Arrangement of reinforcement in different structural members
RCC is employed as a structural component. RCC is employed for the following common structural components in a building :-
- Footings
- Columns
- Beams and lintels
- Roofs and slabs
Footings
In rectangular footing, the reinforcement correspondent to the long direction should be dispersed equally across the width of the footing. In short direction, as the support given to the footing by the column is concentrated closely the middle, the moment per unit length is highest i.e. the curvature of the footing is acute readily under the column and reduces in the long direction with greater distance from the column. Due to this, bigger steel area is required in the central section.
Also read : Precast Concrete Construction Details
Columns
- The prime reinforcement in columns is in longitudinal direction, parallel to the direction of the load and comprises of bars provided in square, rectangular or spherical shape.
- Main steel is arranged to combat the compression load together with the concrete.
- The bar should not be under 12 mm in diameter.
- Minimal maximum size of coarse aggregate should be 5 mm.
- The numbers of bars provided in columns should differ from 10, 12, 14, 16 with different diameter.
Beams
Normally, a beam comprises of the following types of reinforcements :-
- Longitudinal Reinforcement.
- Shear Reinforcements.
- Side face reinforcement in the web of the beam is arranged if the depth of the web in a beam surpasses 750 mm.
- Placements of bars in a beam should adhere to the requirements of clause provided in 8.1 and 8.2 of SP34. The standard bar sizes are 6, 8, 10, 12, 16, 20, 25, 32, 50 mm.
- Thickness of the slab is settled depending on the span to depth ratio. Minimum reinforcement is 0.12% for HYSD bars and 0.15% for mild steel bars. The diameters of the bar normally found in slabs are 6 mm, 8 mm, 10 mm, 12 mm and 16 mm.
- The maximum diameter of bar utilized in slab should not go beyond 1/8 of the total thickness of slab. Maximum spanning of main bar is limited to 3 times effective length. For distribution bars, the maximum spacing should be 5 times the effective depth.
