Structural Materials: Properties and Behavior

Structural steel has a yield strength of approximately 250-350 MPa and is equally strong in tension and compression, unlike most building materials. Its key property is ductility—the ability to deform significantly before fracturing—which makes steel structures highly resilient in earthquakes. Steel members are manufactured as wide-flange beams (I-shapes), hollow structural sections (tubes), channels, and angles. Connections use high-strength bolts or welds. Steel's weakness is fire: it loses half its strength at around 550°C, so fire protection coatings or encasement in concrete are essential.