How Long Do Steel Frame Buildings Last?

The development of steel frame structures in China has not been very long. From initially being used in temporary buildings to now being utilized in various settings, steel structures have rapidly gained popularity due to their seismic resistance. While steel structures have many advantages, the lifespan of these buildings remains a concern for many people. Today, we will discuss the lifespan of steel structure buildings and the factors that influence it.

How Long Do Steel Frame Buildings Last?

Generally, the lifespan of steel frame structure buildings ranges from 50 to 80 years, but many factors can influence this lifespan.

The lifespan of an industrial steel frame building mainly depends on its material quality, climate conditions, the temperature and humidity inside the workshop, and whether there are corrosive gases present. If effective maintenance measures such as anti-corrosion, fire prevention, and anti-oxidation are implemented during the construction of an industrial steel frame building, its lifespan can be significantly extended. The lifespan of an industrial steel frame building is affected by environmental conditions, local climate conditions, and maintenance conditions.

Factors Affecting the Lifespan of Steel Structure Houses:

This section will discuss how to extend the lifespan of steel frame structure buildings by examining the factors that influence their longevity.

1. Material Quality

The steel used in steel frame structures mainly includes ordinary carbon structural steel and low alloy structural steel, each having different impacts on the building's lifespan.

Ordinary Carbon Structural Steel

Ordinary carbon steel is generally more economical due to its simple production process compared to other types of steel. This type of steel has high strength and durability, making it suitable for structures that need to bear heavy loads.

However, ordinary carbon steel is prone to corrosion, so when used in humid or corrosive environments, additional protective coatings may be necessary to extend its lifespan. Due to its relatively high carbon content, ordinary carbon steel can be brittle, requiring special attention in design and construction to avoid fractures caused by excessive stress.

Low Alloy Structural Steel

Low alloy structural steel enhances corrosion resistance and oxidation resistance by adding other alloying elements such as chromium and nickel, making it perform better in harsh environments. This type of steel typically has higher strength and toughness, allowing it to withstand greater stress and deformation.

Due to its excellent corrosion resistance, low alloy structural steel has lower maintenance costs and a longer lifespan when used in humid or corrosive environments. Its high strength and toughness enable it to maintain structural integrity under extreme conditions such as earthquakes, thereby extending the building's lifespan.

2. Corrosion Resistance

With advantages come disadvantages, and for steel structures, a notable drawback is their relatively poor corrosion resistance, which can impact the lifespan of the building.

What Factors Contribute to the Corrosion of Steel Structures?

• Humidity and Temperature: Atmospheric humidity and temperature are significant factors affecting the corrosion of steel structures. In high-humidity environments, a water film can easily form on the steel surface, accelerating the electrochemical corrosion process.

• Air Pollutants: Atmospheric pollutants such as sulfur dioxide and chlorides can accelerate the corrosion of steel, especially in industrial areas or coastal regions.

To improve the corrosion resistance of steel structure buildings and extend their lifespan, one can focus on the selection of materials and coatings. Using corten steels or alloy steels can enhance corrosion resistance because these steels contain alloying elements like chromium and nickel that form a protective oxide layer.

High-quality anti-corrosion coatings, such as epoxy or polyurethane paints, can also effectively isolate corrosive media and extend the life of the steel. The thickness and uniformity of the coating also directly affect its protective effectiveness.

3. Fire Resistance

Although steel structures themselves do not burn, this does not mean that fire safety can be ignored. If a steel structure building is exposed to high temperatures for an extended period, it can significantly affect its structural stability. Once the temperature reaches a critical point, collapse may occur.

Different types of steel exhibit significant differences in fire resistance, primarily due to variations in melting points and coefficients of thermal expansion. These characteristics directly impact the performance of steel in high-temperature environments.

Ordinary Carbon Structural Steel

• Lower Melting Point: Carbon steel has a relatively low melting point, making it prone to softening under high temperatures, which results in poor fire resistance.

• Higher Thermal Expansion Coefficient: During a fire, carbon steel expands rapidly, which can lead to structural deformation or failure.

Low Alloy Structural Steel

• Higher Melting Point: Alloy steels typically contain elements such as chromium and nickel, which increase the melting point of the steel, allowing it to maintain structural integrity for a longer period under high temperatures.

• Better Fire Resistance: Due to their diverse chemical composition, alloy steels generally offer better fire resistance and can provide longer protection during a fire.

The steel type affects the choice of fireproof coatings and other protective measures. For instance, alloy steel may require a thinner fireproof coating, while carbon steel might need a thicker coating to achieve the same fire resistance rating. Selecting the appropriate fireproof coating, such as thick-film, thin-film, or ultra-thin intumescent coatings, can further enhance the fire resistance of different types of steel.

Improving the fire resistance of steel and its coatings can significantly enhance the performance of steel frame structure buildings during a fire, thereby extending their lifespan.

4. Construction Quality

Construction quality issues are related to the professionalism of the building team, as well as the specifications and load-bearing capacity of the steel. Given past collapse incidents reported, it is recommended to choose a professional team for construction and pay attention to the following key aspects:

• Welding Quality: Welding is a critical part of steel structure construction, directly affecting the overall strength and stability of the structure. High-quality welding techniques can ensure strong connections, reduce stress concentration, and thus extend the building's lifespan. Using modern technology to inspect weld seams for defects can prevent potential structural failures.

• Construction Precision: Construction personnel must accurately understand and execute design drawings to ensure all components are correctly installed. Misinterpretation of drawings during construction can lead to structural instability or insufficient load-bearing capacity. Precise installation and alignment of components can reduce stress concentration and potential structural issues, thereby enhancing the building's durability.

• Material Handling: During construction, the treatment of steel surfaces (such as sandblasting or shotblasting) is crucial for the adhesion of coatings and corrosion resistance. Good surface treatment can effectively extend the lifespan of steel. Ensuring that materials are not damaged or corroded during storage and transportation can prevent quality issues later in construction.

How to Properly Maintain Steel Structures in Daily Life?

The surface of steel structures must be kept clean and dry. Areas prone to dust accumulation, such as steel column bases and outside of panels, should be cleaned regularly. Regularly inspect the integrity of protective coatings on steel structures. Maintenance is necessary when 90% of the coating surface loses its gloss, 25% of the surface becomes rough, weathered, or cracked, or when 40% of the component shows slight rusting.

Steel components affected by high temperatures should be equipped with protective panels to prevent damage to the coatings from heat. Avoid contact between components and corrosive substances; if contact occurs, clean promptly. To improve fire resistance, a good protective method is to add metals such as Mo (molybdenum) and Nb (niobium) to the steel, reduce sulfur and phosphorus content, and then apply appropriate external treatments to extend the building's lifespan.

Conclusion

The lifespan of steel frame structures is influenced by various factors, including environmental conditions, material quality, design, and construction quality. By performing regular maintenance, selecting high-quality materials, and strictly controlling construction quality, the lifespan of steel frame structures can be effectively extended. It is recommended to pay attention to these factors when purchasing and using steel frame structures to ensure their stability and safety.