Selection and Application of Structural Steel Materials for Aircraft Maintenance Hangars​

 Aircraft maintenance hangars, as the core facilities for aircraft inspection and repair operations, must endure long-term exposure to large-span loads, extreme weather conditions, and complex operational environments. Consequently, stringent requirements are imposed on the strength, weather resistance, and stability of the structural steel materials employed. The judicious selection of suitable steel structural materials not only ensures the hangar's safe operation but also reduces construction and maintenance costs. Based on the functional requirements of different structural components within the hangar, commonly used steel structural materials can be categorised into three main types, each playing a critical role in hangar construction.

I. Primary Load-Bearing Structure: The Core Material Supporting the Hangar's ‘Skeleton’

The primary load-bearing structure forms the hangar's ‘skeleton’, bearing the hangar's own weight, aircraft parking loads, and external forces such as typhoons and snow accumulation. Consequently, material strength is the paramount consideration. Low-alloy high-strength structural steel (Q355 series) is the preferred choice for this component. boasting tensile strengths exceeding 355 MPa. This represents a 20-30% increase in strength over standard steel grades, enabling it to readily meet the load-bearing requirements of hangars with typical spans of 60-150 metres. Additionally, it possesses adequate weather resistance, resisting corrosion in humid environments and reducing long-term maintenance costs, making it the ideal material for core components such as columns and main girders.

For auxiliary load-bearing components like secondary beams and support purlins, carbon structural steel (Q235 series) offers greater advantages. Though its strength is slightly lower than the Q355 series, it provides superior cost-effectiveness and excellent workability. Its flexibility in cutting and welding allows adaptation to the hangar's complex structural connection requirements. This ensures structural stability while effectively controlling material costs, achieving a balance between safety and economy.

II. Roofing and Enclosure Structures: Outer Materials Balancing Protection and Practicality

Colour-coated steel sheets are a common choice for roofing and external wall cladding. Their polyester or fluorocarbon surface coatings resist ultraviolet radiation and rain erosion, offering a service life of 15-20 years. Weighing merely 10-15kg per square metre, they substantially reduce structural loads. Colours can be customised to project requirements, balancing functionality with aesthetic appeal.

To further enhance the stability of the outer structure, profiled steel sheets are frequently used in conjunction with colour-coated steel sheets. Through specialised forming processes, profiled steel sheets develop corrugated or trapezoidal structures, markedly increasing rigidity and effectively preventing deformation under load. Simultaneously, they serve as carriers for insulation and waterproofing layers, aiding in the construction of comprehensive thermal insulation and waterproofing systems for hangars. This creates a stable indoor environment conducive to aircraft maintenance operations.

III. Specialised Functional Materials: The Protective Barrier for Complex Environments

To address the unique environmental conditions of different regions, steel structural materials with specific functionalities must be selected to establish a robust protective barrier for hangars. For hangars situated in coastal, high-humidity, or industrially polluted zones, high-performance steel is the preferred choice for critical connecting components (such as gusset plates and bolts). Its surface naturally forms a dense oxide layer that prevents corrosion from penetrating deeper. With corrosion resistance 5-8 times greater than ordinary steel, it effectively withstands the erosion of coastal salt spray and industrial dust, thereby reducing maintenance frequency and costs.

Moreover, fire protection is paramount to hangar safety, with all exposed steel structures (such as main girders and columns) requiring fireproofing treatment. These materials utilise Q355 or Q235 steel as the base substrate, coated with an ultra-thin fireproof coating (3-5mm thick). Upon exposure to fire, the coating rapidly forms an expanding thermal barrier, preserving the steel's strength under high temperatures and ensuring no collapse occurs within three hours. This fully complies with the Grade 1 fire resistance rating standard for hangars, providing robust safeguards for personnel and equipment.

In summary, the selection of structural steel materials for aircraft maintenance hangars requires a comprehensive assessment of structural functionality, environmental characteristics, and cost requirements. From the load-bearing steel forming the ‘skeleton’ to the protective cladding materials shielding the exterior, and the functional materials addressing specialised environmental conditions, the synergistic application of diverse materials is essential to construct a safe, efficient, and economical aircraft maintenance space.