Removal of props under slabs spanning up to 4.5 m is
- A3 days
- B7 daysCorrect
- C14 days
- D21 days
Solution
Concept
Stripping time of props (IS 456)
Step-by-step solution
1. IS 456: props to slabs spanning up to 4.5 m are removed after 7 days (3 days for the formwork sides).
Explanation
Props are left until the concrete gains enough strength.
Why the other options are wrong
3 days is for vertical formwork; 14 and 21 days apply to longer spans.
Shortcut
Slab ≤ 4.5 m: 7 days; > 4.5 m: 14 days.
Correct answer: B) 7 days