Platform plate steel grid has the characteristics of ruggedness, strong bearing capacity, large bending rigidity, saving steel, reducing platform self-weight, anti-slip, safety, easy construction, fast installation, etc. It has been widely used in petrochemical and other industries. In petrochemical enterprises, steel grid plates are mainly used in various steel-framed tower tanks, boilers, and other platform plates, as well as operating platform plates, floating roof tank tops and cooling tower walkway plates, pipe corridor walkway plates, power plant floor panels, and Steel inclined ladder step board and so on. The amount of platform steel grid plates is also very large in petrochemical enterprises. Taking steel frames as an example, the steel grid plate generally uses about 25% -35% of the steel in the frame. Therefore, choosing a platform steel grid that is economical and reasonable, saves steel, and meets the requirements of use has practical engineering significance.
I. Structural characteristics of steel grating
The material of the steel grid plate can be made of flat steel with a width of 20-70 mm and a thickness of 2-10 mm and twisted square steel (cross bar) made of 6-8 mm by drawing and twisting. The flat steel is placed side by side in parallel, and the twisted square steel is placed flat on the top of the flat steel. The pressure welding machine equipped with a high-power welding transformer and high pressure is used to firmly weld the two together. Flat steel mainly plays the role of bearing load, twisted square steel mainly plays the role of fixing flat steel and anti-skid. The products mainly implement the requirements of the People's Republic of China industry standard YB / 400l-2007. The material is ordinary carbon steel, and the products are generally 2 types. (That is, the distance between the crossbars is 50mm, 100mm), mainly three series (that is, the vertical bar spacing is 30, 40, 50mm) and more than 159 varieties. Can also be processed into any size and shape according to user requirements.
The shape of the steel grid plate can be flat or toothed. The surface state is mainly hot-dip galvanized. Manufacturers of steel gratings are generally responsible for platform steel grating design and field technical services. The platform steel grid is a factory prefabricated board, which can be welded to the beam during installation, and can also be connected with the beam or the board by the saddle clamp.
Design of Steel Grating Plate
1. Selection of platform steel grating:
The type of steel grid plate (including flat steel size, spacing, crossbar spacing, surface treatment, etc.) should be comprehensively considered with the support frame according to the design load requirements on the platform, and the optimal support span should be selected, and the platform steel should be minimized Grating specifications.
2. Selection of connection form:
Whether the connection of the girder steel grid and the beam is fixed by welding or saddle clamps should be comprehensively considered according to the requirements of use and the lateral stability of the supporting beam, as well as economically.
3.Reserved holes on the platform:
Because of the perforation of the process pipeline and the error in the installation of the pipeline, the steel grid plate needs to reserve holes. The size, location and processing requirements of the holes should be properly accounted for in the design.
4. Handling at frame beam and column connection nodes:
At the intersections of beams and columns at the joints of rigid nodes, the layout and elevation of steel gratings should be properly handled. At present, each manufacturer provides detailed instructions for selecting such products and relevant design and construction information, which is very convenient in application.
Ⅲ. Fabrication and Installation of Platform Steel Gratings
1. The production of platform steel gratings should meet the requirements of the People's Republic of China industry standard YB 4001-2007.
2. The installation of the supporting beam of the frame platform should be strictly on the same plane according to the design elevation to ensure the flatness requirements of the prefabricated steel grid.
3. Steel gratings should be hoisted in sequence, and welded to the supporting beam or fixed with saddle clamps in time.
4. In the installation and cutting holes, flat steel reinforcement should be used in the surrounding area.