An assembly of structural elements capable of disassembly, capable of addition horizontally and vertically, capable of reduction in size horizontally and vertically, the entire structure accomplishing such purposes and objectives by the use of precast concrete elements, precast with wire tensioning bores...http://www.google.com/patents/US4059931?utm_source=gb-gplus-sharePatent US4059931 - Building framing system for post-tensioned modular building structures
