In the field of construction engineering, steel structures, with their efficient mechanical properties and flexible design capabilities, have become a key choice for modern architecture. For beginners, mastering the basic structural forms and selection logic of steel structures is the key to unlocking professional opportunities. Below, LWY will systematically explain five typical structures: light steel portal frames, steel frames, steel grid frames, cable-membrane structures, and tube trusses.
Core Structure and Load-Bearing Characteristics
The light steel portal steel structure consists of a portal frame, a purlin system (C/Z steel), and a support system, forming a planar load-bearing system. Its core advantage lies in its variable cross-section design, where beam and column cross-sections are optimized according to internal forces, achieving efficient material utilization. The use of lightweight corrugated steel sheets for roofs and walls reduces foundation loads by 40%-60% compared to concrete structures.
Typical Application Scenarios
It is suitable for industrial buildings (lightweight factories, warehouses, and logistics) and commercial facilities (exhibition halls and garages) with single spans of 20-30 meters and eaves heights of up to 10 meters. Construction takes only 4-8 weeks, and the cost is 20%-30% lower than concrete structures.
Structural Characteristics and System Advantages
A spatial load-bearing system composed of steel columns (H-shaped steel/circular steel tubes) and steel beams (H-shaped steel/composite beams) connected via rigid joints (fully welded/bolted/welded hybrid) can accommodate large column spacings exceeding 9 meters. By combining articulated joints with the support system, Steel Structure can flexibly adapt to different seismic fortification requirements.
Applicable Building Types
Multi-story Commercial: 5-15-story office buildings (such as SOHO buildings), with freely divisible floor plans to meet open office requirements.
Industrial: Heavy-duty workshops (such as machining workshops) capable of accommodating overhead cranes over 50 tons.
Seismic-Resistant Buildings: Its high ductility makes it the preferred structure for earthquake-prone areas.
Geometric Composition and Mechanical Advantages
A spatial load-bearing system composed of steel tubular members connected via spherical joints in a grid pattern achieves balanced bidirectional bending stiffness. The flat grid's thickness is approximately 1/10-1/15 of the span, while the curved grid's rise is 1/6-1/8 of the span. The overall steel structure consumes only 30-50 kg/㎡ of steel.
Important Applications
Sports Buildings: Stadiums (such as the Bird's Nest's exterior support structure) and swimming pools, covering ultra-large spans of 80-150 meters.
Transportation Hubs: Airport Terminals (such as the Beijing Daxing Airport's finger pier roof), achieving column-free, transparent spaces.
Industrial Plants: Aircraft Manufacturing Workshops, in conjunction with a suspended crane system.
System Structure and Load-Bearing Principle
Composed of high-strength steel cables, a tensioned membrane, and a supporting structure, the structure achieves a stable, hyperbolic shape through pre-tensioning. The membrane is only 0.5-1.5 mm thick and weighs less than 1 kg/㎡, yet boasts a tensile strength of 50-150 MPa. Combined with the cable net, it enables unsupported spans exceeding 200 meters.
Innovative Application Areas
Landscape Architecture: Stadium canopies, commercial plaza canopies
Eco-Architecture: Botanical garden greenhouses (Eden Project, UK), utilizing the high light transmittance (95%) of ETFE film to provide natural lighting
Temporary Architecture: Large exhibition halls (World Expo national pavilions), removable and reusable
Structural Features and Material Advantages
Circular steel tubes are connected through intersecting welded nodes or gusset plates to form a truss-type steel structure load-bearing system. The flexural stiffness of the steel tube section is 30%-50% higher than that of H-section steel, and the closed section offers excellent corrosion resistance, making it particularly suitable for humid/corrosive environments.
Diverse Application Scenarios
Industrial Plants: Heavy machinery plant roofs (spans 40-60 meters), capable of withstanding suspended loads exceeding 30 tons.
Bridge Engineering: Highway truss bridges (such as the Gutian Bridge in Wuhan), with spans up to 150 meters and a 60% weight reduction compared to concrete bridges.
Exhibition Buildings: Large-span exhibition halls (such as the Canton Fair Complex) achieve a clean, aesthetically pleasing design with rectangular tube trusses.
