Prefabrication requirements for roof and bottom plates of large vertical storage tank

Prefabrication requirements of large vertical storage tank roof:
The prefabrication of the tank roof shall be carried out in strict accordance with the drawings, and the spacing of welds after installation shall be paid attention to when lofting and blanking. The reinforcing rib shall be formed and inspected with arc template, and butt joint shall be adopted when single roof needs to be spliced. For the forming of single roof, the welding of reinforcing rib and roof shall be carried out on the mould. After forming, the arc template shall be used for inspection, and the gap shall not be greater than 10 mm.

Requirements for prefabrication of bottom plate of large vertical storage tank:
1. The diameter of tank bottom should be enlarged by 0.1% - 0.15% according to the design diameter.
2. The minimum dimension of edge plate along the radius of tank bottom shall not be less than 700mm.
3. The distance between any adjacent welds on the base plate shall not be less than 300 mm.