When floor slabs rest on reinforced cement beams, the ratio of the end span to the intermediate span is kept at______________?
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Answer: C. 0.9
Explanation
To account for continuity effects, the ratio of end span to intermediate span in continuous floor slabs is kept around 0.9. End spans experience different boundary restraint compared to interior spans, necessitating a slightly shorter span length for equilibrium. Maintaining this 0.9 ratio helps balance bending moments across adjacent supports in multi-span continuous concrete floor systems. Continuous floor slabs span over multiple supports, creating negative bending moments over interior beams and positive moments mid-span. Restraint provided by exterior edge beams differs significantly from the symmetric restraint experienced by interior support beams. Standardized span ratios simplify analysis and ensure uniform deflection behavior under standardized uniform service live loads.
Option A suggests a ratio of 0.7, which introduces overly conservative span reductions that complicate architectural room layouts. Option B proposes 0.8, which is sometimes used for specific heavy industrial loadings but deviates from standard practice. Option D provides a ratio of 0.6, representing an extreme reduction that is economically unviable for typical construction.
- Subject
- Engineering
- Category
- Civil Engineering
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- —
- Difficulty
- medium
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