I'm planning on building a circular cabinet where each shelf would have a different radius. All the shelves would be centered using a central pole running through their center. The cabinet will be surrounded by a frame to place the outer layer on it but it's not going to be that strong.
I'm wondering about how to support all of the shelves, what I thought of doing was placing spaced narrow boards (5cm width) in a semi circle layout or about ~210° (so as to not block the cabinet doors) between each pair of shelves. Each shelf (made of pine) would have to support about 15kg of weight. How many boards do you think would be enough? For example, if a 25cm radius shelf would have 13 boards (5cm width) spaced 8cm apart supporting it, would that be too many or too few?
The shelf would like this from above - the rectangles are the support boards and the bottom part is where the cabinet doors would go: