Structural Steel

Structural Steel

Structural steel is a category of steel used for making construction materials in a variety of shapes.

Grades and Types (ASTM)

• ASTM A36: Carbon Structural Steel (36 ksi yield). The most common grade for shapes, plates, and bars.
• ASTM A572: High-Strength Low-Alloy Columbium-Vanadium Structural Steel (Grade 50).
• ASTM A992: Standard Specification for Structural Steel Shapes (Grade 50). The preferred material for wide-flange beams.

Mechanical Properties

• Yield Strength ($F_y$): The stress at which a material begins to deform plastically.
• Tensile Strength ($F_u$): The maximum stress that a material can withstand while being stretched or pulled.
• Modulus of Elasticity ($E$): 29,000 ksi (200 GPa).
• Poisson's Ratio ($\nu$): 0.3.
• Coefficient of Thermal Expansion ($\alpha$): $6.5 \times 10^{-6} /^\circ F$ ($11.7 \times 10^{-6} /^\circ C$).

Tension Test (ASTM A370)

A standard specimen is subjected to axial tension until failure.

Corrosion and Protection

• Atmospheric Corrosion: Reaction with oxygen and moisture.
• Galvanic Corrosion: Contact between dissimilar metals.
• Protection: Painting, Galvanizing (Zinc coating), Weathering Steel (A588).