In recent years, the construction of space steel structure has developed vigorously in our country, from the general steel structure to high-rise and super high-rise steel structure, with large span of space steel structure -- grid, mesh shell, suspension cable structure, tensile film structure, prestressed steel structure, steel-concrete combination structure, light steel structure and so on.
Steel structure installation, is a more complex comprehensive technology, its content is more, the range is wider, different structure types, different processing and production programs, the final installation method is completely different. How to scientifically select the safe, reliable and economical optimal installation scheme according to various factors is an important embodiment of the installation level of steel structure.
Space steel construction preparation
⑴ Technical preparation: To develop the installation technical plan, the single-layer steel structure project should adopt the installation method, the roof system should adopt the comprehensive installation method. Multistory steel structure engineering generally adopts comprehensive installation method.
(2) Preparation of construction machines and materials: including hoisting machinery, various auxiliary construction machines and tools, steel components, various welding materials and fasteners, etc.
⑶ Column base inspection: column leveling and elevation control, check the axis and spring the installation alignment line, check the axis position, size and quality of the anchor bolt.
⑷ Component cleaning: clean the steel column and other first lifting components, numbering and good installation line.
Steel structure installation control points
First, installation precision control
Measurement and control should be carried out in the installation of complex space steel structure. Because the measurement and control of steel structure construction is a part of the construction technology, the rationality and advanced nature of the engineering construction scheme are analyzed from a large number of measurement and control data information and the results are reacted and confirmed. For the large-span steel structure, because in the construction process, the deformation and stress state of the structure and after forming are very different, so it is necessary to use a variety of support tire frame to ensure the accuracy of the structure.
Two, disassembly control
Due to the characteristics of large-span steel structure, such as large gross tonnage of unloading, wide distribution of unloading points, large force of single unloading, and heavy load of unloading calculation and analysis, if the release of supporting force is unreasonable, the structure will be damaged or the scaffold will gradually become unstable. Therefore, when unloading steel structure, it is necessary to take system conversion scheme as the principle, structural calculation and analysis as the basis, structural safety as the purpose, deformation coordination as the core, real-time monitoring as the guarantee, in strict accordance with the requirements of equiratio method and equidistance method for unloading.
Iii. Hoisting scheme
When hoisting large-span steel beams, if reasonable lifting point calculation is not carried out, the traditional two-point hoisting is still selected. Due to the long structure of steel beams, the large distance between lifting points, the dead weight and variable load, the steel beams and cables are subjected to great axial force, and the lateral bending of steel beams is easy to occur, or even more serious deformation. The construction site of long-span steel structure should strengthen the management, increase the professional knowledge training of workers, so that they have a more concrete understanding of the mechanical characteristics of components and hoisting knowledge. At the same time, strengthen the construction organization design to carry on reasonable demonstration of hoisting scheme, so as to choose a more reasonable hoisting scheme.
Iv. Installation sequence
Because the installation sequence of long-span steel structure is high, if the installation sequence is not properly considered, the steel components do not meet the needs of lifting, it may affect the safety of the structure. During the construction organization and design, the installation sequence should be arranged reasonably, and the processing, component transportation and site installation should be coordinated in a unified manner, which should be strictly implemented during the construction process. In addition to carefully formulating the installation sequence suitable for the project, an experienced construction team should also be selected for installation to avoid quality hazards.
Key points of steel structure coating technology
First, rust removal before coating
(1) Steel surface should be derusting treatment, after chemical derusting steel surface should reveal metallic luster.
(2) The surface of the treated steel should be free from welding slag, welding scar, dust, oil, water and burr.
(3) No mistake coating, leakage coating, coating should not fall off and return rust phenomenon.
(1) The rust removal grade of the steel surface before coating shall meet the requirements of the design and the current national specifications.
(2) The brushing should be uniform, no obvious wrinkle, fall, bubbles and other phenomena, good adhesion, color separation line is clear and neat
Of course, there are many other details that need to be paid attention to in the installation and construction process of space steel structure, including a variety of safety and civilized construction precautions. Construction within the safety regulations is the responsibility and obligation of each staff to learn and strictly abide by.
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