Tangential shear in API 650 anchored liquid-storage tanks

Generally, the snow load in the API 650 anchored liquid-storage tanks construction area should be considered before the design and construction of the tank. The snow load in the API 650 anchored liquid-storage tanks construction area has an impact on the tank roof design and operation, especially in the area with large snow load, the roof load of large storage tank with large diameter increases. Anti freezing, heat preservation and waterproof measures shall be taken for the additional facilities of storage tanks, such as pumps, breathing valves, flame arresters, detection instruments and thermal insulation layers.

The thickness of the API 650 anchored liquid-storage tanks annular bottom plates shall be in accordance with Table Q-4 (for steel or aluminum, as applicable). The thicknesses shown are minimums. The ring of annual plates shall have a circular outside circumference, but it may have a regular polygonal shape inside the tank shell with the number of sides equal to the number of annular plates. These pieces shall be butt-welded in accordance with Q.7.1.1, Item b. The plates of the first shell course shall be attached to the annular bottom plates by a weld as required by API 620 oil tank 5.9.5 except when a full-penetration weld is used or required (see Q.7.1.1). Butt-welds in annular plates shall be not closer than 12 in. from any vertical weld.

The calculated thickness of the above-mentioned wall panels required by the hydrostatic pressure is also It API 650 anchored liquid-storage tanks should be increased by the same ratio, unless special analysis is performed to determine the seismic overturning moment and the corresponding stress at the bottom of the wall of each layer of API 650 tank.