Answer:
179000 lb
Explanation:
The supports must be able to hold the weight of the tank and the contents. Since tanks are pressure tested with water, and the supports cannot fail during testing, we disregard the air and will consider the weight of water.
The specific weight of water is ρw = 62.4 lbf/ft^3
These tanks are thin walled because
D / t = 4.6 / 0.1 = 46 > 10
To calculate the volume of steel we can approximate it by multiplying the total surface area by the thickness:
A = 2 * π/4 * D^2 + π * D * h
The steel volume is:
V = A * t
The specific weight is
ρ = δ * g
ρs = 499 lbm/ft^3 * 1 lbf/lbm = 499 lbf/ft^3
The weight of the steel tank is:
Ws = ρs * V
Ws = ρs * A * t
Ws = ρs * (2 * π/4 * D^2 + π * D * h) * t
Ws = 499 * (π/2 * 4.6^2 + π * 4.6 * 50) * 0.1 = 37700 lb
The weight of water can be approximated with the volume of the tank:
Vw = π/4 * D^2 * h
Ww = ρw * π/4 * D^2 * h
Ww = 62.4 * π/4 * 4.6^2 * 50 = 51800 lb
Wt = Ws + Ww = 37700 + 51800 = 89500 lb
Assuming the support holds both tanks
2 * 89500 = 179000 lb
The support must be able to carry 179000 lb
