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Consider two RCC beams, P and Q, each having the section 400 mm × 750 mm (effective depth, d = 750 mm) made with concrete having a &taucmax = 2.1 N/mm2. For the reinforcement provided and the grade of concrete used, it may be assumed that the &tauc = 0.75 N/mm2. The design shear in beam P is 400 kN and in beam Q is 750 kN. Considering the provisions of IS 456: 2000, which of the following statements is TRUE?
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- Shear reinforcement should be designed for 175 kN for beam P and the section for beam Q should be revised.
- Nominal shear reinforcement is required for beam P and the shear reinforcement should be designed for 120 kN for beam Q.
- Shear reinforcement should be designed for 175 kN for beam P and the shear reinforcement should be designed for 525 kN for beam Q.
- The sections for both beams P and Q need to be revised.
Correct Option: A
| τv = | = | |||
| bd | 450 × 750 |
= 1.33 N/mm2
τv < τc max (2.1 N/mm2)
∴ shear reinforcement required = τv – τc) bd
= (1.33 – 0.75) × 400 × 750 = 175 kN
| For Q, τr = | = | = 2.5 N/mm2 | ||
| bd | 750 × 400 |
τy >τc max ∴ Revise the section.
