Systems for reinforcement of structural elements such as piles, posts, pillars, and pipes are disclosed. The present invention features reinforced structural elements. The reinforced structural elements may include a sleeve structure positioned around a length of the structural element such that there is a chamber between the structural element and the sleeve structure. This chamber may be filled with concrete or another core filler material so as to reinforce the structural element. The sleeve structures of the present invention may be formed by the assembly of multiple staggered segmented layers of coupled reinforcing shells such as rigid, semi-rigid, or flexible fiber-reinforced shells.