In steel connections, the minimum pitch (center-to-center distance) between rivet holes should not be less than what multiple of the hole diameter?

Introduction / Context:
Pitch limits in riveted (and analogous bolted) joints ensure adequate material between holes for load transfer, reduce stress concentration, and maintain constructability. The minimum pitch prevents hole overlap, lamellar tearing, and edge splitting during fabrication and service.

Given Data / Assumptions:

• Pitch p is the center-to-center spacing between adjacent holes along the line of fasteners.
• Hole diameter includes drilling allowance over nominal rivet diameter.
• We seek the standard minimum multiple of hole diameter.

Concept / Approach:

Design practice specifies a lower bound: p ≥ 2.5 * d_hole. This gives enough ligament area for shear and tension and accommodates fabrication tolerances while avoiding cracking during driving or tightening.

Step-by-Step Solution:

Verification / Alternative check:

Guides also impose maximum pitch limits to prevent plate buckling and ensure force sharing; however, the question addresses only the minimum, which is 2.5 * d_hole.

Why Other Options Are Wrong:

• 1.5 or 2.0: Too small; risks weakened ligaments and fabrication issues.
• 3.0: Acceptable but not the mandated minimum; it is more than necessary.
• None: Incorrect because a standard minimum exists.

Common Pitfalls:

• Confusing pitch with edge distance (from hole center to plate edge).
• Using nominal rivet diameter instead of hole diameter, which underestimates pitch.

Final Answer:

2.5 times the hole diameter