Question

The design shear strength of a reinforced concrete rectangular beam with a width of 250 mm and an effective depth of 500 mm, is 0.3 MPa. The torsional moment capacity of the section (in kN.m) under pure torsion, as per IS 456:2000, is __________ (round off to one decimal place).

Hint:

Ensure all values are in consistent units before applying IS 456:2000 design formulas for torsion.

Answer 1

Correct Answer: 5.7

Given: Width, \( b = 250 { mm} \)
Effective depth, \( d = 500 { mm} \)
Design shear strength, \( \tau_c = 0.3 { N/mm}^2 \)
Step 1: Calculate shear force, \[ V_e = \tau_c \cdot b \cdot d = 0.3 \times 250 \times \frac{500}{1000} = 37.5\ {kN} \] Step 2: Use IS 456:2000 torsion formula, \[ T_u = \frac{V_e \cdot b}{1.6 + \frac{1.67 b}{d}} = \frac{37.5 \times 0.25}{1.6} = 5.86\ {kN.m} \] Hence, the torsional moment capacity is \(\boxed{5.86\ {kN.m}}\).