If you don't have the skills then employ a designer with a proven record in silo design, don't rely on web sites.

The last thing you want is having to explain to your boss why there's 2500 te on the floor ■

The basic specificationis interesting as it indicates that the minimum inclination of the cone angle will be at least 76 degrees to the horizontal, which implies a Mass Flow construction to deal with a poor flow bulk condition of the ore. If the ore is not free flowing, the proportion of the cylindrical portion would seem barely adequate to give wall contact from a central fill, so the 'kick' pressure normally associated with mass flow will be neglible and the hoop stress in the bulk very low, particully given the velocity gradient that will be generated in the conical portion, at least relieving the hip joint of serious flow and wall pressure stresses.

As virtually the total weight of the bin and contents will be carried by the shell at the hip joint, I would have thought it easy to calculate the stress on the 34.5 metre circumfence of the welded joint and most likely find it to be high in relation to the bin wall thickness. In any case, the cost of a number of ribs would be trivial in this general construction.

However, it is presumed that this flow regime has been selected on the basis of material tests indicating the outlet size and wall angle necessary for reliable discharge, rather than a for a first-in, first-out requirement of an inert material. One may therefore query the basic design concept and whether an expanded flow construction would be more appropriate, with the transition at a diameter larger than the critical rathole size and using a self-clearing inclination on the upper cone section to reduce wear on the main storage region. ■

This is a big silo and carrying a heavy load on the hip. Support from the ring beam and connection to the cone requires a thorough structural analysis. Standard welding proceedure would apply to the joint, according to the thickness of plate adopted, but lap plates or vertical rib supplementary support can be given if required. Having in this case discounted additional stresses due to flow behaviour, the situation reduces to a structural engineering problem and I suggest that basic engineering design and workshop practice are beyond the scope of this forum as they are craft, rather than bulk technology issues. ■