CHAPTER 9:FOUNDATION

9.1 Interpretation Of Foundation

9.2 The Functions Of Foundation

9.3 Factors That Influencing The Foundation Designing

9.4 The Types Of Foundation

IDENTIFYING ….

Ground Level

Super-structure

Sub-structure

The Foundation

In your opinion, what the purpose of

foundationfor the building?

The importance of foundations in building constructions Buildings are built for a purpose: schools for

education, offices for work, theatres for culture. Each building is a blend of form and function - to be aesthetically pleasing as well as to fulfill the purpose for which it was created.

Foundations do not typically contribute to the architectural aesthetics of a building. Yet, without suitable foundations, a building will not function effectively, will be unsafe and its architectural merits will rapidly fade.

Foundation Definition

“Foundation is the element that provides ultimate supports for the structure and it is static’s and dynamic loads. The foundation include not only that element below ground water level, but also the under line soil and

rock. “

INTRODUCTION The foundation of a building is that part of

walls, piers and columns in direct contact with and transmitting loads to the ground.

Ground Level

Super-structure

Sub-structure

Distribute building load to the ground

The size and depth of a foundation is determined by the structure and size of a building it supports and the nature and bearing capacity of the ground supporting it.

INTRODUCTION Foundation sizes are

determined by the load placed on them.

This load is spread throughout the property and comes to bear on the walls which are actually sitting on the foundation...For example, the weight of the roof, a particularly heavy part of the structure, is spread, via roof trusses to the walls of the structure.

There are two part of foundation :

Column Stump

Footing

THE FUNCTIONS OF FOUNDATION

Transmitting loads to the ground Supports the buildings and provides stability

Factors That Influencing The Foundation Designing

LOAD

DEAD LOAD

LIFE LOAD

WINDLOAD

COST

MATERIAL MACHINE

TECHNOLOGY

MASTERLY SKILFUL WORKER

GROUND CHARACTERISTIC

BEARING CAPACITY

GROUND WATER LEVEL

CHEMICAL CONTAIN

Factors affecting foundation: Soil types and ground water table conditions. Structural requirements and foundations. Construction requirements . Site condition and environmental factor. Economy.

WILL BE

EXPLAIN

IN

CHAPTER

10

Types of foundation The most common types of foundation

systems are classified as shallow and deep :

1) Shallow foundation systems : Are several feet below the bottom of the building.

2) Deep foundations: Extend several dozen feet below the building.

SHALLOW FOUNDATION

PAD FOUNDATIONS

STRIP FOUNDATIONS

RAFT FOUNDATIONS

Pad foundations Pad foundations are used to

support an individual point load such as that due to a structural column. They may be circular, square or rectangular. They usually consist of a block or slab of uniform thickness, but they may be stepped or haunches if they are required to spread the load from a heavy column.

Pad foundations are usually shallow, but deep pad foundations can also be used.

Strip foundations

Strip foundations are used to support a line of loads, either due to a load-bearing wall, or if a line of columns need supporting where column positions are so close that individual pad foundations would be inappropriate.

Raft foundations Raft foundations are used to spread the load from a structure

over a large area, normally the entire area of the structure. They are used when column loads or other structural loads are close together and individual pad foundations would interact.

A raft foundation normally consists of a concrete slab which extends over the entire loaded area. It may be stiffened by ribs or beams incorporated into the foundation.

Raft foundations have the advantage of reducing differential settlements as the concrete slab resists differential movements between loading positions. They are often needed on soft or loose soils with low bearing capacity as they can spread the loads over a larger area.

CHAPTER 10:PILES

10.1 Interpretation Of Piles10.2 The Needs of Piling 10.3 The Concept of Piles Load Distributions10.4 Pile Load Test10.5 Types of Piles

INTRODUCTION Piled foundations can be

classified according to the type of pile - (different structures to be supported, and different ground conditions, require different types of resistance) and the type of construction - (different materials, structures and processes can be used).

Column Stump

Pile Cap

Pile

THE NEEDS OF PILING Piles are often used because adequate bearing

capacity can not be found at shallow enough depths to support the structural loads.

It is important to understand that piles get support from both end bearing and skin friction. The proportion of carrying capacity generated by either end bearing or skin friction depends on the soil conditions.

Piles can be used to support various different types of structural loads.

THE CONCEPT OF PILES LOAD DISTRIBUTIONS

End Bearing Skin Friction

Load

Friction

Hard Imcompressible Layer

Load

End Bearing End bearing piles are those

which terminate in hard, relatively impenetrable material such as rock or very dense sand and gravel. They derive most of their carrying capacity from the resistance of the stratum at the toe of the pile.

Skin Friction Friction piles obtain a greater

part of their carrying capacity by skin friction or adhesion. This tends to occur when piles do not reach an impenetrable stratum but are driven for some distance into a penetrable soil. Their carrying capacity is derived partly from end bearing and partly from skin friction between the embedded surface of the soil and the surrounding soil.

PILE LOAD TEST

DEEP FOUNDATION

PILES

END BEARING

PILES

FRICTION PILES

SETTLEMENTREDUCING

PILES

TENSION PILES

LATERALLYLOADED

PILES

PILES INFILL