If you are asking this type of question on a forum and expecting to get a specific answer without any detailed information. I would not want to be using you as my designer. You are best to hire a consultant who specializes in that field and work with him/her. ■

Before posting a request such as this you ought to know something about what you are asking.

Pile cap design is not your full quest. If there is a radial stacker it will probably incorporate a central draw down and take out tunnel so it is very unlikely that a 3 point pile cap will go anywhere near satisfying the civil requirements. Is the pile covered? If so then the ring beam will also have to sustain the seismic load. Also be aware that during a seismic event the first thing to become disturbed will be the overhead conveyor connection with the centre column. The piling is rather secondary eg. consider that during a seismic disturbance in a silo situation the ensiled material slams into the silo wall, not the other way round as an earlier thread poster stated. Why is that? Simply because the wall is fairly rigidly fixed to the ground whereas the ensilement is comparitively fluid and will lag. So you need a high level connection that will hold up the central colunm, not the other way round.

As Gary implies, you are out of your depth and working beyond the limits of your competence: something that professional engineers are legally forbidden to undertake. Although the design stages are many and varied there is an underlying requirement to incorporate standards which establish the ground conditions; identify the seismic area and its known behaviour; quantify the load spectrum of the machine and associated structures and only then perform a seismic study based on the local behaviour.

If anybody provided you with a specimen calculation to follow then he or she might have to answer to a tribunal if the building fell down and his or her name was quoted. Bad enough if they get paid for it, and are insured, but even worse if you got the info for nowt. ■