Dab20702_bab 3 Deep Foundation

7/26/2019 Dab20702_bab 3 Deep Foundation

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FOUNDATION

SYSTEMS

The foundation is the building element which

distributes and transmits

the building load to the earth.


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Building

Load

Soil Bearing Capacity

SettlementSettlement


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Applications

Low

Weight

Soft to

Firm Clay

Large Distr ibuted

Weight

Very Large Con centrated

Weight

Dense Sand

Strong Rock


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All foundations will settle to some

extent

Settlement Magnitude: Usually less that 1

Uniform Settlement: Acceptable if within the 1

Differential Settlement: Unacceptable if differences

exceed the 1


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What are the different loads which

constitute the building load?

Dead LoadLive Load

Wind Loads

Thrusts

Seismic


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DEEP FOUNDATIONS

Transfer building load far below soil surface

1. Drilled Piers/Caisson

Friction End Bearing

Belled

Socketed

2. Piles

Friction

End Bearing


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DEEP FOUNDATIONS

DRILLED PIER/CAISSON


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DRILLED PIER/CAISSONLOAD

DRILLED SHAFT

FILLED WITH

CONCRETE

FRICTION

BETWEEN PILE

AND SOIL

DEEP FOUNDATIONS


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DEEP FOUNDATIONS


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DEEP FOUNDATIONS


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DEEP FOUNDATIONS


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PIER /CAISSONPIER CAPS

DEEP FOUNDATIONS


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BELLED PIER /CAISSON

DEEP FOUNDATIONS


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BELLED PIER /CAISSON

DRILLED SHAFT AND

BELL FILLED WITHCONCRETE

BEARING PRESSURE

UNDER BELL

BELL

LOADDEEP FOUNDATIONS


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Driven Piles

DEEP FOUNDATIONS


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Pile Cap

Piles

Floor Slab Floor Slab

Driven Piles

DEEP FOUNDATIONS


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2 Pile Cluster

3 Pile Cluster

4 Pile Cluster

9 Pile Cluster

Driven Piles - Types of Pile Caps:

DEEP FOUNDATIONS


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Steel PointConcrete

PlugOpen

EndedCompressed

Base

Compressed

Concrete

Pedestal

PileSteel Point

CASED PILES UNCASED PILES

1. Mandrel

Driven

2. Driven from the top of the tube 3. Driven from the bottom of the tube 4. Jetted

1,2,3,4 3 2 2

Fluted

Tapered

1 1 1 2

Types of Piles:

DEEP FOUNDATIONS


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PILES


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MATERIALS

TIMBER

Pressure treated/ submerged

STEEL:

H-piles/ Pipe piles

Corrosion possible

CONCRETE: No corrosion/ economical

Sitecast

Precast

DEEP FOUNDATIONS


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DEEP FOUNDATIONS

Pile Driver


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DEEP FOUNDATIONS

CAISSONS

PILES


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DEEP FOUNDATIONS

CAISSONS Reaches down

through layers of

unsatisfactory soil untilit reaches a

satisfactory bearing

soil strata


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PILES A pile is driven

into the earth

rather than drilled

and poured

TYPES

END BEARING

FRICTION PILE


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PILES

Friction Piles


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PILE LOAD TEST


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PILES CLUSTER


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CUTTING OFF PILES


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FORM WORK FOR PILE CAP


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Reinforcing bar

extends up to tie

into future concrete

column

PILE CAP FORMED


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BASE

ISOLATORS

Layers of steel

and rubber

Lead core

Between twosteel plates

With isolator Without isolator

SEISMIC


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METHOD OF STATIC - PILE DRIVEN

WHERE:

f = unit skin friction,

Asurface = pile surface (skin) area,

q = ultimate bearing capacity of soil at the tip of the pile,

Atip=area of the tip


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PILE DRIVEN IN SAND

Where:K = coefficient of lateral earth pressure (0.6 1.25 dengan nilai yang

terkecil digunakan untuk pasir berkolodak dan nilal tertinggi digunakan

untuk endapan yang lain.

= coefficeint of friction between sand and pile materials (refer

table 10-4)

Where: pv = effective vertical pressure adjacent to piles tip

N*q= bearing capacity factor (see figure 10-2)


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Dc = Critical Depth

Dc = 10 D ( Bagi pasir longgar)

Dc = 20 D ( Bagi pasir tumpat)

Where :D = pile diameter


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Figure 10-5


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PILE DRIVEN IN CLAY

Where : adhesion factor (refer figure 10-10)

c = cohesion

A surface =

A tip =


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Multi Layer of soil


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Figure 10-11


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0.9

284 kN284 kN

142 kN


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Figure 10-12


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Figure 10-13


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PILE DRIVING FORMULAS


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Danish Formula


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EXAMPLE 10-7

Given

1. The design capacity of a 300-mm steel-pipe pile is 445 kN.

2. The pile's modulus of elasticity is 2x105

MPa.3. The pile's length is 12 m.

4. The pile's cross-sectional area is 103.2 cm2

5. The hammer is a Vulcan 140C with a weight of pile hammer ram of

623 kN and manufacturer's hammer energy rating of 50 kN-m.

6. Hammer efficiency is assumed to be 0.80.

Required .

1. What should be the average penetration of the pile from the last few

driving blows?

2. How many blows/ft for the last foot of penetration are required for

the design capacity, using the Danish formula?


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UJIAN BEBAN CERUCUK(LOAD TEST)


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END

Dab20702_bab 3 Deep Foundation

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