A prefabricated modular reinforced concrete building system includes panel assemblies for foundations, walls, decks, and roofs designed to be built out in a manufacturing facility, shipped to a job site, and filled with concrete. Panel assemblies incorporate a space frame to ensure structural integrity during shipping and during concrete fill. Space frames can include structural columns, rebar mats, spacers, straps, and skin panels. Panel assemblies may be manufactured to contain architectural interior/external finishes, windows/doors, and pre-installed utility distribution systems.

A prefabricated modular reinforced concrete building system includes panel assemblies for foundations, walls, decks, and roofs designed to be built out in a manufacturing facility, shipped to a job site, and filled with concrete. Panel assemblies incorporate a space frame to ensure structural integrity during shipping and during concrete fill. Space frames can include structural columns, rebar mats, spacers, straps, and skin panels. Panel assemblies may be manufactured to contain architectural interior/external finishes, windows/doors, and pre-installed utility distribution systems.

Ties, and related methods, for use in making insulating composite wall structures including first and second structural layers comprising a hardenable material and an insulating layer having a high thermal resistance disposed between the structural layers. The tie includes features that allow it to readily be either axially pushed through the insulating layer (e.g., by hand), or screwed through the insulating layer, (e.g., using a powered tool such as a drill). Thus, a tie of a single configuration is provided which is suitable for both methods of installation. The tie may include discontinuous helical ribs including limited prominence so as to not interfere with the ability to axially push the tie into the insulating layer by hand, yet, the ribs are prominent enough to catch the insulating layer as the tie is drilled in, helping it to screw into the insulating layer.

A composite structural building panel has a first concrete layer and a second concrete layer in spaced apart relationship with one another so as to receive an insulation layer spanning between the first concrete layer and the second concrete layer. A plurality of shear connectors are individually supported to extend through respective bores in the insulation layer between opposing first and second ends of the shear connector which are entirely embedded in the first and second concrete layers respectively. At least some of the shear connectors are oriented at an inclination to a normal axis of the insulating layer.

Methods, systems, and apparatus for constructing a wall panel and building are disclosed. The wall panel can include: fiber-reinforced concrete layers including concrete with interwoven fibrous materials; an insulation layer; and a connector. The insulation layer is sandwiched between the fiber-reinforced concrete layers, and the connector extends through the insulation layer and concrete layers to create composite action between the insulation layer and the concrete layers.