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. The members can be made of steel, composite 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. Composite reinforced concrete members feature high rigidity 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 lightweight, rigid, aesthetically pleasing, and constructed rapidly. 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 offer 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 used. 3. **Light Steel Structure Technology** A modern structural system formed by light-colored steel plates for wall and roof enclosure. The light steel system consists of thin-walled H-sections (over 5mm thick) for wall beams and roof purlins, round steel flexible bracing systems, 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 quality, fast installation, light weight, low investment, and year-round construction, 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. Their application has been expanding rapidly 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 in industrial buildings. 5. **High-Strength Bolt Connection and Welding Technology** High-strength bolts transfer stress 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 diaphragm plates 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, after fireproof coating application, no additional rust prevention is required, 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 includes alkyd enamel, chlorinated rubber paint, fluororubber paint, and chlorosulfonated paint. In construction, appropriate coatings and thicknesses shall be selected based on steel structure type, fire resistance rating, and environmental requirements.