A compression member is termed a column or strut if the ratio of its effective length to its least lateral dimension is more than:
Try it first: pick an option, then read the explanation.
Correct answer: C. 3
Asked in SSC JE 2012
Detailed Explanation
IS 456 (clause 25.1.1) defines a column as a compression member whose effective length exceeds three times its least lateral dimension. Shorter members are pedestals.
Why “3” Is Correct
The limiting ratio is 3.
| le / least lateral dimension | Member (IS 456) |
|---|---|
| ≤ 3 | Pedestal |
| > 3 and < 12 | Short column |
| ≥ 12 | Long (slender) column |
Why the Other Options Are Wrong
- A. 1: 1 is far too low — almost every block would be a column.
- B. 2: 2 is not the code limit.
- D. 5: 5 is not the code limit.
Key Point
le/D > 3 → column; ≤ 3 → pedestal; ≥ 12 → slender column (IS 456).
Key Concepts for Students
- A strut is an inclined or horizontal compression member (e.g. in a truss).
- Short columns (3 to 12) fail mainly by crushing.
- Slender columns need additional moment for buckling effects.
Practice more: this is question 29 in Columns and Struts MCQs – Part 2. Try the whole set and check every answer instantly.