Reinforcement Cement Concrete (General Engineering) (SSC JE)

As per IS : 456-2000 type of slab –

The primary stresses induced in the dome are –
(i) A compressive force acting along the meridian called the meridional thrust
(ii) A force compressive or tensile in nature acting along a horizontal circle on the dome called hoop stress.

• A spherical dome subjected to concentrated load or UDL at crown, the meridional force is always compressive.
• Meridional thrust is maximum at support and hoop force is maximum at crown.
• Radial bar are provided for meridional thrust while circular rings are provided for circumferential/hoop force.

In pre-stressed concrete the purpose of prestressing lays in exerting pressure on the low tensile strength concrete in that areas, where the concrete normally is exposed to tensile stresses and threated by cracking and failure. Normally, prestressing wire are arranged in the lower part of the beam.

Lateral ties–
• The arrangement of lateral ties should be effective in fulfilling the above requirements.
• They should provide adequate lateral support to each longitudinal bar thereby preventing the outward movement of bar.
• Lateral ties is to prevent premature buckling of bars, improve strength, to provide resistance against shear and torsion.

According to IS 456:2000 clause 26.5.1.3 side face reinforcement -
Where the depth of the web in a beam exceeds 750 mm side face reinforcement shall be provided along the two faces.

The total area of such reinforcement shall be not less than 0.1 percent of the web area and shall be distributed equally on two faces at a spacing not exceeding 300 mm or web thickness whichever is less.

The bunkers are large size shallow bins to store grains coal and cement. In bunkers, the plane of rupture intersects the free surface of the stored material. Generally, steel bunkers are used to store coal at power plants and loco-running sheds. Generally these are square or rectangular shaped.
Maximum bending moment at corner or edge
= pl²/12
Maximum bending moment at center
= pl²/24

Main reinforcement bar dia (d₁) = 10 mm
Spacing of main reinforcement bar (S₁) = 10 cm
Replaced diameter d₂ = 12 mm
Replaced bar spacing (S₂) = ?

Spandrel beam–In steel or concrete structure to spandrel beam is the exterior beam that stretches horizontally from one column to another column these are also known as edge beams. Spandrel beams are provided on each floor which helps distinguish floor levels in high rise buildings.