A concrete beam, 600 mm wide and 700 mm deep, is simply supported over a length of 6 m. The beam has six 20 mm reinforcing bars placed at 60 mm from the base of the beam. The load on the beam is 16 kN/m, including the weight of the beam.

Calculate the stress in the steel and the concrete if the modular ratio is 15.

Answer :

The stress in the steel and the concrete is 71.67 MPa and 0.215 MPa, respectively.

Width of concrete beam, b = 600 mm

Depth of concrete beam, d = 700 mm

Reinforcement provided, diameter of bars = 20 mm,

Distance from the bottom face of the beam = 60 mm

Load on the beam = w = 16 kN/m

Modular ratio = m = 15

The cross-sectional area of one bar = (π/4) × (20)² = 314.16 mm²

Total area of steel = 6 × 314.16 = 1884.96 mm²

Area of concrete = Width × Depth - Area of steel

= 600 × 700 - 1884.96

= 414.04 × 10⁴ mm²

Stress in steel (σ_s) can be calculated using the following relation:

σ_s/E_s = σ_c/E_c×m

Where σ_c = Stress in concrete

E_c = Modulus of elasticity of concrete

E_s = Modulus of elasticity of steelσ_s

= (σ_c × m × E_s)/E_cσ_c

= (w × L)/[(b × d) - A_s] + ((σ_s × A_s)/A_c)σ_c

= (16 × 6)/[600 × 700 - 1884.96] + [(σ_s × 1884.96)/(414.04 × 10⁴)]σ_c

= 0.215 MPaσ_s = (σ_c × E_c)/[m × E_s]σ_s

= (0.215 × 10⁶)/(15 × 200 × 10³)σ_s

= 71.67 MPa

Learn more about Modular ratio from the given link

https://brainly.com/question/33146776

#SPJ11