Foundations Definition what is a foundation The low

Foundations:

Definition (what is a foundation? ): The low artificial built part of a structure, which transmit the lower part of the structure to the ground, is called the foundation. Foundation of a structure is always constructed below the ground level so as to increase the lateral stability of the structure. It includes the portion of the structure below the ground level and is build to provide a firm and level surface for transmitting the load of the structure on a large area of the soil laying underneath. The ground on which the foundation rests is called the foundation.

PURPOSE OF FOUNDATION: All engineering structures are provided with foundations at the base to fulfil the following objectives: • To distribute the load of the structure over a large bearing area. • To load the bearing surface at a uniform rate to prevent settlement. • To prevent movement of the supporting materials. • To secure a level and firm bed for building operations. • To increase the stability of the structure as a whole.

PURPOSE OF FOUNDATION (2): Foundations are normally placed below ground level, because the surrounding ground offers the following: • Stability. • Protection against compression. • Protection against weather conditions like rain and drought. Foundations are divided into two classes. • Natural foundations – the soil below the base of the building after excavations have taken place • Artificial foundations – the structure that is placed between the building and natural foundation.

FOUNDATION LOADS: The natural foundation must be able to carry the following loads: • Dead load – the weight of all fixed parts like walls, floors and roofs. • Live load – the weight of people, furniture and household equipment. • Wind load – the load of wind against the walls and roof.

FOUNDATION LOADS (2): The following conditions have an influence on the choice of the correct foundation: • The load bearing ability of the soil, • The dept in which the load bearing soil can be found, • The level of the water table, • The distance of trees from the planted structure, • The total weight of the building.

FOUNDATION LOADS (3): Foundations can be classified in many ways; however, the most common reference is in their form. There are five foundation types: • Strip (mass concrete) foundations, • Raft or float foundations, • Pad or isolated foundations, • Ground beams with column foundations, • Pile foundations.

Question Time: ?

Questions: 1) What is a foundation? 2) Explain the difference between natural and artificial foundations. 3) Natural foundations can carry three types of loads. Name them. 4) List five types of foundations.

Answers: 1) The low artificial built part of a structure, which transmits the lower part of the structure to the ground, is called the foundation. 2) Natural foundations – the soil below the base of the building after excavations have taken place • Artificial foundations – the structure that is placed between the building and natural foundation. 3) Dead load – the weight of all fixed parts like walls, floors and roofs. • Live load – the weight of people, furniture and household equipment. • Wind load – the load of wind against the walls and roof.

Answers cont: 4) Strip (mass concrete) foundations • Raft or float foundations • Pad or isolated foundations • Ground beams with column foundations • Pile foundations