You are asking for a structural design for an apparently perfectly normal conveying situation. Apart from the pneumatic conveying forum nobody designs for free. Advice on problems yes, free detail structural design no.

Structural analysis programs and textbooks are available through normal outlets and public libraries etc. Try them. There you will find instructions regarding wind loads and live loads etc.

Incidentally you have left out the take up criteria which would undoubtedly form the basis of a follow up question. That's what normally happens with this sort of thread.

Others would tell you that your question glosses over the issues of floor spillage loads and start up dynamics to name a few.

The underlying question is "What kind of management gives such a task to such inexperienced players?"■