For standard structural cases, the stiffness requirement of a simply supported beam is met if the span-to-overall-depth ratio does not exceed________________?
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Answer: C. 20
Explanation
For standard structural cases, deflection control and stiffness requirements for a simply supported beam are met if the span to overall depth ratio does not exceed twenty. Limiting the span to depth ratio prevents excessive sagging and cracking under long term service loading conditions. Building codes establish this empirical ratio to ensure structural members possess adequate rigidity without requiring complex deflection calculations. Beam stiffness governs how much a structural member deflects under applied loads during its operational lifespan. Excessive beam deflections can cause unsightly cracking in partition walls and damage brittle finishes applied to ceilings. Simply supported beams experience maximum deflections at their mid span locations due to bending moments.
A span to depth ratio of ten represents an excessively deep and stiff beam that is usually uneconomical for standard buildings. Fifteen provides a conservative stiffness ratio that exceeds minimum requirements but may consume unnecessary construction materials. Twenty five exceeds the standard safe limit for simply supported beams, risking excessive deflections and serviceability failures.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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