Main Technical Contents of Steel Structure
# Main Technical Contents of Steel Structure 1. **High-rise Steel Structure Technology** According to building height and design requirements, frame, braced frame, tube and mega-frame structures are adopted respectively. Members can be made of steel, rigid reinforced concrete or concrete-filled steel tube. Steel members are lightweight with good ductility; welded or rolled steel sections are suitable for super high-rise buildings. Rigid reinforced concrete members feature high stiffness and good fire resistance, suitable for medium and high-rise buildings or bottom structures. Concrete-filled steel tubes are easy to construct and are only used for columns. 2. **Space Steel Structure Technology** Space steel structures are characterized by light self-weight, high rigidity, attractive appearance and fast construction speed. Planar space trusses with spherical joints, multi-storey variable-section trusses and latticed shells using steel tubes as members are the most widely used space steel structures in China. They have the advantages of high spatial rigidity and low steel consumption, with complete design, construction and inspection specifications as well as comprehensive CAD systems. In addition to truss structures, long-span suspension structures and cable-membrane structures are also included in space structures. 3. **Light Steel Structure Technology** A modern structural system formed with light-colored steel sheets as wall and roof enclosures. The light steel system consists of thin-walled H-beams for wall beams and roof purlins (welded or rolled from steel plates over 5mm thick), flexible bracing systems made of round steel, and high-strength bolt connections. Column spacing can be 6m to 9m, span up to 30m or more, height up to more than ten meters, and light cranes can be installed. Steel consumption is **20–30 kg/m²**. Standardized design programs and specialized manufacturers are available, featuring high product quality, fast installation, light weight, low investment and year-round construction. It is suitable for various light industrial workshops. 4. **Steel-Concrete Composite Structure Technology** Steel-concrete composite structures refer to load-bearing beams and columns composed of steel sections or steel tubes combined with concrete, whose application has been expanding in recent years. Composite structures combine the advantages of steel and concrete: high overall strength, good rigidity and excellent seismic performance. With encased concrete, they provide better fire resistance and corrosion resistance. Steel consumption can generally be reduced by **15–20%**. Composite floor slabs and concrete-filled steel tube members also allow less or no formwork, enabling fast and convenient construction with great promotion potential. They are suitable for frame beams, columns and floor slabs of multi-storey or high-rise buildings under heavy loads, as well as columns and floor slabs of industrial buildings. 5. **High-strength Bolt Connection and Welding Technology** High-strength bolts transfer internal forces through friction and consist of bolts, nuts and washers. They feature simple construction, flexible disassembly, high bearing capacity, good fatigue resistance, self-locking performance and high safety. They have replaced riveting and partial welding, becoming the main connection method in steel structure fabrication and installation. For shop-fabricated steel members, automatic multi-wire submerged arc welding is used for thick plates; consumable guide electroslag welding is applied for diaphragms in box columns. On-site installation adopts semi-automatic welding, gas-shielded flux-cored wire welding and self-shielded flux-cored wire welding. 6. **Steel Structure Protection Technology** Steel structure protection includes fire protection, anti-corrosion and rust prevention. Generally, no additional rust prevention is required after fireproof coating application, but anti-corrosion treatment is still needed in buildings with corrosive gases. There are various domestic fireproof coatings, such as TN series, MC-10, etc. MC-10 series includes alkyd enamel, chlorinated rubber paint, fluororubber paint and chlorosulfonated paint. In construction, appropriate coatings and thicknesses shall be selected according to steel structure type, fire resistance rating and environmental requirements.