Structural steel

Properties - Structural steel differs from concrete in its compressive strength and tensile strength.

Strength - Structural steel has high strength, stiffness, toughness and ductility, and is one of the most commonly used materials in commercial and industrial buildings.

Constructability - Structural steel can be developed into almost any shape and can be bolted or welded together during construction. Structural steel can be installed as soon as the material arrives on site, while concrete must cure at least 1-2 weeks after placement before construction can proceed, making steel a construction material suitable for schedule.

Fire resistance - Steel is essentially a non-combustible material. However, when heated to the temperatures in the fire scenario, the strength and stiffness of the material are significantly reduced. International building codes require adequate refractory cladding of steel, which increases the overall cost of steel construction.

Corrosion - Steel corrodes when it comes into contact with water, resulting in a potentially hazardous structure. Measures must be taken in steel structural construction to prevent any lifetime corrosion. The steel can be painted to provide water resistance. In addition, refractory materials used to wrap steel are usually waterproof.

Mold - Compared to wood, steel provides a surface environment that is less suitable for mold growth.

Today's tallest structures (often called "skyscrapers" or high-rise buildings) are built using structural steel because of its constructability and high strength-to-weight ratio. In contrast, concrete, though less dense than steel, has a much lower strength-to-weight ratio. This is because structural concrete members require greater volume to support the same load; Steel, though denser, doesn't need as much material to carry the load. However, for low-rise buildings or buildings with more than one story or fewer, this advantage becomes negligible. Low-rise buildings are distributed far less than loaded high-rise structures, making concrete an economical choice. This is especially true for simple structures (such as parking lots) or any simple straight-line shaped building.