Reinforced concrete building elements

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Reinforced concrete (RC) is one of the most widely used materials in modern construction. Plain, unreinforced concrete is unsuitable for many structures as it is relatively weak to withstand the stresses induced by vibrations, wind loading, and so on. To increase its all-over strength, steel rods, wires, mesh, or cables are used in concrete before it is set. This reinforcement, often known as rebar, resists tensile forces. It is used in a wide range of applications such

as; slab, wall, beam, column, foundation, and frame construction There is also the number of non-steel reinforcement that is used to control cracking.

Fiber-reinforced concrete

It is a concrete mixture that contains short discrete fibers that are distributed uniformly throughout the material. Fibers can be made of glass, polypropylene, synthetic and natural materials, as well as steel.

Prestressed reinforced concrete

This allows predetermined engineering stresses which are placed in concrete members to counteract the stresses that occur when the subject is loaded. Generally reinforced concrete, stresses are carried by the steel reinforcement, whereas prestressed concrete supports the load by including stresses throughout the entire structural element.

Reinforced concrete is extremely durable which requires little maintenance. It has good thermal mass and has fire resistance. Rebar is generally made from recycled scrap, and at the demolition stage, the concrete and rebar are capable of being separated so that the steel can be recycled.

Structural Elements of Reinforced Concrete Buildings

Slab

A slab is a structural element, made of concrete, that is used to create flat horizontal surfaces such as floors, roof decks, and ceilings. A slab is generally thick which supports beams, columns, walls, or the ground.

There are several different types of the slab,

• Flat slab This is typically a reinforced slab supported directly by columns or caps, without the use of beams. This type of slab is easy to construct which requires little formwork.
• Conventional slab Here the slab is supposed by beams and columns. The thickness of the slab is smaller but the debt of the beam is large.
• The load is transferred from slab to beam and then beam to the column. This type of slab is provided with reinforcement where the horizontal bar is called main reinforcement and the vertical bar is called distribution bar.

A conventional slab is of two types:

• One way slab
• Two-way slab

• Hollow-core ribbed slab This type of slab has longitudinal cores running through it, which decreases the weight of the slab, as well as the amount of concrete required. It is suitable for office buildings, multi-story car parks, and so on.
• Waffle slab This type of slab contains square grids with deep sides, resembling a waffle shape, often used where large spans are required without the interference of columns.
• Solid slab raft This is a type of shallow foundation, formed by a reinforced concrete slab that covers a wide area, often the entire footprint of a building.
• Composite slab These are most commonly made of concrete because of their mass and stiffness which can be used to reduce the floor's deflections and vibrations, and achieve the necessary fire protection and thermal storage.

Wall

Generally, one of the sides of a room or building joining the ceiling and the floors are known as a wall. It is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. Walls are of various types.

• Buttressing wall- A wall designed and constructed to afford lateral support to another wall perpendicular to it, is called buttressing wall. The support is provided from the base to the top of the wall.
• Cavity - A wall constructed from two skins of masonry, the outer skin of which can be brickwork or blockwork and the inner skin of which is generally of blockwork, separated by a cavity to prevent the penetration of moisture and to allow for the installation of thermal insulation.
• Compartment wall- As the name says, it creates a compartment that helps in forming a barrier to the spread of smoke, heat, and toxic gases.
• Curtain wall A non-structural cladding system for the external walls of buildings is known as a curtain wall.

Beam

Long horizontal or inclined members with limited width and height are called beams. Their main function is to transfer loads from the slab to the columns. They typically transfer loads imposed along their length to their endpoints where the loads are transferred to walls, columns, foundations, and so on. Beams are simply supporters, that is, they are supported at both ends but are free to rotate. They are also fixed at both ends and are resistant to rotation. A wide variety of cross-section shapes are commonly available, including; square, rectangular, circular, I-shaped, T-shaped, H-shaped, C-shaped, tubular, and so on.

Column

The vertical members that support loads from the beam or slabs are known as columns. They may be subjected to axial loads or moments. For example, a column might transfer loads from a ceiling, floor, or roof slab or from a beam, to a floor or foundations. Columns

are typically constructed from materials such as stone, brick, block, concrete, timber, steel, and so
on, which has good compressive strength.

Foundation

The lower portion of the building structure that transfers its gravity loads to the earth is called the foundation.

There is a very wide range of foundation types suitable for different applications, depending on considerations such as:

• The nature of the load requiring support.
• Ground conditions.
• The presence of water.
• Space availability.
• Accessibility.
• Sensitivity to noise and vibration.

Foundations are generally broken into two categories:

• Shallow foundation- It is used where the loads imposed by a structure are low relative to the bearing capacity of the surface soils.
  
• Deep foundation- They are necessary where the bearing capacity of the surface
soils are not adequate to sup

Framework

Frames are structural members that consist of a combination of slabs, beams, and columns. It refers to a rigid structure that supports a building or other built assets such as a bridge or tunnel, or parts of them.

The word'framework'refers to a structure that underpins or supports a system or concept. In the construction industry the word 'framework' has a number of more specific meanings:

A framework contract allows a client to invite tenders from suppliers of goods and services to be carried out over a period of time on a call-off basis as and when required. The structural frame of a building or other built asset such as a bridge, tunnel, and so on.