TOPIC 3: DESIGN AND ANALYSIS OF SHALLOW FOUNDATION

WEEK 6

• SETTLEMENT OF FOUNDATION ON SOIL

• REVIEW OF VERTICAL STRESS DISTRIBUTION

• FOUNDATION ON FILL

Learning Outcomes

Students should be able to:

• Determine the type of foundation on fill

(CO2-PO10)

SETTLEMENT OF SHALLOW FOUNDATION

Total settlement = Immediate Settlement + Consolidation Settlement

Immediate settlement (elastic) takes place during or immediately after the construction of the structure.

Consolidation Settlement occurs over a period of time. Consists of:

•Primary – squeezing of water from its void•Secondary – slippage and reorientation of soil particles

Calculation of Vertical Stress Increase

A) Stress Increase due to Concentrated Load

B) Stress due to Circularly Loaded Area

C) 2 : 1 Method

OTHER METHODS

• Newmarks Chart

• Fadums Chart

• Pressure Bulbs Chart

FOUNDATION ON FILL

Type of Fill

• Non engineered fill

• Engineered fill

• Reclaimed land

Foundation Selection

• May use raft for engineered fill – need to confirm before construction

• Ground improvement for reclaimed land – PVD, Vibro compaction, Dynamic ompaction, stone column etc

• Piling for non engineered fill.

TOPIC 3: DESIGN AND ANALYSIS OF SHALLOW FOUNDATION

WEEK 7

• Theoretical and Empirical Method for

Estimating Settlement.

• Total and Differential Settlement to Limit Damage

Learning Outcomes

Students should be able to:

• Able to estimate settlement (CO2-PO10)

• Able to determine angular distortion

(CO2-PO10)

• Able to discuss on tolerable settlement.

(CO2-PO10)

Elastic Settlement

Settlement of Rigid Foundation

Empirical Methods

Method based on Standard Penetration Test

Elastic Parameters of Soil

Correlation

Primary Consolidation Settlement

Primary Consolidation Settlement Calculations

Secondary Compression Index

Tolerable Settlement of Buildings

Parameters for Differential Settlement

Tolerable Settlement of Buildings

Guideline for Tolerable Settlement

Limiting Angular Distortion

Field Load Test

Test in Clay, qu(F) = qu(P)

Sand, qu(F) = qu(P) BF/BP

For a given qo

Terzaghi and Peck:

For sand, SF/SP = 4/ (1 +BP/BF)2

Clay, SF = SP. BF/BP

Calculate the average Stress Increase for the clay layer and the Consolidation Settlement