Types of Foundation in Construction

The foundation is the most important part of any structure because if we make a small mistake in foundation design it will reflect huge impact.

Function of Foundation

The foundation has received the all loads like dead load, live load, seismic load, etc., which is distributed to column & it transfer to the ground. The entire pressure of the structure should not greater than the safe bearing capacity of soil (SBC).

Types of foundation

We have to consider the following factor while designing the foundation

  1. Bearing capacity of the soil
  2. Different types of load
  3. Depth of foundation
  4. Available Area

The foundation has classified two major types Shallow Foundation & Deep Foundation.

Shallow Foundation

The types of shallow foundation classified as below

                1. Isolated footing               2. Combined footing                           3. Strip footing

When a depth of foundation is less than or equal to the breadth of the foundation is called Shallow foundation. The shallow foundation has classified into three main categories.

Isolated Footing

Isolate – Alone

If each column has an individual footing is called Isolated footing. Most of the small size building has constructed by this type of foundation because it is simple & economical.

types of shallow foundation

Generally, the isolated footing is placed when the soil has the low safe bearing capacity. The common shape of the footings is square, rectangular & circular section.

Combined Footing

There is no big difference between the isolated & combined footing. When more than one columns are placed at a distance below 2 m then it was designed as a combined footing. The combined footings are having a shape Rectangle or trapezoidal.

Types of foundation, shallow foundation

Strip footing

The Strip footing have slight differ compares to other types of shallow foundation. This footing has placed where the soil having good bearing capacity available at below 3m from the ground level.

Another name of Strip footing is Wall footing because the width of the footing is 3 times greater than the depth of footing.

There are two types of Strip footing mentioned below

                                1. Simple Footing                              2.Stepped Footing

Simple Footing

If the structure shall carry a small amount of load then the footing was designed as simple footing.

types of foundation in civil engineering

Stepped Footing

Mostly stepped footing is designed when the ground is slope unless if we provide for the normal ground level it becomes uneconomical.

Types of foundation in civil engineering

Raft/Mat Foundation

Raft & Mat foundations both are same. When the soil bearing capacity is low but the same time the large structure has planned to construct in that area then we have to recommend the Raft foundation (Depth above 3m).

If the selected construction area is very large & type of soil is different from one place to another place. So we excavate the entire area fully & placing Raft foundation.

You Shall ask why we are not using Pile foundation instead of Raft foundation!. because economically it was too high.

Raft foundation, types of deep foundation

In mat foundation, the column has placed at a minimal distance to distribute the load to ground.

Once again remind you, as above said based on the soil bearing capacity the design will differ. If the bearing capacity is good & the structure was small size then we recommend isolated footing.

We must interpret about the one more type of footing that is Strap footing.

Strap Footing

Mostly these type of footing has placed when the construction area is not having much space to give proper foundation. So that in this condition, the Strap footing was provided & the column shall be designed as an eccentrically loaded column.

Types of foundation

Deep Foundation

When the depth of foundation is greater than its width, it is called Deep Foundation. When the depth is greater than 6m then design recommends the deep foundation. Mostly pile foundations are called deep foundation.

Pile Foundation

The main purpose why we use the pile foundation! When the soil has the low bearing capacity or water logged area (Loose soil). Mostly pile foundation have designed when the soil has a low bearing capacity, highly water log area at the same time the foundation to accommodate the large load.

Types of Depp Pile of Foundation.

  1. Bearing piles           2. Friction pile  

End Bearing Pile

End bearing pile shall use when the hard soil (Rock) strata found at a reasonable depth not less than 40m. The End bearing pile simply acts like Column, the entire load of the structure has distributed to the hard surface area. Piles are driven into the soft soil & it will stop when it reaches the hard surface area.

Friction Pile

There is no major difference between the bearing & Friction pile. Friction pile has used at the depth greater than 40m. The same methodology has used to execute the pile work but the friction pile has transfer the entire load of the structure to soil through by Friction between the Surrounded Soil & pile. The load was transferred downward & laterally to the soil.

types of deep foundation

We just see a glance of pile foundation. In the upcoming post, we shall discuss briefly pile foundation.

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