Conical steel vessels, having an upper cylindrical section and supported by
a reinforced concrete shaft, are becoming widely used for water containmen
t in elevated tanks. However, the current codes of practice for water struc
tures in North America do not include any rational method for designing suc
h vessels. In this study, a simple and rational design procedure that consi
ders instability, yielding, large deformations, geometric imperfections, an
d residual stresses is developed for these hydrostatically loaded steel ves
sels. The procedure is based on a verified finite-element model and employs
a multiple-regression analysis to develop formulas that relate the maximum
stresses resulting from the hydrostatic pressure to geometric and thicknes
s parameters. The approach uses these formulas to permit the design of vari
able thickness liquid-filled conical tanks that are subjected to both hydro
static and snow load. Verification of the design procedure is carried out t
o prove that the procedure is accurate, economical, and conservative.