Abstract: A modular structure includes at least one modular unit comprising a structure base and a structure enclosure carried by the structure base. Each of the structure base and the structure enclosure comprises lightweight concrete providing a significantly improved structure over the currently used fabrication processes. The modular structure is fabricated utilizing tunnel fabrication processes, creating a unitary structure. The structure can be finished at a manufacturing location, then transported and installed at the desired location. Connector plate assemblies are molded into the structure for securing two adjacent modules. Adjacent modules can be oriented perpendicular, parallel, or any angle therebetween to each other.