R.C.C. slab detailing: For a slab with main reinforcement diameter 16 mm, select the minimum nominal clear cover to main bars as per common building practice.

Introduction / Context:Clear cover in slabs protects steel from corrosion and fire and ensures proper bond. Many design practices (e.g., IS 456 guidance) adopt a minimum nominal cover of 15 mm or the bar diameter, whichever is greater, for mild exposure slabs.

Given Data / Assumptions:

• Main bar diameter = 16 mm.
• Slab in typical building exposure (not aggressive).
• Adopt rule: cover = max(15 mm, bar diameter).

Concept / Approach:

Choose the higher of 15 mm and 16 mm to satisfy durability and cover tolerances in slabs.

Step-by-Step Solution:

Verification / Alternative check:

If exposure is severe, higher cover may be required; for normal exposure, 16 mm satisfies the common minimum requirement.

Why Other Options Are Wrong:

12–15 mm are less than the bar diameter; they do not satisfy the max(15 mm, bar dia) rule for a 16 mm bar.

Common Pitfalls:

Confusing slab cover with beam cover; ignoring exposure class adjustments.

Final Answer:

16 mm