Design, fabrication and installation of bolted ball space frames

Bolted ball space frame structure because of its novel structure, reasonable force, light weight, low steel consumption and other advantages, China from the late 80’s a large number of emergence, every year about 80 ~ 1 million square meters increase. Such as large stadium bolted ball space frame, public venues bolted ball space frame, power plant bolted ball space frame, cement industry bolted ball space frame, warehousing and logistics bolted ball space frame, dry coal shed industrial bolted ball space frame, toll station gas station bolted ball space frame, exhibition centers, theaters, shopping malls, terminals, waiting halls, factories, warehouses, TV towers and other bolted ball node space frame. Domestic space frame structure is mainly divided into: welded ball node space frame and bolt ball node space frame two kinds. Bolted ball node rack has a large amount of processing in the factory and convenient on-site installation, which is suitable for the site of tight schedule, construction conditions, electricity constraints, complex shape of the rack, and difficult to locate the shaped structure of the rod. This paper focuses on the bolt ball node space frame.

Bolt ball net rack system is basically composed of rods, bolt balls, supporting supports and so on. According to the node form, it can be divided into cross truss system, quadrangular cone system, triangular cone system and so on. The support method is mostly fixed support. For large area, large span and special force or expansion requirements of the space frame structure can be used rubber bearing, sliding bearing, ball-hinge bearing and other support forms, in order to meet the structure’s own force stability, balanced, easy to release the internal force and other design requirements.

Bolt ball space frame structure is a kind of space structure formed by space frame rods and solid node steel balls connected by high strength bolts according to a certain space frame form. China began to introduce bolted ball space frame structure technology and products from abroad in 1978, through long-term practice, as a mature form of building structure, bolted ball space frame structure has been widely used in the construction industry at home and abroad. It is characterized by: light dead weight, large span, flexible design of plane shape, simple construction and positioning, and various installation methods. It is especially suitable for large curvature space structure system, such as barrel shell structure, spherical shell structure, and all kinds of architectural shapes.

Design drawings decomposition

A complete bolt ball node space frame design drawings should contain design description, space frame plan, space frame upper and lower chord and web arrangement, support and support details, rod material table, bolt ball material table, bolts, sockets, top wire material table, sealing plate, tapered head material table, bolt ball machining details (if there are other requirements to be added, such as hanging parts, ventilator room, etc.). First of all, review the space frame plan and foundation plan provided in the drawings to ensure that the position of the space frame support coincides with the foundation. Then review the rod material table provided in the space frame plan, mainly review the axial length of the space frame, and then review the welding length of the rod according to the axial length, and then review the length of the rod under the material. After everything is correct, then we can draw the workshop rod material table according to the rod material table.

space frame support design

Bolt ball space frame support bracket is generally Q235 steel, while the bolt ball for the 45 steel, due to the material differences between the two are large, the construction site support bracket installation are generally taken in the form of bolted connections, support bolts generally use M20 ordinary bolts can be. Support for the processing and installation methods can be divided into two. Support for a support bolt and support bracket welded, construction by rotating the support will be screwed into the bolt ball, support bracket plate must be made into a round; support for the support of two support bolts and support bracket is not welded, and in the top of the support bracket plate openings, the construction of the use of casing wrenches will be support bolts screwed into the bolt ball.

Bolted ball space frame structure installation construction program

There are various forms of bolted ball space frame structure installation, mainly including: scaffolding platform bulk installation; overhead bulk installation; ground assembly, overhead

The main forms are: scaffolding platform bulk assembly; overhead bulk assembly; ground assembly, overhead sliding assembly; ground assembly, lifting and pulling rod overall lifting; overhead platform assembly, sliding assembly, etc.

The quality of construction focuses on controlling the sagging deflection of the space frame and load control. Especially in the load control, it is strictly prohibited in the support structure.

In particular, in terms of load control, it is strictly prohibited to add loads arbitrarily before the supporting structure is fully in place and fixed, so as to avoid deformation of the space frame or even collapse accidents.