1. Mechanical design of a cylindrical storage tank
You are required to design a cylindrical storage tank with inner diameter 30 m, height 15
m to contain a liquid of density 1000 kg/m³. The tank is made out of carbon steel whose
density is 7850 kg/m³. The allowable stress is 165 N/mm², modulus of elasticity is 2 x 10?
N/mm² and the corrosion allowance is 1.5 mm. Take the joint efficiency as 0.85 in your
calculations.
A) Design the vessel shell considering the hydrostatic forces to act at different heights of
the shell. Assume 15 plates to be arranged in a circle to make the shell cross-section
with 2 mm gap between each plate for welding. Choose the appropriate length of the
plate from IS-1370 (Refer to Tables 1 and 2) given the plate width to be 2500 mm. Do
not go below a thickness of 8 mm for the top course. The answers are to be presented
as in the following tabulation.
Level or height (m) Plate thickness (mm) No. of plate layers
(8 marks)
B) The bottom of the storage vessel rests on a uniformly levelled surface. Find the
thickness of the bottom plate, sketch plate and the annular plate.
(2 marks)
