According to IS:800 (1971), what is the minimum edge distance required for a rivet line connecting two or more plates, expressed as 37 mm plus a function of the thickness t (in mm) of the thinner outside plate?

Introduction / Context:
Edge distance in riveted (or bolted) joints is the minimum center-to-edge clearance that prevents plate tearing and ensures proper force transfer. IS:800 (1971) prescribes a baseline edge distance augmented by a thickness-dependent allowance so the connection remains ductile and construction-friendly.

Given Data / Assumptions:

• Standard: IS:800 (1971) working-stress era provisions.
• Rivet line connecting two or more plates.
• t = thickness (mm) of the thinner outside plate.

Concept / Approach:
The codal intent is to avoid splitting at the plate boundary and to keep sufficient material around the hole. For thicker plates (usually larger rivet diameters), the edge distance must increase. IS:800 captures this with a simple linear rule of the form base value + multiplier * t.

Step-by-Step Solution:
Identify the relevant clause for minimum edge distance for rivet lines.Apply the codal expression: e_min = 37 mm + 4t.Interpretation: for t = 10 mm, e_min = 37 + 4*10 = 77 mm.

Verification / Alternative check:
Design handbooks and classroom examples align with the same rule, which scales proportionally with thickness and matches practical shop tolerances for drilling/punching and edge finishing.

Why Other Options Are Wrong:

• 37 mm + 2t: Too small; risks edge tearing for thicker plates.
• 37 mm + 6t, 8t, 10t: Overly conservative and uneconomical without codal basis.

Common Pitfalls:

• Confusing edge distance with end distance (end distance is measured from plate end, not edge).
• Using clear hole instead of gross (nominal) diameter when checking spacing rules—here the codal rule is directly in terms of t.

Final Answer:
37 mm + 4t