For design calculations, the modulus of elasticity of steel (Es) is generally assumed as Choose the most appropriate standard value and unit.
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A200 kN/mm²
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B225 kN/mm²
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C250 kN/mm²
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D275 kN/mm²
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E150 kN/mm²
Answer
Correct Answer: 200 kN/mm²
Explanation
Introduction:The elastic modulus of reinforcing steel is a fundamental property used in deflection, crack width, and composite action checks. Designers typically adopt a standard value suitable for most carbon steel rebars.
Given Data / Assumptions:
- Carbon steel reinforcement used in normal temperature ranges.
- Linear elastic behavior assumed up to yield for serviceability checks.
Concept / Approach:
For structural design, Es is taken as approximately 200,000 N/mm², which is equivalently 200 kN/mm². This value aligns with material test data and code recommendations.
Step-by-Step Solution:
1) Recognize that 1 kN/mm² = 1000 N/mm².2) Standard Es = 200,000 N/mm² = 200 kN/mm².3) Select the exact matching option.Verification / Alternative check:
Material certificates for Fe415/Fe500 typically report Es near 200 GPa, confirming the chosen value.
Why Other Options Are Wrong:
225, 250, 275, and 150 kN/mm² do not reflect the standard modulus used in design and would misstate stiffness.
Common Pitfalls:
Confusing yield strength (e.g., 500 MPa) with modulus; mixing units of GPa, N/mm², and kN/mm².
Final Answer:
200 kN/mm²