Sizing riveted connections – determining the number of rivets required In routine working-stress design, the number of rivets to be provided in a joint is determined by which basic relation?

Introduction / Context:
Connection design ensures that the shear transfer between members is adequate. In riveted (or bolted) joints, a simple capacity check is used to size the number of fasteners based on the demand and the strength of a single fastener.

Given Data / Assumptions:

• Total load to be carried by the joint is known.
• Design shear (or bearing) capacity of one rivet is known for the selected diameter and materials.
• Governing failure mode for a single rivet is identified (shear or bearing).

Concept / Approach:
The basic sizing rule is demand over capacity, then round up. Distribution and eccentricities may require additional checks, but the initial count is controlled by the one-rivet design capacity in the governing mode.

Step-by-Step Solution:
Find single-rivet design strength (shear or bearing).Compute required count = total joint load / single-rivet strength.Round up to the next whole number; then check spacing, edge distance, and secondary effects.

Verification / Alternative check:
Where eccentric loading exists, rivet group analysis (resultant shear, polar moment) supplements the initial count.

Why Other Options Are Wrong:

• Relations using plate thickness, pitch, or tributary area do not directly determine strength.
• Bending moment divided by pitch is not a capacity-based count.

Common Pitfalls:
Not checking edge distance/pitch limits or bearing on plates after counting rivets can cause detailing failures.

Final Answer:
Number of rivets = factored load on the joint divided by the design shear strength of one rivet in the governing failure mode, rounded up to the next whole number