Definition of large spans by steel structures

Steel structures with a lateral span of 60 meters, concrete with a span of 30m or more, and frame structures with a span of 18m or more are large-span structures.

The shape of the large-span space structure is space-like and has three-dimensional force characteristics at the same time, with the shortest route of load transfer, uniform force and other characteristics.

It is mainly used in civil buildings such as theaters, stadiums, exhibition halls, assembly halls, airports and other large public buildings. In industrial buildings, it is mainly used in aircraft assembly workshops, hangars and other large-span plants.

Large-span space structure is often an important symbol to measure the level of construction technology in a country or region, and its structural form mainly includes five major space structures such as space frame structure, net shell structure, suspension structure, membrane structure, thin shell structure and various types of combined space structure.

1、space frame

By a number of rods in accordance with a certain regular geometry, through the nodes connected to the space structure of the double or multi-layer flat plate-shaped space frame, which is usually made of steel pipe or section steel materials.

2、Mesh shell structure

It is a curved mesh structure with single-layer mesh shell and double-layer mesh shell. Mesh shell material mainly has steel mesh shell, wood mesh shell, reinforced concrete mesh shell.

3、Space truss structure

(1) According to its shape, it can be divided into: parallel chord truss, folded chord truss and triangular truss.

(2) According to the horizontal thrust of truss: beam truss without thrust, arch truss with thrust.

4、Membrane Structure

It takes soft fabric with excellent performance as material, supports the membrane surface by air pressure inside the membrane, or utilizes flexible steel cable or rigid supporting structure to make the membrane produce a certain pre-tension, thus forming a structural system with a certain stiffness and able to cover a large space.

5、Suspension structure

It is to take the cable which can be pulled as the basic load-bearing member, and arrange the cable according to a certain rule. Suspension roof structure usually consists of three parts: suspension system, roof system and support system. Most of the steel cables used in the suspension structure are made of parallel steel wire bundles composed of high-strength steel wires, steel strands or steel cables, etc. Round steel, steel profiles, steel strips or steel plates and other materials can also be used.