1. High strength and light weight.

Steel has high strength and high elastic modulus. Compared with concrete and wood, the density and strength of steel are relatively low, so steel structural members have small cross-section, light weight, convenient transportation and installation, and are suitable for structures with large span, high height and large bearing weight.

2. Good toughness and reliability.

Steel is suitable for bearing impact and dynamic loads, and has excellent seismic performance. Its internal structure is homogeneous and nearly isotropic. The actual working performance is more in line with the calculation theory. Therefore, the steel structure has high reliability.

3. High degree of mechanization.

Steel structural members are easy to be manufactured in the factory and assembled on site. The finished steel structural members have high precision, high production efficiency, fast assembly speed and short construction period. Steel structure is the most industrialized structure.

4. The steel structure has good sealing performance.

Since the steel structure is a welded structure, it can be completely sealed to make high-pressure vessels, large oil pools, pressure pipes, etc. with good air tightness and water tightness.

5. The steel structure is heat-resistant but not fire-resistant.

When the temperature is lower than 150 ℃, the properties of steel change little. Therefore, the steel structure is suitable for the hot workshop, but when the surface of the structure is exposed to the heat radiation of about 150 ℃, it should be protected with insulation plates. When the temperature is 300 ℃ - 400 ℃, the strength and elastic modulus of the steel decrease significantly. When the temperature is about 600 ℃, the strength of the steel will tend to zero. In buildings with special fire protection requirements, refractory materials must be used for protection to improve the fire resistance rating.

6. Poor corrosion resistance.

Steel is easy to rust in humid and corrosive environment. General steel shall be derusted, galvanized or coated, and shall be maintained regularly. For offshore platform structures in seawater, special measures shall be taken to strengthen corrosion resistance.

7. Green and environmental protection.

Demolition of steel structure buildings will hardly produce construction waste, and its steel can be recycled, which is very environmentally friendly.