In building construction, a foundation is the lower portion of a building structure that transfers loads from the superstructure to the ground, ensuring the building’s stability and safety.
It is a critical component of building construction because it prevents settlement, cracking, and structural damage.
Consult structural engineers and building experts when choosing an appropriate foundation for your building construction. They will guarantee the stability and safety of the building by evaluating specific site conditions like soil type, groundwater levels, and environmental factors. They will identify the most suitable foundation type and ensure its correct construction using high-quality materials and workmanship, ensuring its integrity and longevity. That’s what Dutum Construction Company offers you.
At Dutum Construction Company Limited, we offer design and construction services for various projects, including building construction, civil engineering, real estate, facility management, integrated infrastructure, and housing development.
Dutum’s services encompass different aspects of building construction, including: designing foundations for buildings and structures; excavation and site preparation; laying foundation slabs and footings; and constructing basements and underground structures.
In this article, we will explore the different types of foundations, their advantages and disadvantages, and factors that affect the selection of foundations in building construction.
Types of foundations
We can broadly classify foundations into three categories: shallow foundations, deep foundations, and special foundations.
1. Shallow Foundations:
Another name for a shallow foundation is a spread footing. It is a type of building foundation that distributes the structural load to the earth near the surface, unlike deep foundations, which transfer the load to a deeper layer.
Typically, lightweight structures use shallow foundations to transfer loads to the soil at a shallow depth.
Typically, a foundation is considered shallow when its width is greater than its depth.
Shallow foundations are less complex and more cost-effective compared to deep foundations, making them the most common choice for smaller-scale structures with lighter loads.
Common types include:
- Strap Footings:
A strap footing serves a similar purpose to combined footings by linking individual columns together with a strap beam. This design is used when column spacing is limited or when columns are located near property lines, allowing for load distribution and structural stability. The strap beam connects the columns, creating a unified foundation system that effectively transmits loads to the ground.
- Combined Footings:
When multiple columns share a foundation and are too closely spaced to allow for individual footings due to overlap, we use combined footings.
Additionally, when property lines or other constraints would cause the eccentric loading of isolated footings, we prefer combined footings. The shape of the combined footing depends on the load distribution among the columns: rectangular for equal loads and trapezoidal for unequal loads. This design ensures a stable and balanced transfer of weight to the ground.
- Mat Foundations:
A mat foundation is a thick slab that covers the entire area of the structure, distributing the load evenly.
This type of foundation, also known as a raft foundation, is a single, continuous slab that covers the entire base of a building, providing uniform support and distributing the structural loads evenly to the ground.
Mat foundations are particularly useful when soil conditions are poor, making other types of footings impractical.
By spreading the load across a large area, mat foundations are ideal for situations where individual footings are not feasible due to soil with low bearing capacity, ensuring a stable and even distribution of weight.
- Isolated Footings:
This type of footing, also known as single-column footing, is an individual slab, typically square, rectangular, or circular in shape, that provides support for each structural member separately. Each column has its own footing, which helps to distribute the weight of the structure to the soil below. Occasionally, designers may design the footing with a sloping or stepped base to accommodate heavier loads.
This type of footing is suitable for structures with relatively low loads, widely spaced columns, and soil that can support the weight at a shallow depth.
- Wall Footing:
This type of footing, also known as strip footing, is a continuous, unbroken strip that provides support for both structural and non-structural load-bearing walls. Located directly beneath the wall, its width typically ranges from two to three times the width of the wall it supports, providing a solid foundation for the structure.
The benefits of a shallow foundation
- Lower cost: Shallow foundations are generally less expensive to construct compared to deep foundations, as they require less material, labor, and specialized equipment.
- Ease of construction: Shallow foundations are typically easier and faster to build, as they do not involve extensive drilling or excavation processes.
- Simpler inspection and maintenance: Throughout the life of the structure, shallow foundations are easier to inspect and maintain because they are closer to the ground surface.
A shallow foundation has disadvantages.
- Limited load capacity: shallow foundations cannot withstand as much load as deep foundations, making them less suitable for large or heavy structures.
- Shallow foundations are more susceptible to settlement issues, particularly in weak or compressible soil conditions, which can lead to structural damage over time.
- Shallow foundations are more sensitive to ground movements, such as frost heaving or expansive soils, which can result in foundation damage or failure.
2. Deep Foundations:
Heavy structures use deep foundations to transfer loads to a deeper soil layer or rock.
Different forms of deep foundations exist, such as piles, piers, drilled shafts, and caissons, all designed to transfer heavy loads to deeper, more stable soil or rock layers.
A structural engineer may opt for a deep foundation over a shallow one in various situations, such as constructing a skyscraper.
Common reasons for this include extremely high load requirements, poor soil quality at shallow depths, and site limitations like proximity to property lines.
Typical types of deep foundations utilized in building construction are:
- Piles Foundations:
Piles are long, slender columns made of concrete, steel, or timber that transfer loads to a deeper soil layer or rock.
Pile foundations are a type of deep foundation that uses vertical columns or piles, installed by driving, drilling, or casting into the ground, to transfer the weight of a structure to more stable and deeper soil layers or bedrock.
As a crucial element in deep foundations, pile foundations offer adaptability to various soil types and ensure structural stability in diverse environmental conditions, providing a reliable and secure foundation for buildings and infrastructure projects.
- Caissons Foundations:
Caissons are large, watertight chambers made of concrete or steel that are sunk into the ground to form a foundation.
Caisson foundations are specialized structural elements designed to support large-scale constructions like piers and bridges. Typically cylindrical in shape, these foundations submerge underwater during construction to provide stability and support in challenging environments, such as waterways or unstable soil conditions, ensuring a solid base for the structure.
- Basement Foundation:
Buildings with one or more floors below ground level, such as houses with basement levels, typically use a basement foundation. Unlike other foundations, which are typically partially hidden, basement foundations are fully exposed and allow for the creation of a “finished” basement space that can be used as a regular room or multipurpose area, providing additional living space beneath the main building.
- Buoyancy Raft Foundation:
Buoyancy Raft foundations, also called compensated foundations, use the buoyancy principle in their design to reduce settlements.
The construction of a hollow foundation structure at a specific depth equalizes or slightly reduces the weight of the removed soil compared to the combined weight of the substructure and superstructure, thereby minimizing the net weight on the soil and subsequent settlements in the shaft.
This innovative design effectively “floats” the foundation, mitigating settlement issues and ensuring a stable base for the structure.
- Drilled shaft foundations:
Drilled shaft foundations, also known as foundations or drilled piers, are a widely used and versatile building component on a global scale. The basic construction process involves drilling a cylindrical hole, placing a reinforcement cage, and then filling the hole with concrete. With drilling equipment and supporting arrangements available on site, it is possible to construct shaft foundations with diameters of up to 6.0 meters and depths exceeding 76.0 meters, making them a reliable and robust foundation solution for various structures.
Advantages of a Deep Foundation
- Greater load capacity: Deep foundations can withstand higher loads compared to shallow foundations, making them suitable for large and heavy structures.
- Deep foundations are suitable for weak surface soils: When the surface soil is weak or compressible, they can transfer the load to stronger soil layers at greater depths.
- Reducing Settlement Issues: In areas with expansive or compressible soils, deep foundations help alleviate these issues by reaching stable soil layers or bedrock, ultimately decreasing the likelihood of differential settlement and associated structural damage.
- Enhanced Seismic Performance: Structures with deep foundations, particularly those anchored into bedrock, exhibit greater seismic resilience. The deeper support helps lessen the impact of ground shake, providing a more stable foundation.
Disadvantages of a deep foundation
- Higher cost: Deep foundations often involve more complex construction processes, resulting in higher material and labor costs compared to shallow foundations.
- Specialized equipment: The installation of deep foundations typically requires specialized equipment, such as drilling rigs and pile drivers, which can add to project costs and logistical challenges.
Factors Affecting Foundation Selection
Several factors influence the selection of a foundation type, including
- Soil Conditions: Soil type, density, and bearing capacity.
- Building Load and Weight: The structure’s weight and load determine the required foundation depth and type.
- Water Table and Drainage: High water tables or poor drainage may require specialized foundations.
- Site Constraints and Accessibility: Limited space or difficult access may influence foundation selection.
Hire the best house construction service.
At Dutum Construction Company Limited, we pride ourselves on being among the top construction companies in Nigeria.
With a team of experts driven by a passion for excellence, Dutum Construction has earned a reputation as the gold standard in Nigeria’s construction industry, consistently showcase unmatched expertise, professionalism, and client satisfaction, making them the go-to construction partner for discerning clients.
For more information about us,
You can visit our website at https://dutumgroup.com.
Or you can email us at info@dutumgroup.com.
Contact information:
We are located in various parts of Nigeria.
Abuja:
10 Danube Close,
off Danube Crescent
Maitama, Abuja
Phone: +234 805 831 7200
Lagos:
2 Abisogun Road,
Off Palace Road,
Oniru Estate,
Maroko, Lagos
Phone: +234 805 831 7200
Ibadan:
Isaac’s Place,
Opp. TOTAL Petrol Station,
Onireke, G.R.A
Dugbe, Ibadan
Phone: +234 706 967 1901
In conclusion, foundations play an important role in building construction, and selecting the appropriate type depends on a variety of factors. An understanding of the different types of foundations and the factors affecting their selection is essential for ensuring the stability and safety of buildings.
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