Rainwater gratings refer to the meshed structural plates used at the collection points of drainage pipelines on urban roads to prevent large debris. They are typically made of iron and usually feature a theft-proof design with a surrounding corner frame that can be securely fixed in concrete, followed by placing the grating into the frame. Rainwater gratings can be made from flat steel, twisted square steel pipes, or welded flat steel plates, and are now also available in high-strength plastics. If there is no suitable item number for installation, refer to the budget定额 description of the province. If there is no budget定额 description, use the item number for pre-buried iron components in construction budget定额 or the item number for steel prefabricated components manufacturing and installation.
The commonly used specifications for ductile iron gratings include:
450*750D400、450*750C250、450*750B125、400*700B250、400*700C125
400*600D400、400*600C250、400*600B125、400*500*30、400*500*20、350*500*40、300*500*30
300*500*20、350*500*30、250*500*30、250*500*25、250*500*20、200*400*20
Ductile Iron Grating Specifications: Extra Heavy Duty 400KN, Standard 250KN, Light 125KN; Bending Strength: Average 22MPa; Impact Resistance: Average 10J/m²; Compressive Strength: Average 25MPa; Tensile Strength: Average 10MPa; Ductility Strain Factor: Average 1000MPa; Water Absorption: 1%; Alkali Resistance: Sample remains corrosion-resistant and quality damage is 1% after immersion in 20% sulfuric acid solution for 48 hours.
In the installation of cast iron rain grates, the support points on both sides of the drainage channel must be level and firmly set. The steel reinforcement anchoring plates within the support frame must be deeply embedded in the concrete layer beneath the ground. It is recommended to design and construct using standard size dimensions. Also, select the appropriate type and specification of steel grating based on the total width and net weight of the cast iron rain grate, ensuring the dimensions match the installed grate. If flat steel is used, the orientation of the flat steel must align with the support points, and the length of the flat steel should be determined by the total width and spacing of the grate. Installation of cast iron rain grates must be carried out according to the required procedures and operational standards for both the safety of the construction team and the ease of construction, as well as to ensure that the installed grates can be投入使用 effectively and maintain their performance specifications.
