The factor of safety against sliding in the case of abutments subjected to various forces should be greater than _______
- A1
- B1.5Correct
- C2
- D2.5
Solution
Concept
Abutments must be safe against sliding, overturning and bearing failure.
Formula
FOSsliding = μ ΣV / ΣH
Step-by-step solution
1. Check the factor of safety against sliding: FOS = μ ΣV / ΣH. 2. Common design values: FOS for sliding is 1.5 under normal loads (IRC 78 gives 1.5 for sliding and 2.0 for overturning).
Explanation
Typical codes require FOS against sliding of about 1.5 for normal loads.
Shortcut
Sliding FOS about 1.5, overturning about 2.
Common mistake
Mixing sliding FOS (1.5) with overturning FOS (2).
Correct answer: B) 1.5