Create a 3D Prototype that can be folded

Job ID: 36133881

Budget: $30 – $250 USD

I need someone to design a board that can be folded. Board should hold the weight of around 15-20 Kilos when completely opened.
From the front the Board looks like a "U" shape, the base of the "U" should be twice in length as the sides (btw base is not completely round and not square - in between to allow enough space to fit something)
From the top, ratio of length to width is around 1:4

The main problem is folding it and when opened (be strong to hold some weight) without braking or bending