Riveted joints – shear condition:\nIn a double-strap butt joint with equal cover straps on both sides, the rivets are in which shear condition?

Introduction / Context:
Riveted butt joints use cover plates (straps) to connect the main plates. The number and placement of straps control the load path through rivets and thus whether the rivets experience single shear or double shear. Recognizing this is essential for calculating joint efficiency and rivet strength.

Given Data / Assumptions:

• Butt joint with two equal cover straps, one on each side of the main plates.
• Load is axial, transmitted symmetrically through straps.
• Neglect secondary bending due to eccentricity of load path.

Concept / Approach:
With two cover straps, load from one main plate to the other splits into two parallel shear planes across each rivet shank. The rivet is thus cut by two shear planes (one to each strap), placing it in double shear. This doubles the nominal shear area compared to single-strap configurations, increasing rivet shear capacity.

Step-by-Step Solution:

Verification / Alternative check:
Compare to a single-strap butt joint: there is only one strap and one shear plane through each rivet, resulting in single shear. Adding the second strap creates the second shear plane.

Why Other Options Are Wrong:

• Single shear / either-or: contradict the symmetric two-strap configuration.
• Never in shear / torsion: rivets primarily carry shear in these joints; torsion is not a basic design action here.

Common Pitfalls:
Forgetting eccentric load distribution if straps are unequal; with equal straps and proper fit, double shear is the governing idealization.

Final Answer:
Always in double shear