The unit weight of the concrete is 2500 kg/m³. The allowable stress in tension in cement concrete is 0.8 kg/cm². The coefficient of friction is 1.5. Estimate the spacing between the contraction joint for plain cement concrete slab.
- A3.67 m
- B4.27 mCorrect
- C4.87 m
- D5.47 m
Solution
Concept
Spacing of contraction joints
Formula
L = 2 S / (W f)
Step-by-step solution
1. L = 2 × 0.8 × 10⁴ /(2500 × 1.5) = 4.27 m.
Explanation
The tensile stress balances friction.
Why the other options are wrong
Others do not follow.
Shortcut
L = 2S/(γ f).
Correct answer: B) 4.27 m