What are the installation methods for large-span steel structure workshop?
1. Overall jacking construction method
The dome structure has a long history of use, while the modern shell structure and space grid structure make full use of the three-dimensional characteristics of the dome structure, but the three-dimensionality of the dome has become an obstacle in the manufacture and installation of the structural system. The construction method is proposed to temporarily cancel the three-dimensional characteristics of the dome during the fabrication and installation process.
The core idea of the overall jacking construction method is to temporarily remove some rods and set a single-axis hinge in the structure to make the dome structure temporarily become a geometrically variable system during a period of construction, so that it can be folded during construction, and the structure is Assembly can be done on the ground or at a relatively low level. Not only the main body of the structure, but also the installation of indoor and outdoor decoration, electrical and mechanical equipment can be installed at a lower height, so that the installation work can be completed safely, quickly and economically. Then use blowing equipment to increase the air pressure in the dome or use lifting equipment such as jacks to lift it to a predetermined height and put it in place. When the structure reaches its final form, the temporarily removed rods during construction are installed in the corresponding positions to complete the installation of the entire structure. This method has significant advantages such as fast construction speed, low construction cost, safety and reliability, and easy guarantee of construction quality.
2. Overall upgrade construction method
At present, the overall lifting method and the overall jacking method are more and more widely used in the installation of grid frames and reticulated shell structures. However, these two methods are only an upward translation process during the lifting or jacking process of the structure, and there is no relative displacement between internal points, so these methods are only applicable to flat grid structures or relatively flat reticulated shell structures. It is not preferred for reticulated shells or grid structures with large curvature and high drop height. Professor Kawaguchi from Japan proposed a more practical "folding and unfolding" overall jacking construction method for the construction of double-curvature reticulated shell structures. This method is a new installation and construction method of reticulated shell structure. The basic idea is similar to the construction principle of "climbing dome". It is to remove some rods from the reticulated shell structure and fold it on the ground; The lifting equipment is raised to the design height; some of the removed rods are finally filled, and the whole construction process is a change process from mechanism to structure.
3. High-altitude cantilever assembly method with few brackets
For reticulated shell structures with large spans, high heights, and large coverage areas, if the traditional full-bracket installation method is adopted, the cost of the scaffolding alone will be high, and the disassembly and assembly of the scaffolding will also take a lot of time, and the construction period and cost will inevitably increase. The high-altitude cantilever assembly method with few brackets is to use the characteristics of each node of the reticulated shell structure to carry concentrated loads, and its own high rigidity and good stability. The installed part of the structure is used as the operating surface of the subsequent structure to be installed. To complete the installation of the structure. Using this method, in the early stage of construction, a small number of supports need to be erected according to the traditional installation method, and a 3-4 span reticulated shell structure should be installed to ensure that it has a certain rigidity and can bear subsequent construction loads; then the installed reticulated shell structure A support is suspended from the node, and subsequent structures are installed on it, and gradually expanded until the entire structure is installed. Compared with the traditional full-bracket installation method, this method can greatly reduce the amount of scaffolding, and at the same time, it can perform three-dimensional intersection operations on the ground, thereby greatly reducing construction costs and shortening the construction period. However, due to its relatively high-altitude operations, there are also certain problems Security risks.
4. Overall tension construction method
The integral tension construction method is suitable for flexible structures, especially cable-strut structures and cable-net structures.
For the construction of cable structures, the traditional construction method generally adopts the high-altitude bulk method, which requires the erection of a large number of temporary supports, and there are many high-altitude operations, which pose great safety hazards.
The overall tension construction method is to assemble the cable structure on the ground as a whole, and then use hydraulic jacks to lift the cable structure synchronously to connect with the surrounding rigid constraints, and then perform integral tension forming of the entire structure. This method avoids the potential safety hazards of high-altitude operations, and at the same time reduces the installation and disassembly of a large number of temporary supports, thereby saving time and reducing costs. More importantly, the displacement and deformation of components can be accurately and effectively controlled during the entire lifting process. and stress state.
Principles for selecting installation and construction methods for large-span steel structure workshops
For the installation and construction method of the new long-span steel structure factory building, although the technology is advanced, it is mainly suitable for some specific structural forms. Such as "climbing dome method", "folding and unfolding method" and "high-altitude cantilever method with few supports", which are mainly suitable for large-scale grid and reticulated shell structures. The "folding and unfolding" construction method is more suitable for the lifting process of folding and unfolding curved surface structures with large curvature. The "integral tension method" is suitable for cable structures.
To sum up, the choice of installation and construction method for a large-span steel structure workshop should be based on the specific conditions of the project, combined with the actual situation on the site, the conditions of the lifting equipment and the characteristics of the structural system, and choose the best solution according to local conditions.
