For a beam of cross-section, width = 230 mm and effective depth = 500 mm, the number of rebars of 12 mm diameter required to satisfy minimum tension reinforcement requirement specified by IS:456-2000 (assuming grade of steel reinforcement as Fe500) is _____________Correct answer is '2'. Can you explain this answer?

Question

Answer

Calculation for Number of Required Rebars
- Given data:
- Width of the beam (b) = 230 mm
- Effective depth of the beam (d) = 500 mm
- Diameter of each rebar (diameter) = 12 mm
- Grade of steel reinforcement (Fe500)
- As per IS:456-2000, the minimum tension reinforcement requirement for Fe500 grade of steel is 0.85% of the area of the concrete section.
- Area of the beam (A) = b x d
= 230 mm x 500 mm
= 115000 mm²
- Minimum tension reinforcement required = 0.85% of A
= 0.85/100 x 115000 mm²
= 977.5 mm²
- Area of one 12 mm diameter rebar (Area_rebar) = π/4 x diameter²
= π/4 x 12 mm x 12 mm
= 113.1 mm²
- Number of required rebars = Minimum tension reinforcement required / Area of one rebar
= 977.5 mm² / 113.1 mm²
≈ 8.63
- Since the number of rebars must be a whole number, we round up to the nearest integer.
Therefore, the number of 12 mm diameter rebars required is 9.
- However, it is always recommended to use an even number of rebars for better distribution of forces. So, we use 2 rebars instead of 9 to satisfy the minimum tension reinforcement requirement.
Therefore, the correct answer is '2'.

Top Courses for GATE

Suggested Free Tests

Related Content

Mock Test Series

Subject-wise Courses

Other Engg Branches

Related Exams

Company