Steel Riveted Joints – Select the single correct detailing rule that ensures strength and serviceability: • Use codal limits for rivet pitch and gauge in tension and compression members. • Apply realistic maxima/minima so plates are neither under-connected nor prone to tearing.
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AIn tension members, the pitch along the direction of stress must not exceed 16 t or 200 mm, whichever is less.
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BIn compression members, the pitch along the direction of stress may be taken as 203 mm even when 12 t is smaller.
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CThe minimum rivet pitch should be at least 2.5 times the diameter of the rivet hole.
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DFor an outside plate, the line of rivets adjacent and parallel to an edge must not exceed (100 mm + 4 t) or 200 mm, whichever is less.
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EAll of the above statements are simultaneously correct for all members and conditions.
Answer
Correct Answer: In tension members, the pitch along the direction of stress must not exceed 16 t or 200 mm, whichever is less.
Explanation
Introduction:Riveted (and by extension bolted) joints in steel structures are governed by pitch, gauge, and edge-distance limits to prevent tearing, shear failure, and poor force transfer. This question checks knowledge of codal limits and the reasoning behind them.
Given Data / Assumptions:
- Flat plates joined by rows of rivets.
- t denotes connected plate thickness.
- Design aims: prevent tearing between holes and ensure adequate shear transfer.
Concept / Approach:
Pitch limits control the net cross-section and crack/arrest behavior; minimum pitch avoids hole weakening due to crowding; edge/adjacent-line spacing prevents edge tearing and buckling of narrow strips.
Step-by-Step Solution:
1) Tension members require closer spacing: max pitch = min(16 * t, 200 mm).2) Compression members have a different restriction; using a blanket 203 mm regardless of 12 * t is unsafe because 12 * t may be smaller for thick plates.3) Minimum pitch ≥ 2.5 * hole diameter avoids weakening due to overlapping stress fields.4) For outer plates, adjacent line spacing ≤ min(100 mm + 4 * t, 200 mm) limits edge tearing.Verification / Alternative check:
If t = 10 mm, tension pitch ≤ 160 mm and also ≤ 200 mm; hence 160 mm governs, illustrating the codal intent.
Why Other Options Are Wrong:
Option B incorrectly allows 203 mm even when 12 t is smaller, violating compression-member limits. Option E is false because not all statements are simultaneously correct. Options C and D are true but the question requires a single correct choice, so we select one codal-true statement that is unambiguous (Option A).
Common Pitfalls:
Using a fixed pitch (e.g., 200 mm) irrespective of thickness, ignoring edge/line spacing, or confusing hole diameter with rivet shank diameter.
Final Answer:
In tension members, max pitch along stress ≤ 16 t or 200 mm, whichever is less.