What are the characteristics of several space frame structures?

 The space frame structure is one of the new structures required for the development of today's society. Since the 1960s, China has conducted in-depth research on the space frame structure and has achieved good results in practical applications. It has also allowed China-made space frame structures to be exported overseas. In recent years, the rapid development of electronic computing technology has solved the calculation problem of the high-level statically indeterminate structure of the space frame structure, making the space frame structure have an unexpected leap in terms of type and practical engineering application. The space frame structure will usher in greater breakthroughs and create more miracles.

The space frame structure includes double-layer plate-type space frame structure, single-layer and double-layer shell-type space frame structure. The members of the plate type space frame and the double shell type space frames are divided into upper chord, lower chord and web members, which are mainly subjected to tension and pressure. The nodes of single-layer shell-type space frames are generally assumed to be rigidly connected and should be calculated according to the finite element method of rigid-connected rod systems; double-shell space frames can be calculated according to the finite element method of hinged rod systems. Both single-layer and double-layer shell space frames can also use the pseudo-shell method to simplify calculations.

The rods of the single-layer shell-type space frame does not only bear the tensile force and pressure, but also bear the bending moment and shear force. At present, most of China's space frame structure adopts plate type space frame structure. This structure is a kind of spatial space frame structure. The so-called "spatial structure" is relative to the "planar structure", which has the characteristics of a three-dimensional effect. Since the advent of the space structure, it has been welcomed by people for its efficient stress performance, novel and beautiful form and quick and convenient construction. The spatial structure can also be seen as the expansion and deepening of the planar structure. The space frame structure is a spatial rod system, which mainly bear axial force, and the cross-sectional size is relatively small. Space frames are used in stadiums, convention and exhibition centers, cultural facilities, transportation hubs and even industrial plants that require large spans and large spaces, and you can see the traces of spatial structures. The advantages of the space frame structures are small amount of steel, good integrity, quick production and installation, and can be used in complex plane forms. Suitable for structures with various spans, especially for complex plane shapes. The intersecting rods in these spaces support each other and combine the force-bearing rods with the supporting system organically, so the materials are economical.

Space frames frames are mainly used in large and medium-span public buildings, such as stadiums, hangars, clubs, exhibition halls, and waiting halls. Small and medium-sized industrial plants have also begun to be promoted and applied. The larger the span, the more significant the advantages and economic effects of adopting this structure. Space frame structure -The plate type space frame structure is divided into three types according to the form of composition: the first type is composed of a plane truss system, with two-way orthogonal orthographic space frame, two-way orthogonal diagonal space frame, and two-way oblique cross. There are four types of space frame racks and three-way space frames; the second type is composed of quadrangular pyramid units, including positive quadrangular pyramid space frames, positive evacuated quadrangular pyramid space frames, oblique quadrangular pyramid space frames, and checkerboard quadrangular pyramid space frames. There are five types of racks, and star-shaped quadrangular pyramid space frame. The third type is composed of triangular pyramid units, and has three forms: triangular pyramid space frame, evacuated triangular pyramid space frame and honeycomb triangular pyramid space frame. Shell type space frame structure is divided into cylindrical shell type space frame, spherical shell type space frame and hyperbolic parabolic surface shell type space frame according to the shell surface form. The space frame structure is divided into steel space frames, reinforced concrete space frames, and combined space frames composed of steel and reinforced concrete according to the materials used, of which steel space frames are more commonly used.

According to different shapes, the space frame structure can be divided into double-layer plate-type space frame structure, single-layer and double-layer shell-type space frame structure. The members of the plate type space frame and the double-layer shell type space frame are divided into upper chord, lower chord and web members, which mainly bear tension and pressure; the members of the single-layer shell type space frame, in addition to bear the tension and pressure, also bear Bending moment and shear force. At present, most of China's space frame structure adopts plate type space frame structure.

According to actual use: the steel structure is a spatial structure formed by connecting multiple rods in a certain space frame form through nodes. It has the advantages of space stress, light weight, high rigidity, and good seismic performance; it can be used as a house for buildings such as stadiums, theaters, exhibition halls, waiting halls, stadium stands, hangars, two-way large-pillar space frame structures, and workshops covers.

The space frame has the characteristics of light weight, high strength, good overall rigidity, and strong deformability. At present, the demand for the space frame is also increasing. The structural roof is composed of cold-formed thin-walled steel components, and the steel frame is made of super anti-corrosion and high-strength cold. Manufacture of rolled galvanized sheet, effectively avoiding the influence of corrosion of steel sheet during construction and use, and increasing the service life of light steel components. The structural life can be up to 50 years.

The thermal insulation material used in the steel structure space frame is mainly glass fiber cotton, which has a good thermal insulation effect. The use of thermal insulation boards on the outer wall effectively avoids the "cold bridge" phenomenon of the wall and achieves a better thermal insulation effect. The thermal resistance of R15 insulation wool with a thickness of about 100mm can be equivalent to that of a brick wall with a thickness of 1m. The assembly of the space frame structure is generally carried out on site. Before leaving the factory, the bolted spherical joint space frame should be pre-assembled to check the size and deviation of the parts.

The assembling of the space frame should be assembled according to the different construction and installation methods, using separate assembly, quick assembly or overall assembly. The space frame assembly should be carried out on a flat rigid platform. When assembling the space frame of welded hollow sphere nodes, the assembly sequence should be correctly selected to reduce welding deformation and welding stress. According to most domestic engineering experience, the assembly and welding sequence should develop from the middle to the two sides or all around, and it is best to go from the middle to the two sides.  when the space frame is assembled forward, the ends and the front can be freely contracted. After welding a section of steel structure products, the size and geometry can be checked once, so that the welder can make adjustments during the next tack welding. Avoid forming a closed circle during the assembling of the space frame. If welding is performed in the closed circle, the welding stress will be very large.