Building Components and Construction System
Contents
Recall the Basic functional requirements of a Building 2
Recall the following Components of a Building: i. Foundation ii. Plinth, iii. Super-structure 4
Recall the Purpose of Foundation 7
Recall the Depth of Foundation 8
Recall the Bearing capacity of a Soil 10
Recall the Well Foundation/Caisson 12
Recall the following types of Building: i. Group A ii. Group B iii. Group C iv. Group D v. Group E vi. Group F vii. Group G viii. Group H ix. Group I
The classification of buildings into different groups, such as Group A, Group B, etc., is a way to categorise buildings based on their intended use, occupancy, and level of hazard. The classification system may vary by country or region, but in general, the groups are defined as follows:
i. Group A: Buildings that are intended for assembly, such as cinemas, theatres, and auditoriums. These buildings typically have a large number of occupants and are considered to have a high level of hazard.
ii. Group B: Buildings that are intended for business, such as offices and banks. These buildings typically have a moderate number of occupants and are considered to have a moderate level of hazard.
iii. Group C: Buildings that are intended for residential use, such as apartments and houses. These buildings typically have a small number of occupants and are considered to have a low level of hazard.
iv. Group D: Buildings that are intended for care, such as hospitals and nursing homes. These buildings typically have a large number of occupants and are considered to have a high level of hazard.
v. Group E: Buildings that are intended for education, such as schools and universities. These buildings typically have a moderate number of occupants and are considered to have a moderate level of hazard.
vi. Group F: Buildings that are intended for storage, such as warehouses and storage buildings. These buildings typically have a small number of occupants and are considered to have a low level of hazard.
vii. Group G: Buildings that are intended for high hazard use, such as power plants and chemical plants. These buildings typically have a small number of occupants and are considered to have a very high level of hazard.
viii. Group H: Buildings that are intended for hazardous use, such as aircraft hangers and factories that use flammable liquids. These buildings typically have a small number of occupants and are considered to have an extremely high level of hazard.
ix. Group I: Buildings that are intended for low hazard use, such as agricultural buildings and detached garages. These buildings typically have a small number of occupants and are considered to have a very low level of hazard.
It’s worth mentioning that this can differ based on the country or region and some classification systems may have different, more specific or fewer groups and also the intended use, occupancy and level of hazard might not be the only criteria to classify the building but also construction types, height and area.
Recall the Basic functional requirements of a Building
The basic functional requirements of a building are the fundamental needs that a building must fulfil in order to be considered suitable for its intended use. These requirements typically include the following:
- Structural integrity: The building must be able to support its own weight, as well as any additional loads such as wind, snow, and earthquakes.
- Stability: The building must be able to maintain its structural integrity under various environmental conditions.
- Access: The building must provide easy and safe access to all occupants, including those with disabilities.
- Egress: The building must provide adequate means of escape in case of emergency.
- Lighting: The building must provide natural or artificial light for all areas, including hallways, stairwells, and bathrooms.
- Ventilation: The building must provide adequate fresh air for all occupants.
- Climate control: The building must be able to maintain a comfortable temperature and humidity level for all occupants.
- Acoustics: The building must be designed to control noise levels and prevent the transmission of sound between adjacent spaces.
- Fire protection: The building must be designed and constructed to minimise the risk of fire and provide adequate means of egress in case of fire.
- Sanitation: The building must be designed and constructed to provide adequate sanitation facilities and protect occupants from health hazards.
- Energy efficiency: The building should be designed and constructed to minimise energy consumption, by optimising natural lighting, insulation and thermal gain, and providing efficient systems for heating and cooling.
- Durability and maintenance: The building should be designed and constructed to be durable and easy to maintain, using materials and systems that are long-lasting and resistant to wear and tear.
These requirements are not exhaustive and other requirements may be added depending on the building code, use or function of the building, and its location. Additionally, the specific requirements and regulations may vary by country or region.
Recall the following Components of a Building: i. Foundation ii. Plinth, iii. Super-structure
The components of a building are the individual parts that make up the entire structure. Three of the main components of a building are the foundation, plinth, and superstructure.
i. Foundation: The foundation is the part of the building that supports the entire structure and transfers the loads from the building to the ground. It is typically made of concrete and is designed to provide a stable base for the building. It must be able to support the weight of the building, as well as any additional loads such as wind, snow, and earthquakes. There are several types of foundations like shallow foundations (spread footings, strip footings, isolated footings, etc) and deep foundations (pile foundations, pier foundations, etc).
ii. Plinth: The plinth is the base of the building, which is built on top of the foundation. It is typically constructed of concrete or masonry and is designed to provide a level base for the superstructure. The plinth is also used to raise the building above the ground level to protect it from flood or water damage.
iii. Superstructure: The superstructure is the part of the building that is above the plinth. It is typically constructed of steel, wood, concrete, or masonry and is designed to support the loads imposed by the roof, walls, and floors of the building. It includes the main load bearing structure, the floors, walls, and the roof. Superstructure also includes the architectural features, staircases, and elevations of the building.
These three components work together to create the overall structure of a building and ensure its stability, safety, and function. It is important to note that these components and materials used can be varied based on the location, the type of building, and codes and regulations.
Recall the following Structure of a Building: i. Load Bearing structure, ii. Framed structure, iii. Composite structure
The structure of a building refers to the way in which the various components of a building, such as the foundation, walls, and roof, are put together to support and distribute the loads imposed on the building. There are several types of building structures, including load-bearing, framed, and composite structures.
i. Load bearing structure: A load-bearing structure is a type of building structure in which the walls of the building are also the main load-bearing elements. The load-bearing walls are typically constructed of masonry or concrete and are designed to support the weight of the roof and upper floors of the building. This type of structure is also called solid wall structure or mass wall structure. Load-bearing structures are simple and straightforward but have several limitations, they are not suitable for taller buildings, can’t accommodate large open spaces, and have less flexibility in terms of architectural design.
ii. Framed structure: A framed structure is a type of building structure in which the walls of the building are not load-bearing. Instead, the loads are carried by a framing system made of steel, wood, or reinforced concrete. This framing system is designed to support the weight of the roof and upper floors of the building. Framed structures are more adaptable to architectural designs, can be used for taller buildings and can provide more open spaces.
iii. Composite structure: A composite structure is a type of building structure that combines both load-bearing and framed elements. In a composite structure, the load-bearing walls and the framing system work together to support the loads imposed on the building. This type of structure combines the advantages of load-bearing and framed structures, it provides more stability and support while providing more flexibility in architectural design.
It is important to note that the selection of the structure type depends on many factors, like load-bearing capacity of the soil, seismic activity, architectural design, cost and others, and also the codes and regulations may vary by country or region.
Define the term Foundation
A foundation is the lower portion of a building’s structure that sits below the ground level and serves as the base for the entire building. It is the structural element that transmits the loads from the building to the ground, and it is responsible for supporting the entire structure and ensuring its stability.
There are several types of foundations, including shallow foundations and deep foundations.
Shallow foundations: These are foundations that are built at or near the surface of the ground. They are generally used for small or lightweight buildings and include spread footings, strip footings, and isolated footings. Spread footings, also known as pad foundations, are typically used for buildings with loads that are concentrated in a small area. Strip footings, also known as trench footings, are used for buildings with loads that are spread out over a longer distance. Isolated footings are used for buildings with loads that are concentrated in specific areas, such as columns.
Deep foundations: These are foundations that are built at depths below the surface of the ground. They are generally used for large or heavy buildings and include pile foundations, pier foundations, and caissons. Pile foundations are made of wood, concrete, or steel and are driven deep into the ground. Pier foundations are similar to pile foundations, but they are made of concrete or masonry and are built above ground level. Caissons are similar to pier foundations, but they are built by excavating a hole and then filling it with concrete.
The type of foundation that is used for a building will depend on several factors, including the soil conditions, the load-bearing capacity of the soil, the height and weight of the building, and the local building codes and regulations.
It is important to note that the foundation is the most critical part of the building and its proper design and construction are essential to ensure the safety, stability and longevity of the building.
Recall the Purpose of Foundation
The purpose of a foundation is to transfer the loads of a building to the ground, and to provide a stable base for the entire structure. The foundation is the most critical part of a building and its proper design and construction are essential to ensure the safety, stability, and longevity of the building.
The main purposes of foundation are:
- Supporting the structure: The foundation is responsible for supporting the entire weight of the building, including the walls, roof, and upper floors. This includes both dead loads (the weight of the building’s permanent components) and live loads (the weight of the building’s occupants and any movable equipment or furnishings).
- Providing a stable base: The foundation must provide a stable base for the building, which means that it must be able to withstand the forces of nature, such as wind, snow, and earthquakes. The foundation must be able to resist the lateral forces that are exerted on the building and provide stability during earthquakes and high winds.
- Protecting the building from the elements: The foundation must be designed and constructed to protect the building from the elements, such as water and frost. This means that it must be able to prevent water from seeping into the building and causing damage, and it must be able to prevent frost heave, which can cause the soil to expand and damage the building’s structure.
- Providing a level surface: The foundation must provide a level surface for the building, which means that it must be able to provide a stable base that is level and plumb. This is important for ensuring that the building is stable and that the walls and roof are properly aligned.
- Raising the building above the ground level: Some foundations are built to raise the building above the ground level to protect it from flood or water damage. This is essential for buildings located in areas prone to flooding.
- Providing isolation: Some foundations also act as isolators, providing isolation from the effects of temperature, moisture, and ground movement that could affect the structural integrity and durability of the building.
It is important to note that the foundation must meet all the building codes and regulations of the area, as well as to be appropriate for the soil conditions and the loads imposed by the building. A proper foundation design and construction are critical in ensuring the safety and stability of the building over its lifetime.
Recall the Depth of Foundation
The depth of a foundation refers to the distance from the ground surface to the bottom of the foundation. The depth of a foundation is an important aspect of its design and construction, as it affects the stability of the building and its ability to resist the forces of nature.
The depth of a foundation will depend on several factors, including the soil conditions, the load-bearing capacity of the soil, the height and weight of the building, and the local building codes and regulations.
In general, the deeper the foundation, the more stability it will provide for the building. This is because a deeper foundation will be able to reach soil that is more stable and better able to support the weight of the building. However, it’s not always possible to excavate deep foundations, especially in areas with underground utilities or restricted access.
The depth of a foundation is classified into two types: shallow foundations and deep foundations.
Shallow foundations: These are foundations that are built at or near the surface of the ground and have a depth of less than 6 feet (about 2 metres) below the ground level. Shallow foundations are typically used for small or lightweight buildings, and are often used in areas where the soil is stable and able to support the weight of the building.
Deep foundations: These are foundations that are built at depths greater than 6 feet (about 2 metres) below the ground level. Deep foundations are typically used for large or heavy buildings, and are often used in areas where the soil is not stable or is unable to support the weight of the building. Some common types of deep foundations include pile foundations, pier foundations, and caissons.
In any case, the foundation depth should be in compliance with the local building codes and regulations and should also be appropriate for the soil conditions and the loads imposed by the building. Consulting a structural engineer or a geotechnical engineer can help to determine the appropriate depth of the foundation for a building.
Recall the Bearing capacity of a Soil
The bearing capacity of a soil refers to the ability of the soil to support the weight of a building and its foundation without experiencing failure or excessive settlement. The bearing capacity of a soil is an important aspect of foundation design, as it determines the type of foundation that can be used for a building, as well as the depth and size of the foundation.
The bearing capacity of a soil is affected by several factors, including the type and density of the soil, the water content of the soil, the depth of the soil, and the presence of any organic or inorganic materials. The bearing capacity of a soil can be determined through a soil test, which involves measuring the properties of the soil and analysing its ability to support the weight of a building.
There are two types of soil bearing capacity: allowable bearing capacity (ABC) and safe bearing capacity (SBC).
Allowable bearing capacity (ABC): The maximum weight that can be applied on a foundation without causing excessive settlement or failure. This value is determined by the soil type and the building code.
Safe bearing capacity (SBC): The maximum weight that can be applied on a foundation without causing failure. This value is usually less than the allowable bearing capacity and is determined by a soil test.
The bearing capacity of a soil is usually expressed in terms of pounds per square foot or kilopascals per square metre. In general, the higher the bearing capacity of a soil, the more stable it is and the less settlement will occur. However, a higher bearing capacity can also require deeper foundations.
It is important to note that the bearing capacity of a soil can vary from location to location, and the soil type can change within a small area. Therefore, a proper soil test should be carried out in the specific location
Define the following types of Shallow Foundation: i. Footings ii. Raft/Mat Foundation, iii. Grillage Foundation
Shallow foundations are foundations that are not very deep, and are typically used for buildings and structures with lightweight loads. They are typically less expensive and easier to construct than deep foundations, and are suitable for a wide range of soil types.
- Footings: Footings are a type of shallow foundation that are used to distribute the load of a structure over a wide area of soil. They are typically used to support individual columns or walls, and are made of reinforced concrete or masonry. They come in various shapes such as square, rectangular, or circular. They are designed to transfer the load to the soil at a point or along a line, depending on the structure’s design and the soil conditions at the site.
- Raft/Mat Foundation: A raft or mat foundation is a type of shallow foundation that is used to distribute the load of a structure over a wide area of soil. It is typically made of reinforced concrete, and is placed directly on the soil beneath the structure. The raft foundation is commonly used for buildings or structures with heavy loads, and is designed to distribute the load over a large area of soil.
- Grillage foundation: A grillage foundation is a type of shallow foundation that is used to support large and heavy loads, such as those found in bridges, heavy machinery, and other industrial structures. It consists of a grid of steel beams or timber beams that are laid on the soil and supported by concrete or masonry piers. The grillage foundation is designed to distribute the load over a wide area of soil, and can be used in situations where the soil conditions are not suitable for other types of shallow foundations.
To summarise, Footings are shallow foundations for single load points and Raft/mat foundation and Grillage foundations are used for buildings or structures with heavy loads which distribute the load over a large area of soil.
Recall the Well Foundation/Caisson
Recall the Well Foundation/Caisson” is a learning outcome that relates to understanding the concept of well foundations, also known as caissons. Well foundations are a type of deep foundation that is used to transfer the load of a structure down to a suitable bearing stratum, usually through rock or hard soil.
A caisson is a watertight retaining structure that is used to dig a hole in the ground and then fill it with concrete to create a foundation for a structure. Caissons are commonly used for foundations of bridges, tall buildings, and other structures where the soil or rock at the surface is not strong enough to support the structure on its own.
The process of constructing a caisson foundation typically involves the following steps:
- Excavation: A hole is drilled or excavated in the ground to reach a suitable bearing stratum. This is typically done using a caisson rig, which is a large machine that can dig deep into the ground.
- Waterproofing: The sides of the hole are then waterproofed to prevent water from entering the excavation. This is done by applying a waterproof membrane or by installing a watertight bulkhead at the top of the excavation.
- Concreting: Concrete is then poured into the excavation to create the foundation. The concrete is typically poured in layers and allowed to cure before the next layer is added.
- Backfilling: After the concrete has cured, the excavation is backfilled with soil. The backfill is compacted to ensure that it is stable and will not settle or erode over time.
Well foundations are particularly useful in the case of deep excavation where the soil at the surface cannot bear the load, but at a greater depth, the soil is strong enough. They are also useful in the case of a high water table, where the structure is built above the water level, to prevent water from entering the structure.
Well foundations/caissons can also be used in combination with other foundation types, such as shallow or spread foundations, depending on the specific needs of the structure and the site conditions. However, the cost of well foundations are usually high compared to other foundation types, due to the complex excavation process and the materials used.
Overall, the well foundation/caisson is an important type of deep foundation that can be used to support structures built on soil or rock that is not strong enough to support the structure on its own. It is a critical aspect in the design and construction of structures, and engineers must be familiar with this method for foundation design, for the structure to be safe and secure.