Riveted joints – simple plate-tearing efficiency in terms of pitch and hole diameter If p is the rivet pitch and d is the gross hole diameter, the joint efficiency with respect to plate tearing (neglecting rivet shear/bearing) is:

Introduction / Context:
Joint efficiency compares the strength of a riveted (or bolted) joint to that of the unperforated plate. One basic check is plate tearing across a pitch length—important when evaluating longitudinal joints in tanks, boilers, and plate girders.

Given Data / Assumptions:

• Single-row riveted joint in a uniform plate.
• Plate tearing considered over one pitch length p.
• Rivet hole diameter (gross) is d.
• Ignore rivet shear and bearing for this simplified efficiency expression.

Concept / Approach:
Net section width resisting tension across the pitch line is (p − d). The unperforated (gross) section width is p. With constant plate thickness and tensile strength, efficiency against plate tearing is the ratio of net to gross section area.

Step-by-Step Solution:
Net area / Gross area = (p − d) / pTherefore, η = 1 − d/p

Verification / Alternative check:
Including multiple rows or staggered holes modifies the net-section calculation by adding or subtracting diagonal ligament effects, but the single-row, straight-pitch case reduces to η = 1 − d/p.

Why Other Options Are Wrong:

• d/p or p/d do not represent a net/gross area ratio for tearing.
• (p − 2d)/p corresponds to two holes per pitch line, not this case.
• (p − d)/(p + d) has no basis in net-section derivation.

Common Pitfalls:
Using nominal rivet diameter instead of hole diameter (which is larger); always use gross hole size when finding the net section.

Final Answer:
η = 1 − d/p