Material property recall: The Young’s modulus of elasticity of structural steel is typically taken as which standard value?

Introduction / Context:
Young’s modulus (E) for steel is a fundamental material constant used in deflection, stress, and stability calculations across steel and reinforced concrete design (for modular ratio).

Given Data / Assumptions:

• Structural carbon steel of ordinary grade.
• Standard room temperature conditions.

Concept / Approach:

Conventional design adopts E_steel ≈ 2.0 × 10^5 N/mm², which is 200 kN/mm². This approximation is sufficiently accurate for most building and bridge calculations.

Step-by-Step Solution:

Verification / Alternative check:

Many codes and textbooks list the same nominal value; small variations (±5%) do not change the standard selection for exam purposes.

Why Other Options Are Wrong:

150, 250, and 275 kN/mm² deviate significantly from the accepted nominal constant for structural steel.

Common Pitfalls:

Confusing units (N/mm² vs kN/mm²) or using stainless/temperature-dependent values.

Final Answer:

200 kN/mm²