How the durability of steel structures can be improved

2025-04-17 09:18:33

The durability of a Steel Structure is its ability to maintain its performance, function and appearance during long-term use. Steel structures are widely used in buildings, bridges, ships, towers, etc. However, due to their exposure to various environmental conditions, they are susceptible to corrosion, fatigue, stress corrosion cracking, etc., which reduces their durability. Therefore, enhancing the durability of steel structures is an important engineering issue. The following is a detailed discussion on how to enhance the durability of steel structures from the aspects of material selection, design optimisation, protective measures, construction quality and maintenance management.

1. Material selection

Material is the basis for deciding the durability of steel structure. Choosing suitable steel and supporting materials can significantly improve the durability of the structure.

High-strength steel: The use of high-strength steel can reduce the self-weight of the structure and lower the stress level, thus improving the fatigue and corrosion resistance of the structure. For example, low alloy high strength steels such as Q345 and Q390 have better overall performance.

Weathering steel: Weathering steel is a kind of steel containing copper, phosphorus, chromium, nickel and other alloying elements, which is able to form a dense oxidation layer on the surface and effectively resist atmospheric corrosion. Weathering steel is commonly used in bridges, pylons and other open structures, which can reduce the use of anti-corrosion coatings and maintenance costs.

Stainless steel: For occasions where the corrosive environment is particularly harsh, such as chemical plants, marine platforms, etc., stainless steel or duplex stainless steel can be used. Stainless steel has excellent corrosion resistance, but the cost is higher, need to weigh the use of the actual situation.

Galvanised steel: Galvanised steel can effectively prevent corrosion of steel through surface galvanisation, and is commonly used in light steel structures and building envelope systems.

2. Design optimisation

Proper design can reduce stress concentration, corrosion risk and fatigue damage in steel structures, thus enhancing their durability.

Reducing stress concentration: Sharp corners, too small holes and uneven section changes should be avoided in the design, which will lead to stress concentration and increase the risk of structural fatigue and cracking. Stress concentration can be reduced by rounded corner transition and uniform section design.

Reasonable arrangement of drainage system: For open steel structures, drainage system should be considered during design to avoid water accumulation. Accumulated water can lead to localised corrosion of the steel, especially in the welds and connection parts.

Optimisation of connections: The way steel structures are connected has a significant impact on their durability. Welded connections are prone to residual stresses and welding defects, leading to stress corrosion cracking. Bolted and riveted connections reduce these problems, but require regular checking for loose bolts.

Consider fatigue design: For structures subjected to cyclic loading, such as bridges and pylons, fatigue should be fully considered in the design. Through reasonable fatigue design, the service life of the structure can be extended.

3. Protective measures

Protective measures of steel structure mainly include anticorrosion coating, cathodic protection, fireproof treatment, etc., which can effectively extend the service life of the structure.

Anti-corrosion coating: Anti-corrosion coating is a common method to prevent corrosion of steel structure. Common anti-corrosion coatings include epoxy zinc-rich primer, polyurethane top coat, fluorocarbon coating and so on. The choice of coating and construction quality directly affect the anti-corrosion effect. Surface treatment, such as sandblasting, acid washing, etc., should be carried out before coating to ensure the adhesion between the coating and the steel.

Cathodic protection: Cathodic protection is to inhibit corrosion by making the steel structure a cathode by means of applied current or sacrificial anode. Cathodic protection is commonly used in occasions where the corrosive environment is particularly harsh, such as marine platforms and underground pipelines.

Fireproof treatment: Steel structure will lose strength rapidly under high temperature, so it needs fireproof treatment. Common fire protection measures include spraying fireproof coating and cladding fireproof board. Fireproof coating can expand under high temperature and form a heat insulation layer to slow down the heating rate of steel.

4. Construction quality

Construction quality directly affects the durability of steel structure. Material quality, welding quality and painting quality should be strictly controlled during construction.

Welding quality control: welding is an important part of steel structure construction, and welding quality directly affects the strength and durability of the structure. Welding parameters should be strictly controlled during the welding process to avoid welding defects, such as porosity, slagging, cracks and so on. Non-destructive testing should be carried out after welding to ensure the quality of the weld.

Coating quality control: coating construction should be carried out in strict accordance with the process requirements to ensure the thickness, uniformity and adhesion of the coating. Surface treatment should be carried out before painting to remove rust, oil and other impurities. Coating test should be carried out after coating to ensure the anti-corrosion effect.

Installation precision control: the installation precision of steel structure directly affects its stress state and service life. The size, position and connection quality of components should be strictly controlled during installation to avoid stress concentration and deformation caused by installation errors.

5. Maintenance management

The durability of steel structure not only depends on the design and construction, but also on the later maintenance management. Regular inspection and maintenance can detect and deal with problems in time and prolong the service life of the structure.

Regular inspection: Regularly inspect the steel structure, focusing on corrosion, cracks, deformation and other problems. For corroded parts, timely repair and repainting should be carried out. For cracks, non-destructive testing should be carried out to assess the risk of expansion and reinforcement treatment should be carried out if necessary.

Cleaning and maintenance: Regularly clean the surface of the steel structure to remove accumulated dust, dirt, etc. to prevent the accumulation of corrosive media. For open structures, the drainage system should be cleaned regularly to avoid accumulation of water.

Record management: Establish a maintenance archive of the steel structure to record information on inspection, repair and replacement. Through data analysis, the health condition of the structure can be assessed and a reasonable maintenance plan can be formulated.

6. Environmental control

The environment in which a steel structure is located has a significant impact on its durability. The risk of corrosion and fatigue can be reduced by environmental control.

Control of humidity: High humidity environments accelerate corrosion of steel, especially in coastal and industrial areas. Through ventilation, dehumidification and other measures, environmental humidity can be reduced, reducing the risk of corrosion.

Controlling temperature: High and low temperature environments can affect the performance of steel. High temperatures can cause steel to soften and low temperatures can cause steel to become brittle. Temperature variations can be controlled through measures such as insulation and thermal insulation to reduce the impact on steel.

Conclusion

Enhancing the durability of steel structures is a systematic project involving material selection, design optimisation, protective measures, construction quality, maintenance management and other aspects. Through reasonable material selection, optimised design, effective protective measures, strict construction quality and scientific maintenance management, the durability of steel structure can be significantly improved, its service life can be extended and maintenance cost can be reduced. In the actual project, a reasonable durability enhancement programme should be formulated according to the specific use environment and requirements, taking various factors into consideration.