If detailed drawings are not available, the steel reinforcement may be calculated approximately on the percentage basis of
- Aheight of building
- Bbrickwork
- CconcreteCorrect
- Dsize of bending
Solution
Concept
If drawings are not available, steel in RCC work is taken as a percentage of the concrete volume.
Formula
Weight of steel = (% of steel / 100) × Volume of concrete × 7850 kg/m3
Step-by-step solution
1. Steel reinforcement is placed inside concrete. 2. If bar details are not known, take steel as a fixed percentage of the RCC volume. 3. Example: beams about 1 to 2%, slabs about 0.7 to 1%, columns about 0.8 to 4%. 4. So steel is calculated on the percentage basis of concrete.
Explanation
Steel bars are always inside RCC members. Without detailed drawings, we take steel as a percentage of the volume of concrete. Then we convert this volume to weight using the density of steel, 7850 kg/m3.
Why the other options are wrong
A: Building height does not directly give the steel quantity. B: Brickwork has no main reinforcement. D: 'Size of bending' is not a basis for estimating quantity.
Shortcut
Steel lives inside concrete, so steel % is taken on concrete volume.
Common mistake
Taking the steel percentage on total building cost or on brickwork.
Correct answer: C) concrete