A cement concrete pavement of thickness 25 cm has two lanes of 7.2 m with a longitudinal joint along the centre. The value of allowable working stress in tension is 1800 kg/cm². Assume unit weight of concrete = 2400 kg/m³ and coefficient of friction = 1.5. Estimate the area of steel per meter of longitudinal joint.
- A1.2 cm² /m
- B1.5 cm² /m
- C1.8 cm² /mCorrect
- D2.1 cm² /m
Solution
Concept
Tie bars
Formula
As = b h γ f / s
Step-by-step solution
1. W = 0.25 × 2400 = 600 kg/m². 2. Width = 3.6 m; force = 3.6 × 600 × 1.5 = 3240 kg/m. 3. As = 3240/1800 = 1.8 cm²/m.
Explanation
Steel resists friction under the slab.
Why the other options are wrong
Others do not follow.
Correct answer: C) 1.8 cm² /m