Footing and foundation are some of the most basic terms in the world of civil engineering. If you don’t happen to be part of this vast world, you may not understand the difference between the two.
The Difference Between Footing and Foundation
Simply put, all footings are foundations but not all foundations can be footings. Are you still confused about the details? Let’s break it down.
First and foremost, a structure or building consists of two main portions, the superstructure, and the substructure. The substructure is generally known as the foundation, as it transmits the load of the superstructure. Either columns or a wall is used to transmit the load of the superstructure to the foundation or substructure. The purpose of the foundation is to distribute the load to the soil with the right amount of pressure.
The foundation is the lowest part of any structure. Its key function is to transfer the load of the higher components to the soil. It plays an essential role in any structure. There are usually two types of foundations (shallow foundations and deep foundations). A shallow foundation transfers the load of up to 1.5 meters and deep foundations transfer loads below the ground surface with more than 1.5 meters in depth. Shallow foundations are typically created for low-height structures or structures with a greater horizontal spread compared to their vertical height. It will also be required for a skyscraper that’s sitting on weak soil. It will need a deeper foundation only if there are concrete plans to extend this building vertically down the line.
Pile, Well, and Pier Foundations
Pile, well, and pier foundations make up the umbrella of deep foundations. A pile foundation is used when the topsoil is relatively weak. This is the most common type of deep foundation used for buildings. It’s used where a group of piles transfers the load to the soil. A well foundation is usually used when constructing a bridge where the soil is soft and/or moist. You’ll typically find them in water. A pier foundation consists of a large cylindrical column. The two types of pier foundation include masonry or concrete pier and drilled cassion. Its purpose is to transfer large loads to firm the strata below. A pier is dug out and cast in place.
What exactly is footing?
The footing is the part of the foundation that transfers the load to a larger soil area. It’s the part of the foundation that is in actual contact with the soil. It makes the foundation safe for whatever settlement it’s on. The materials used for footing usually consist of slabs or rebars. Footings are constructed with brickwork, masonry, or concrete.
Footings are typically used with shallow foundations. But unlike just deep and shallow foundations, there are many different types of footings. These include isolated, combined, continuous, strap, strip, raft, pile, and spread footings. To give some examples, strip footing is used for load-bearing walls or rows of columns that are close together. Combined footing is when two or more columns are being supported. They are either rectangular or trapezoidal in shape. Strap footing is when a strap beam is used for two columns. Its purpose is so the footing does not extend to any adjoining property. The width and depth of the footing will depend on the size, the soil, and the type of foundation.
Comparing the two
If these terms still feel a bit confusing, let’s go over their differences in a brief and simplified manner. The footing is what’s actually in contact with the ground, while the foundation is the structure that transfers the load to the earth. A simple way to visualize the difference when comparing it to the human body would be to view the footing as the actual feet of the legs and the foundation being the legs themselves. The foundation can be both shallow or deep, but the footing is typically only used in shallow instances. The footing will transmit the load directly to the soil and the foundation passes it to the ground.
In short, all footings are foundations but not all foundations are footings. This statement alone may put an end to the confusion.
TR Concrete Construction in Omaha, NE
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