Compression Members: Identify the correct terminology and behavior for vertical members under axial compression
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AThe structural member subjected to compression and whose lateral dimensions are small compared to its length is called a strut
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BVertical compression members are generally known as columns or stanchions
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CLateral deflection of a long compression member is generally known as buckling
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DAll the above
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ENone of the above
Answer
Correct Answer: All the above
Explanation
Introduction:In structural engineering, compression members are fundamental elements that resist loads pushing toward the member's centroid. This question checks whether you know the standard terminology—struts, columns (stanchions), and the instability phenomenon called buckling—used for members under axial compression.
Given Data / Assumptions:
- Member is subjected primarily to axial compression.
- Terminology is based on conventional structural engineering usage.
- Behavior under compression may include instability (buckling) depending on slenderness.
Concept / Approach:Short, stocky members mainly fail by crushing, while long, slender members can become unstable and buckle before material failure. Names also depend on orientation and usage: the generic term “strut” for compression members; “column” or “stanchion” when vertical and load-carrying in buildings/frames.
Step-by-Step Solution:Step 1: Recognize naming—any member in compression can be called a strut.Step 2: When the compression member is vertical in a structure, standard terms are column or stanchion.Step 3: For sufficiently slender members, lateral deflection under compression is buckling, a stability failure mode.Step 4: Since all three statements are correct, the inclusive option is the right choice.
Verification / Alternative check:Textbooks (strength of materials, structural analysis) consistently define vertical compression members as columns/stanchions and compression members more generally as struts. Euler's analysis predicts buckling in slender columns, confirming statement (c).
Why Other Options Are Wrong:a: Correct but incomplete alone.b: Correct but incomplete alone.c: Correct but incomplete alone.e: Incorrect because multiple statements are correct.
Common Pitfalls:Confusing crushing with buckling; assuming only very tall building members are “columns”; ignoring that “strut” applies regardless of orientation.
Final Answer:All the above.