ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
4.1 The fabrication of multi-branched space special-shaped joints in factories is complicated, the precision of component fabrication is high, the rods intersect, and the small fabrication deviation of any rod can cause large deviation of adjacent rods by enlarging the docking section. The tubular intersection node is programmed by computer, and the intersection line is cut by automatic cutting machine. Components are assembled by the method of tire film and ground sample line hammer, coordinates of total station are measured again, symmetrical welding with semi-automatic carbon dioxide gas shielding welding is adopted to effectively control welding deformation. Component fabrication error is controlled in the process of 3mm Yihan and deformation prevention measures are taken well. 4.2 Steel structural members of this project are installed on site in a multi-directional interlaced space state, and the faults are pulled each other. Limitation and restriction. According to the characteristics of the knot, the `in situ bulk loading process at high altitude'was adopted, and the temporary bracing frame was designed, checked, positioned and detailed drawings were compiled by using MIDATEEL and other software. The overall sequence of installation of the designed permissive components is not limited to the primary and secondary relationship of the force acting on the bar structure. According to the spatial position, the installation is carried out according to the principle of "from inside to outside, from low to high, layered and fragmented" [fig. 7].
In order to ensure the smooth development of hoisting construction, the simulation technology of measuring machine is used before construction to simulate component silking on computer, and the best hoisting sequence is selected to avoid the problems such as improper silk sequence causing subsequent components can not be installed. Choosing a reasonable structure of the frame is the basis of ensuring the safe and smooth installation of the cable. According to the characteristics of disorder and dense distribution in space, a frame structure combining independent and lattice structure is designed. The frame materials are H 400*400*13*21, H 300*300*10*15H 200*200*8*12 steel, and the connecting beams are made of D159*8 seamless tubes, all of which are made of Q235B. The H-section steel strong axis is oriented to the direction of loading, and crescent profiling tooling is set at the top. The combined tire frame solves the three difficult problems of bearing capacity, stability and anti-collision, and has high efficiency and safety. After the components are hoisted in place, the laser reflector and a small prism are used to capture the coordinates of the main pole and at least one bracket center to accurately locate the air attitude of each component and avoid accumulated errors.（ Fig. 8).
The straightness of the poles after assembling of multi-components is ensured by laying through lines on three sides of the pipe wall to meet the aesthetic requirements of the building. Components are joined by full welding, with a large amount of upside-up welding and limited welding space. Before welding, a highly suitable welding operation platform is set up to improve the worker's operating comfort. Because of the thin wall of the component, it is very important to control the welding quality to control the misalignment of the butt joint. In order to prevent welding distortion, two welders symmetrically weld the restraint plate at each joint position. In order to release the residual stress, the other end should be kept free.