Riveted joint design – number of rivets required A joint uses rivets with strengths (per rivet) of 3425 kg in single shear, 4575 kg in bearing, and 5025 kg in tearing of the connected plate. If the member must carry 35 tonnes, how many rivets are required?

Introduction / Context:
In riveted (or bolted) connections, the usable capacity per fastener is the least of the shear capacity of the fastener, the bearing capacity against the plate, and the net-section tearing capacity of the plate. The total number of fasteners is determined by dividing the required factored load by this governing (minimum) capacity.

Given Data / Assumptions:

• Shear strength per rivet = 3425 kg.
• Bearing strength per rivet = 4575 kg.
• Tearing strength per rivet (plate) = 5025 kg.
• Total load = 35 tonnes = 35000 kg.

Concept / Approach:
The limiting (governing) mode is the one with the smallest capacity. The design number of rivets n is the smallest integer such that n * Rmin ≥ total load.

Step-by-Step Solution:

Verification / Alternative check:
Check total shear capacity with 11 rivets: 11 * 3425 = 37675 kg ≥ 35000 kg → OK.

Why Other Options Are Wrong:
10 gives only 34250 kg, which is less than 35000 kg; 12, 13, 15 are conservative but not the minimum meeting the requirement.

Common Pitfalls:
Using average of capacities instead of the minimum; forgetting to convert tonnes to kg; rounding down instead of up.

Final Answer:
11