Question

The diameter of the lateral ties in a column shall in no case be less than

• A. \(12\,\mathrm{mm}\)
• B. \(16\,\mathrm{mm}\)
• C. \(6\,\mathrm{mm}\)
• D. \(20\,\mathrm{mm}\)

Hint:

IS 456:2000 specifies \[ \boxed{ \phi_{\text{tie}} \ge 6\,\mathrm{mm} } \] and in some cases not less than one-fourth of the largest longitudinal bar diameter.

Answer 1

The Correct Option is C

Step 1: Role of a lateral tie.
A lateral tie wraps around the main bars of a column and holds them together, confining the concrete core and stopping the longitudinal bars from buckling sideways once the column is loaded.
Step 2: The floor value set by the code.
IS 456:2000 says the tie diameter must be at least one quarter of the largest longitudinal bar diameter, but it also fixes an absolute lower bound so that even for small bar sizes the tie is not made unrealistically thin. That absolute lower bound is $6\,\text{mm}$.
Step 3: Picking the answer.
Of the given choices, $6\,\text{mm}$ is the smallest permissible diameter allowed by the code; $12\,\text{mm}$, $16\,\text{mm}$ and $20\,\text{mm}$ are all larger than this floor value.
\[ \boxed{6\,\text{mm}} \]