Geo Technical Engineering and Foundation Engineering

Foundation Engineering

A foundation is defined as that part of the structure that supports the weight of the structure and transmits the load to underlying soil or rock. Foundation engineering applies the knowledge of soil mechanics, rock mechanics, geology, and structural engineering to the design and construction of foundations for buildings and other structures. The most basic aspect of foundation engineering deals with the selection of the type of foundation, such as using a shallow or deep foundation system. Another important aspect of foundation engineering involves the development of design parameters, such as the bearing capacity of the foundation.

Aims of Foundation Engineering study

To be able to calculate the bearing capacity of shallow and deep foundations

Super Structure:

Part of the structure which is above ground level

Foundation:

It is the lowest part of the structure which supports the structure by distributing its load on the soil and keeping it less than the bearing capacity of soil. Usually factor of safety in foundation is 2.5 - 3.0. Foundation can also be said to as the interface between the super structure and the soil.

Why do we use foundation??

If foundation is not provided the stress on the soil due to the building may exceed the bearing capacity of the soil and will fail. Thus, the foundation keeps the load on the soil in allowable range by distributing it on a vast calculated area.

Who is a foundation Engineer???

The one who has enough knowledge and experience to design the foundation. A foundation engineer must have:

Enough knowledge of scientific principles

Primary duty of a foundation engineer is safety and economy

It comes by taking specialized courses e.g. Geology, Soil Mechanics, Foundation Engineering, Structural Engineering etc.

Experience and courage to take engineering judgments

It comes by working with seniors, attending seminars and workshops etc.

Safety

The foundation must be stable and safe in the first place. Safety of a foundation is ensured:

1. By keeping a factor of safety.
2. By avoiding structural failure of foundation itself.
3. By avoiding the excessive settlements (Total settlement + Differential settlement)

Depth requirement:

• Depth should be such that foundation is below seasonal volumetric changes caused by freezing and thawing.
• Depth of foundation should be up to a point where changes of moisture do not occur frequently and abundantly. Erosion should also be prevented and any loose soil should not be underneath foundation e.g. Peat

Spacing requirement:

When laying a foundation the surrounding (already existing foundations of adjacent buildings) should also be considered and the new foundation should be built at a distance from it so that the previous one is not affected by digging or excavation.

Economy and functionality:

The project of foundation designing must be economical and should fulfill all the requirements, necessities and standards.

Design Soil Parameters

Soil Tests
Scientific Procedures
Engineering Judgment