CSA G40.21 Gr 300W plates API standard 650 flat-bottom oil storage tanks

In this project, an elemental area of tank wall used is constructed of ASTM A442 Grade 55 steel plate subjected to a meridional unit force, T1, of 4000 lbf/in.2 tension and a latitudinal unit force, T2, of 5060 lbf/in.2 compression. The meridional radius of curvature, R1, is 75 in., and the length of the normal from the surface to the axis of revolution, R2, is 300 in. The joints in the wall are of double-welded butt-joint construction with a tensile efficiency of 85%. A corrosion allowance of 1/16 in. is required.
The problem in this example is to graphically find the minimum thickness of tank wall required for the given conditions (see 5.10.3.3).
Solution: As determined from Table 5-1, the maximum allowable tensile stress value, Sts, for ASTM A442 Grade 55 steel plate in simple tension is 16,500 lbf/in.2. Since the compressive stress is latitudinal, the governing value of R in this situation is R1, or 75 in.

The API 650 specification provides guidelines for the API standard 650 flat-bottom oil storage tanks design, manufacturing, materials, installation and inspection of welded vertical and cylindrical tanks. Such containers must be on the ground and have a closed or open top.

Usually, the soil resistance of the foundation should be considered before the design and construction of API standard 650 flat-bottom oil storage tanks. The soil endurance in the API standard 650 flat-bottom oil storage tanks construction area plays a decisive role in the basic cost of the tank. In areas with high soil resistance, not only the cost of foundation treatment can be greatly reduced, but also the ratio of height to diameter of storage tank can be obtained. Therefore, the investment cost of the API standard 650 flat-bottom oil storage tanks can be greatly saved in the area with large soil resistance.