Compression members using angle sections: A compression member built from steel angle sections can practically be configured as which of the following?
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AA continuous member (built-in along the length in a frame)
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BA discontinuous single-angle strut (connected at ends)
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CA discontinuous double-angle strut (paired angles back-to-back)
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DAll the above
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ENone of the above
Answer
Correct Answer: All the above
Explanation
Introduction / Context:Angle sections are versatile for compression members in trusses, bracing, and light columns. Their use spans single-angle struts to double-angle and continuous built-up members.
Given Data / Assumptions:
- Structural steel angles may be used singly or paired.
- End connections and effective lengths vary with application.
Concept / Approach:Single-angle struts are common in roof trusses; double-angle struts improve symmetry and reduce eccentricity. Where angles are continuous in frames (e.g., as columns or posts), they become continuous members. All such configurations are recognized in design practice with corresponding slenderness, effective length, and connection detailing rules.
Step-by-Step Solution:
List practical configurations: single-angle, double-angle, continuous.Check end conditions and connection eccentricity (gusset connection often eccentric for single angles).Conclude that all listed configurations are feasible and used.Verification / Alternative check:Design guides and codes include capacity formulas and effective length factors for different angle arrangements and restraint conditions.
Why Other Options Are Wrong:Excluding any configuration would be incorrect because all are standard in practice.
Common Pitfalls:Ignoring eccentricity in single-angle struts; inadequate lacing/tying in built-up columns; overlooking local buckling.
Final Answer:All the above