A concrete column with a 200 × 200 mm cross-section is reinforced with four steel bars totaling 1200 mm2 in cross-sectional area. Determine the safe load for this column if the allowable concrete stress is 5 N/mm2 and Es equals 15 Ec________________?
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Answer: C. 284 MN
Explanation
Using modular ratio transformations for reinforced concrete columns yields the total safe load capacity. Multiplying steel area by the modular ratio converts the steel reinforcement into an equivalent concrete area. Summing the effective areas and multiplying by allowable concrete stress calculates the safe load capacity. Reinforced concrete combines concrete strong in compression with steel bars strong in tension and compression. Modular ratio represents the ratio of steel elastic modulus to concrete elastic modulus. Composite columns share applied loads proportional to their respective cross-sectional areas and stiffnesses.
High-rise buildings utilize reinforced concrete columns to support massive dead and live structural loads safely. Modular ratio design ensures that neither concrete nor steel exceeds its allowable stress limit under service loads. Structural engineers rely on transformed section analysis to design composite building columns accurately. Option A utilizes an incorrect force summation that does not match standard composite column transformations. Option B miscalculates the contribution of the steel reinforcement area multiplied by the modular ratio. Option D overestimates the composite column load capacity by ignoring proper transformed area reductions.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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