If maximum design discharge is 0.3 m3/sec, then the vertical clearance required for Road Bridge above the HFL is _______
- A75 mm
- B100 mm
- C150 mmCorrect
- D250 mm
Solution
Concept
Vertical clearance above HFL depends on the design discharge.
Step-by-step solution
1. The design discharge is 0.3 m³/s. This is very small. 2. IRC practice gives the smallest clearance for discharge up to 0.3 m³/s. 3. The clearance is measured from HFL to the lowest point of the bridge deck soffit. 4. Clearance increases as discharge increases. 5. For 0.3 m³/s the value is 150 mm
Shortcut
Smaller discharge = smaller clearance.
Correct answer: C) 150 mm