How is the grid structure installed?

III. Grid Installation 1. High-altitude Assembly Method: The method in which the members and joints (or small sub-units) of the grid are directly assembled into a whole at the designated high-altitude location is known as the high-altitude assembly method. The high-altitude bulk method is suitable for various types of grid structures with non-welded connections (ball bolt joints or high-strength bolt connections), and a cantilever construction method with few supports is recommended. Because grid structures welded together are constructed using the high-altitude bulk placement method, it is difficult to control the elevation and axis, and fire prevention measures must also be taken. 1) Process characteristics: The high-altitude bulk loading method is divided into two types: the full scaffold method (i.e., constructing a complete scaffold) and the cantilever method. The full-shelf method allows for the overall assembly of individual members and nodes on a shelf, or for assembly at height using a grid as a small assembly unit ； The cantilever method is used to save on supports by cantilingering part of the grid structure. The characteristic of the high-altitude bulk method is that the grid is assembled in one go at the designed elevation. Its advantage is that it can be assembled using simple lifting and transportation equipment, or even without any lifting equipment at all, making it suitable for areas such as mountainous regions with limited lifting capacity or difficult transportation conditions. Its disadvantages are the large amount of work required on-site and at heights, as well as the need for a substantial amount of scaffolding material. 2) Assembly brackets: The assembly brackets used in the high-altitude bulk loading method must be sturdy; bamboo or wooden materials should not be used. During design, calculations should be carried out to ensure the stability of each individual component as well as the overall structure, and the amount of settlement should also be estimated. The settlement amount should not be too large, and measures should be taken to allow for adjustments at any time during construction.

What is seen on site is that columns are erected first, then positioned using spot welding, and finally welded in place