I want to make a circular floating pond on the ground with an area of 1000m square and a height of 1.4m to raise fish. My solution is to use sheet iron with a width of 1.4m to form a circle with a radius of about 17.8m, then line it with HDPE tarpaulin and pump water in. Please help me calculate the required thickness of iron plate to make the pond? Thank you!
The hydrostatic pressure of water is dependent on the height only. Assuming the water density at 1kg/l:
For simplicity, we measure the maximum hydrostatic pressure at the depth of 1.4m and ignore the additional strength from the plate mechanism working above this level.
The tensile force exerted on a centimeter-wide strip of the cylindrical tank is:
$$T=2*17.8*100cm/m*0.14=498.00kg/cm \ width$$ Assuming we use mild steel with a yield stress of 250mPa and a working strength of $$ \ 150 mPa=\pm 1500kg/cm^2$$ the total thickness, T, of the sheet is,
This divided by two will be the thickness of each side. $$3.3/2=1.65mm$$ So, we pick a round thickness that is better capable to be bolted or welded, say 2mm thick.