Abstract: An exoskeleton structure made up of a plurality of pairs of triangular units which are adjacent to each other and which are interconnected. Each triangular unit has a generally horizontal segment and a pair of upright diagonal segments connected to the respective ends of the respective horizontal segment. The segments of each structural unit are shell-like or transversely curved so that, when they mate with the segments of adjacent triangular units, the segments of the two units form frame elements having hollow interior spaces for receiving concrete which is directed into the hollow spaces after the structural units have been erected. The configuration of adjacent structural units is repeated throughout the entire extent of the structure so that the numerous triangular structural units form an exoskeleton structure having maximum strength and high resistance to lateral forces.