That has potential, though it may be hard to find a shape that's open enough to get concrete packed into, while still wrapping around the panels effectively (an

That has potential, though it may be hard to find a shape that's open enough to get concrete packed into, while still wrapping around the panels effectively (and you'd want to use a concrete with fibers mixed in to help with shear[1]). It might be possible to use epoxy resin instead. 1: https://en.wikipedia.org/wiki/Fiber-reinforced_concrete https://en.wikipedia.org/wiki/Fiber-reinforced_concrete