Types of Foundations in Building Construction
/When constructing a new building, the type of foundation used to support the building will depend on a number of factors. The following article outlines some various foundation types and why they are used.
Shallow Foundations
Also referred to as open or spread footings, these foundations are made by first excavating all of the dirt around the footing until you get to the bottom and then building up the footing. This type of footing takes the weight load from each column and spreads it over an extended area so that the weight it’s bearing does not exceed the safe bearing capacity of the soil.
There are three different types of shallow footings commonly used: individual, strip and raft footings.
Individual Footings - These are probably the most commonly used type in building construction, and are used when columns are carrying the weight load of the building. Each column will have its own square (or rectangular) base that it sits on. The number of columns will be determined by the total weight of the building, and the engineer will calculate how much is safe for each to bear.
Strip Footings - This kind of foundation is usually found in older buildings made of masonry where the weight load of the building is carried by whole walls rather than single columns. These footings are long strips that support the weight of entire walls.
Raft Footings - This kind of foundation is commonly used when the building needs an accessible basement. The slab of concrete will act as the foundation in the basement and then the weight of the building is spread out evenly over the entire size of the slab. If the soil is weak in the area, sometimes columns will be placed to help support the load.
Deep Foundations
If the building needs more support, like high-rise apartment buildings, the building construction has to be deeper into the ground. Deep foundations are also known as pile foundations. A pile is a long cylinder made of concrete that is pushed into the ground so that it can support the weight of buildings on top of it. There are two types of deep footings for foundations: end bearing piles and friction piles.
End Bearing Piles - With this type of footing, the end of the pile will be placed on top of an area of soil that is determined to be especially strong. The load of the building will be passed on to the strong layer of soil, or rock, and it acts almost like a footing on its own. This ensures the weight load of the building can safely be passed on to a foundation that will support it.
Friction Piles - This kind of foundation works a little differently. The pile works by transferring the weight load of the building across the full length of the pile using friction. This kind of pile works because it pushes the weight of the building into the soil around it – almost like pushing a solid rod into a tub of thick mud: eventually, as you push it down further, the rod will be able to support weight on top of it. The amount of weight it can support will be proportional to how long the pile is.
For more information, contact Foundation Fix today. We provide Foundation Services to the Beamsville, St. Catharines and Niagara region of Ontario.
