What member count characterizes a structurally rigid framed assembly________________?
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Answer: A. 2n-3
Explanation
A structurally rigid framed truss assembly requires a precise ratio of members to joints. The minimum member count needed to prevent internal collapse is given by two n minus three. Here n represents the total number of pin-connected joints in the framed structure. Trusses are engineered structures made of straight members connected at joint nodes. If members are fewer than two n minus three, the truss is geometrically unstable and underdetermined. Triangulation provides structural rigidity because triangles cannot deform without member bending.
Civil engineers apply this formula when designing bridge trusses and roof support frameworks. Ensuring structural rigidity prevents catastrophic collapse under heavy live and dead loads. Building safety codes require proper truss geometry for all public infrastructure projects. Option B represents a chain formula insufficient for rigid two-dimensional truss frames. Option C overestimates the required member count for basic triangular stability. Options D and E provide incorrect algebraic formulas that fail determinacy checks.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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