven

Pile heave

1971

There 2 type of end bearing piles that is preformed timber pile & in-sitereinforced concrete pile

Effects of installing bored piles in clays

Effects of installing bored piles in clays

Effects of installing bored piles in sands

Effects of installing bored piles in sands

Pile hammer

Bored pile with casing

Equipment installation Installation by driving

Equipment installation Installation by driving

Equipment installation Installation by driving

Equipment installation Installation by driving

Equipment installation Installation by driving

Equipment installation Installation by driving

Equipment installation Installation by driving

Equipment installation

Installation by drilling (boring)

Equipment installation

Installation by drilling (boring)

Equipment installation

Installation by drilling (boring)

Equipment installation

Installation by drilling (boring)

Equipment installation

Installation by drilling (boring)

Equipment installation

Installation by drilling (boring)

Resume of deep foundations