Riveted joints basics: A lap joint is always subjected to which shear condition under load transfer?

Introduction / Context:
Riveted joints transfer loads through shear in the rivets. Joint configuration dictates whether each rivet is in single or double shear. Understanding this is fundamental in design of plate, boiler, and structural joints.

Given Data / Assumptions:

• Lap joint with two plates overlapping and a single row (or multiple rows) of rivets passing through the overlap.
• Load is axial, trying to slide one plate relative to the other.
• Plates remain in a single overlapping plane (no cover plate on the opposite side).

Concept / Approach:
In a lap joint, each rivet crosses one shear plane at the lapped interface. Therefore, each rivet resists load in single shear. In contrast, a double-strap butt joint places rivets in double shear because the force passes through two shear planes (two strap interfaces).

Step-by-Step Solution:

Verification / Alternative check:
Sketch the free-body diagram of the plates and locate the interface; only one shear plane intersects the rivet for each load path in a lap configuration.

Why Other Options Are Wrong:
Double shear arises in double-strap butt joints, not in lap joints. Pure bending only or “no load on rivets” is incorrect in a loaded lap joint. Alternating shear conditions do not occur in a single, uniform lap geometry.

Common Pitfalls:
Confusing lap joints with butt joints; assuming two planes exist because of two plates—only the overlapping interface matters here.

Final Answer:
Single shear