Construction technology of general structure of space frame bolt ball

 1. Production of hollow steel balls and steel pipe rods

In order to ensure the installation and quality of the space frame and bolt ball processing, all hollow steel ball joints and steel pipe rods are processed centrally in the factory. The steel ball is made of tire film, and the raw material is No. 45 steel. Using lathe cutting, machining tolerance is: diameter deviation ±1mm, ball ellipticity deviation <1mm. The allowable deviation of the length of the steel pipe is ±1mm, the end face of the steel pipe must be perpendicular to the axis of the rod, the allowable deviation is 0.5%R(R is the radius of the steel pipe), the maximum bending of the steel pipe must not be greater than 1/1000 rod length.

2. Installation of steel space frame

Based on and guided by the theory of computer simulation, a detailed assembling scheme is made. According to the characteristics of the engineering structure and the layout of the construction site, scaffolding work platform is set up on the ground, planks are laid on the scaffold, and then the scaffolding work platform is assembled with mesh and bolt balls. The assembly of the mesh frame is carried out by air bulk method. According to the actual situation of the grid structure and the characteristics of left and right symmetry, in order to reduce the error accumulation of the grid in the assembly project, the assembly of the overall grid should start from the 8 axis and 9 axis of the starting unit, the vertical and horizontal axis of the starting unit should be assembled, and the size should be corrected at any time, and the starting unit grid can be expanded from the center to both sides after it is considered that the starting unit is correct. In the assembly process, the rod is hoisted into place by the scraper, and the assembly bolt is connected in the design position.

3. Grouping of starting units

Directly assemble a single bar and a single node into a network frame, and the position of each node should be measured and checked during the assembly process. After the grid of the starting unit is installed, conduct a self-check immediately to ensure that the bolts at all nodes are fastened properly. Position welding (3 points welded at each support) is performed to ensure that the grid does not displace during subsequent installation. Then the center of the starting unit is assembled in two directions at the same time.

(1) Assembly of basic units

The grid frame other than the starting unit is assembled by air bulk method, and the small unit is assembled first, and then the total grid frame is assembled, and the grid frame is divided into small units reasonably according to the actual situation when assembling, and finally the entire grid frame is formed. First, select a top string trigonal cone, and use a top string horizontal rod, 3 belly rods and a top string ball to spell out a unit cone that meets the design requirements. When assembling, all bolts at the spot of the unit cone section should be screwed in place. After the completion of this cone should be corrected, the diagonal error of the lower string rectangle should not exceed 1mm, in line with the above provisions is qualified, can carry out the next step of construction.