Literature review is a collection of different studies and published information which can help in simplify and make the topic clear in brief. This chapter focuses in the theory part more than the practical and calculations, this can help in preparing the required assumptions and choosing the suitable specifications for the selected cases of the project. Anyway, it gives an overview of particular topics that related to the aim and objectives of designing some of main elements by different codes of practice (ACI, BS and IS). Understanding the content is the most necessary part currently because it assists to have good background and thinking critically which make the decisions easier and support the government to have national code.
Classification of Buildings Based on its Uses
A building is a structure which is made by human beings. It is containing of different types of elements such as slab, beam, column and foundation. Each type of building is made based on its function. Moreover, the building can be only as a ground level or it can be multi-storey (two stories up to more than 100 stories). There are many types of buildings based on their uses and the following are some examples of it:
This type of structure is made to use for living purpose. The main facilities of these type of buildings are kitchen, bath rooms, and bed rooms. Single-Family home, condominium, hostel and townhouses are some examples of residential buildings.
These kind of buildings are built for business purposes such as transaction of business for the public, the keeping of accounts and records and some other similar purposes. Banks, professional establishments, etc. are some examples of this type of building.
The usage of this type of building is to deal with both light and heavy materials and work on them with some operations. In this type of buildings there is a risk of some chemical materials which needs to protect and deal with it in a safe way. Furthermore, dealing with the machines causes vibration which should take into consideration. Factory, power plant and foundry are some examples of industrial buildings.
To get knowledge and learn in this life people need a good environment. This environment can be a building which considers many facilities such as cafeteria, library, offices, class rooms, student center, etc.
The main purpose of this building is providing services to the public and many of these services are provided for free. Libraries, post offices and courthouses are some examples of public buildings.
Substructure and superstructure are the basic parts of the building and each have several components that come in a different sizes, shapes and functions as following below. Substructure is the part which constructed below the ground and include foundation that is distribute the loads safely into the soil. On the other hand, superstructure is the part above the ground level which contains various elements such as slabs, beams and columns that are provided to transfer the loads below to the foundation.
Slab is one of the most efficient members in the structure which is constructed to transfer live load, dead load and many other forces as wind load to the beams. Moreover, it is used as a floor, roof, staircase and foundation. It can be supported by columns, walls or beams.
In general, the slab is classified into varies types and the choice of the suitable type for a particular structure largely depending on length of the span, loading conditions and economy.
Types of slab based on the presence of elements
This kind of slab supported with both beams and columns. It has small thickness while the depth of beam is large thus the load transferred to the beams then to the columns. Specifically, it is used in floors of multi storied building.
It is a slab which constructed with the number of holes that gives an appearance of waffles as illustrates in figure 2-8. Generally, it is used where larger slab is required to avoid many columns interposing the space. Comparatively it has special features which are economical, lightweight and fast in construction.
Flat slab is a member which directly constructed in columns without using beams as illustrated in figure 2-9, thus the loads transferred from the slab to the columns directly and sometimes caps are provided. It has a special advantage that is absent on the other types which is reduced the height of the building so, the cost will decrease. Generally, it is used where beams are not required such as parking decks and commercial building.
Types of slab based on the size
It is the slab which bend in one direction along the shorter span as shown in figure 2-6. However, it is supported by beams on two opposite sides and the main reinforcement is provided in the shorter span. In one-way slab the ratio of the longer span to the shorter span is greater than two (ly/lx>2).
This type is bend in two directions along x-axis and y-axis as shown in figure 2-7. Furthermore, it is supported on all four sides by beam and the main reinforcement is provided in both directions. It is considered as two-way slab when the ratio of the longer span to the shorter span less than or equals two (ly/lx?2).
Horizontal structural member which construct to carry vertical loads which caused by the floors and the roof. It can be made from different materials such as steel, wood and aluminum. In addition, the beam varies in size, shape and type of support.
Types of beams according to the supports condition
Simply supported beam:
The beam which has support at both ends, one of them pinned and the other is roller thus both ends free to rotate and it hasn’t moment resistance.
This type is same as simply supported beam, but it has more than two supports and it has more than one span as figure 2-11 shows.
The beam which can have two supports at different points, and one of the ends or both should be free.
This type of beam is fixed from one side and other side is free. Mostly used for creating balconies and trusses on bridges.
This type of beams has a fixed end in both sides. The fixed ends mean that the slopes at the end will remain zero.
Types of beams according to the equilibrium condition:
Statically determinate beam: The static equilibrium equations ?H=0, ?V=0, ?M=0 are adequate for finding the internal reaction and forces of the structure.
Statically indeterminate beam: The static equilibrium equations are not enough for analysing the beam.
The compression structural member which used to support the various elements above it and transfer their loads down to the foundation. In addition, it is useful to resist bending moments coming by beams. Generally, column is usually built by using materials have high compressive strength such as block, brick and concrete. According to the shape of cross section it is classified as square, rectangular, circular and T-shape etc. Also, column is categorized into two following types according to the slenderness ratio (L/R):
The ratio of effective length to least lateral dimension is lesser than 12. It has more bearing capacity and it is subjected to compressive stress thus fails by crushing.
The ratio of effective length to least lateral dimension is more than 12. Generally, as the length of column increases the load bearing capacity decreases, and it is fails by buckling.
The lowest portion in the building which is necessary to take the whole loads coming from the structure and distribute it safely into the soil. Type of foundation is chosen according to the type of building, design style and soil bearing capacity. Mostly, it is classified based on the ratio of depth to width of the foundation as the following:
One of the major types of foundations that transfers the loads of the building immediately below to the soil layers very close to the surface. It can be considered as shallow foundation when the depth is equal or less than the width (D ? B) as shown in figure 2-17. However, shallow foundation is classified into different types:
It is also known as a single footing because it is provided to support individual columns. This type of footing can be found in three cases which are steady thickness, stepped or has a sloped top. Usually, it is used were the columns spaced at long distances.
The shape of this footing can be rectangular or trapezoidal according to the loads of the columns. Commonly, it is used were two columns closed to each other or were one column existence at or near the property line.
Two single footings are connected with a concrete beam which is called strap beam. It is often used to spread the weight of footing which support eccentric column to adjoining footing.
A load bearing wall or number of columns have close spaces, both can be supported by strip footing which can be define as continues foundation with small depth compared to its length.
Raft or mat foundation:
Often this type is selected to support different structural elements. Moreover, it is used were the load bearing capacity of the soil is low and the loads is heavy, so the loads are distributed into large area of soil.
It is the type of foundation that required to transfer building loads to the deep soil strata, unlike shallow foundation. There are many reasons that why engineers recommend for using this type of foundation, some of the reasons are very large design loads and poor soil at shallow depth. However, it can be considered as deep foundation when the depth is greater than the width of the foundation (D ? B), It has two major types which are pile and pier foundation as shown below.
When the layer of soil close to the earth surface is poor in strength and the soil at deep layer has adequate bearing capacity, number of piles are used to transfer the loads to the deep strata by end bearing or friction.
It is an immobile element which can support heavy loads that coming from the structural elements. Mostly, it is used in bridges and very tall multi stories buildings.