Common methods for construction of large-span space structure

High-altitude in-situ assembly method

　　High-altitude in-situ assembly method refers to the direct assembly of rods and nodes in the structural design position, in order to ensure the safety of large-span space structure, the structure often need to set up temporary support to improve the structural stress performance, and then uninstall the temporary support after the structural installation is completed so that the structure reaches the design state, the setup of the temporary support structure makes the high-altitude in-situ assembly method has been very widely used.

        It is the basis for the construction and installation of complex large-span space structures, and other construction methods are evolved from this method. According to the different support, the overhead in-situ assembly method can be divided into full bracket installation method (full scaffolding method) and tire rack installation method. The all-support installation method is the method of using scaffolding to complete the total assembly of the structure in the air according to the curved shape and height of the structure. It applies to the height and span are not very large “hall” type structure, the advantages are construction flexibility, high recycling rate and easy to control the coordinates, the disadvantage is the use of scaffolding amount is relatively large, the construction process of insecurity factors increase. Compared with the latter tire rack installation method is not safe, but more economical. Tire rack installation method is based on the structural characteristics of the design of a similar scaffolding tire rack structure as a building support system to be installed. It is suitable for the large-span space “field” structure with high height, large span and self-weight, the advantage is that the tire frame structure has various forms, construction safety and accurate coordinates, the disadvantage is that the waste caused by the low recycling rate is serious.

Sliding in place method

　　The method of sliding in place refers to the installation method of sliding the partitioned bars to the design position through a specific track and then assembling them into a whole. This method is suitable for use in unfavorable areas of the construction site, the construction of the structure of the building plan is mostly a regular polygon or open stadium. The use of this method can shorten the construction period, so that the construction cycle is greatly shortened.But there are some difficulties, such as how to select the slip track and how to control the slip speed and other issues.

Overall lifting installation method　　

　　The overall lifting installation method is to use lifting equipment to lift the structure to the expected position and then install a method, mostly used in single or multi-layer mesh shell roof structure construction. The biggest advantage of this construction method is that it can save a lot of temporary support and the construction period is relatively short, while the corresponding construction difficulties are the grasp of the lifting point and the stress control of the lifted mesh shell structure. Integral lifting installation method is a supplement to the space in situ assembly method, generally used in combination with other methods.

Integral tensioning method

　　Integral tensioning method is a construction method using a certain number of hydraulic jacks to synchronize the tensioning of the cable to a reasonable elevation, especially suitable for the application of large-scale cable membrane structure installation. This construction method has high technical content, good science, convenient operation and easy control, so that the workload of workers and construction costs have been reduced significantly, so it is very reasonable and feasible to use this flexible construction method in the construction of cable membrane structure.

Mesh shell structure external expansion method 　　

　　Mesh shell structure external expansion method is one of the new construction techniques, the specific method is to assemble the middle part of the structure on the ground first, and then assemble part of the surrounding mesh shell after lifting it to a certain height, and then lift up the spliced mesh shell, and so on and so forth until the mesh shell structure is fully assembled. This construction method can save a lot of temporary support and easy to ensure the quality of construction, due to a large number of assembly is carried out on the ground, so the safety is also better. In view of the above advantages, the mesh shell structure external expansion method has received more and more attention in the construction of large-span space steel structure.

Suspension installation method

　　Suspension mounting method is to put together a small piece of unit on the ground first, and directly use lifting equipment to hoist this unit to the design position for assembling, which is suitable for small, not very complex structural form of space structure. Suspension installation method can reduce the number of temporary support to achieve the purpose of reducing the cost, but the safety is poor, the construction quality is not good to ensure that may produce large secondary stress. Because the stability of the installed members directly affects the installation of the later bars, the installed structural units are required to be geometrically invariant, have sufficient stiffness and basically no deformation relative to the design position, which requires the structure to be simulated and analyzed before the construction of the cantilevered installation method, and to do a good job of protective measures to eliminate the adverse effects.

        In the development history of human society, structures that can provide greater span and space are often the dreams and goals that people pursue, and the development of space structure largely reflects the development of human architectural history. The design of space structure should correctly and reasonably use different calculation theories and procedural methods to carry out accurate analysis, and at the same time, in the form design of space structure, we can’t only focus on the aesthetics, but also must pay attention to the rationality of the structural force and the cost of the project and other factors.