What are the Types of Building Foundations?
Building foundation types are one of the most important materials used in the construction industry. It is of great importance in terms of the durability and strength of the structure. Therefore, the foundations are quite diverse. In this article, we will examine the types of foundations in detail.
The foundation is a reinforced concrete element placed under the structures and carries the weight of the structure. It is very important for the safety of the building that the structure sits on solid foundations. The height of the foundations is determined according to the characteristics of the land on which the structure is located and the height of the building. Additionally, foundations can be of different types depending on the bearing capacity of the ground.
Foundation types are divided into two groups: shallow (superficial) foundations and deep foundations.
1. Shallow Foundations
Singular (Individual) Foundations
Individual foundations are concrete blocks, usually cube or rectangular, that transmit the load of the structure to the soil ground. This type of foundation is generally used for smaller structures and light load-bearing structures. For example, single foundations may be preferred in structures such as single-storey houses, garages or small buildings. It can also be used as the supporting foundation of high building elements such as poles or columns.
Individual foundations generally do not require deep excavations and are relatively low cost. It is important that they have sufficient carrying capacity to transfer the load of the structure to the soil ground. Therefore, when designing the foundation, factors such as soil bearing capacity, structure load, soil properties and local building regulations should be taken into account.
Another important parameter used in the design of individual foundations is the foundation width. The foundation width must be sufficient to ensure that the building load is evenly distributed on the ground. It is also important that the foundation base is deep enough relative to the groundwater level. Thus, ground water does not affect the durability of the foundation.
Continuous (Strip or Continuous) Foundations
Continuous (strip or continuous) foundations are one of the foundation types used for larger structures or heavy load-bearing structural elements. This type of foundation provides durability to the structure by distributing the building load evenly on the ground. Strip foundations are long, narrow concrete beams that usually run along structure walls or columns.
Continuous foundations increase the bearing capacity of the ground by distributing the total load over a larger area in larger structures. Since this type of foundation is structurally more complex, it is preferred in cases where greater bearing capacity and durability are needed. For example, continuous foundations are used for large structures such as multi-storey buildings, bridges or industrial structures.
Strip foundations are located along structure walls or columns and often extend one meter or more below the foundation area. The foundation width is determined by taking into account the building load and the bearing capacity of the ground, as well as local building regulations. Strip foundations are generally constructed of reinforced concrete and reinforced with steel reinforcement.
Raft Foundations
Raft foundations are a reinforced concrete slab-shaped foundation system and are generally used on grounds with low bearing capacity or on grounds with unequal bearing capacity. This type of foundation provides durability to the structure by distributing the building load on the ground.
Raft foundations are usually constructed as a flat concrete slab and are located under structure walls or columns. The ground beneath the slab must be capable of supporting the structure load. Raft foundations provide wider support to the structure by increasing the bearing capacity of the ground.
The advantages of raft foundations include reducing ground movements, providing more homogeneous durability to the structure, and being able to be used even on grounds with low bearing capacity. Additionally, raft foundations can be a more economical foundation system because it requires less excavation and less material use.
Plaque Basics
Plate foundations are a foundation system used for large structures or heavy load-bearing structural elements. This type of foundation provides durability by distributing the building load to the ground. Plate foundations are constructed as flat, wide concrete slabs and are often reinforced to increase the bearing capacity of the ground.
Plate foundations provide durability to the structure and reduce the effects of ground movements. However, the design and construction of slab foundations should be done by taking into account factors such as building load, soil bearing capacity, local building regulations and soil survey results. Therefore, it is important to work with an experienced structural engineer. Plate foundations are used for large buildings, industrial facilities, bridges and similar structures.
Crate Foundations
Crate foundations are a foundation system generally used to support structures in liquefiable or loose soils. This type of foundation is ground improvement work done to increase the bearing capacity of the ground. Box foundations provide durability to the structure by increasing the bearing capacity on the ground.
Box foundations are generally constructed in the form of wooden or reinforced concrete boxes. Boxes are created by compressing or reinforcing materials placed on the ground. These materials are generally materials that increase the bearing capacity of the ground, such as sand, gravel, stabilized soil or compacted fill materials.
2. Deep Foundations
Foot Foundations
Footing foundations are foundation systems that transfer the bearing loads of buildings to the ground and provide durability to the structure. They are reinforced concrete blocks that are generally rectangular or square in shape and placed on building elements.
Footing foundations are usually placed under structural elements that rest on a single column or pole. This type of foundation provides stability to the structure by transferring the building load to the ground. It is especially used in light structures or floors with low bearing capacity.
The pier foundations are constructed as a reinforced concrete block joined by a column connected to the structural elements. The block sits on the ground and transfers the building load to the ground. Footing foundations are generally suitable for smaller structures and distribute the load on the building elements evenly to the ground.
Pile Foundations
Pile foundations are deep foundation systems that allow structures to sit on a more solid layer of the ground. Piles are long cylindrical or conical shaped poles usually made of concrete or steel and are placed by driving or drilling into the ground.
Pile foundations provide durability to the structure by increasing the bearing capacity of the ground. It is preferred in cases where the ground has insufficient bearing capacity or in areas where the building load is intense. Pile foundations are used for large structures, bridges and other engineering structures.
Piles are usually placed by driving them into a more solid layer of the ground. Piles driven into the ground transfer the building load to the ground while also preventing lateral movement of the piles. When the bearing capacity of the ground is low, piles are placed by drilling, thus providing a deeper connection to the ground.
Caissons
Caissons are a type of pile foundations, a traditionally used foundation system. It is constructed as a network structure consisting of wooden sticks and a concrete plate placed on top of this network.
Caisson foundations are used especially on soft soils or in areas close to water. Wooden bars are used to increase the bearing capacity of the ground placed under the foundation. Wooden bars ensure the stability of the foundation by transferring the load spread on the ground to a larger area.
The construction of caisson foundations begins with excavating and leveling the foundation area. Next, wooden bars are placed under the foundation. These rods are placed at a certain distance and diagonally to create a network structure. Finally, the foundation is completed by pouring the concrete slab.
Foundation Curtains
Foundation walls are the foundation systems of high-rise buildings or bridges and generally have a reinforced concrete structure. This type of foundation provides durability, coping with the horizontal loads of tall buildings or bridges.
Foundation shear walls consist of reinforced concrete shear walls that rise above the foundation structure and provide support to the structure. These shear walls ensure the stability of the foundation by transferring the building loads to the ground and increasing the carrying capacity.
Deep Beam Foundations
Deep beam foundations are reinforced reinforced concrete foundations used to carry heavy loads such as large structures or bridges. This foundation system consists of deep piles supported by beam-shaped reinforced concrete elements.
The advantages of deep beam foundations include their ability to carry large loads, reducing the effects of ground movements and providing stability to the structure. In addition, these foundation systems increase the bearing capacity of the ground and allow the structure to sit safely.
