A precast concrete wall structure and method for forming a wall structure are disclosed. A frame is positioned within a casting bed. The frame comprises first and second spaced apart metal tracks which are interconnected by a plurality of metal studs. The casting bed has a plurality of surfaces defining a generally rectangular interior area. A forming member is placed above the frame, the forming member comprising a layer of insulating material defining a plurality of integrally-formed rectangular protrusions extending in a parallel and spaced-apart relationship to one another to define a plurality of rectangular-shaped channels therebetween. Uncured concrete is placed within the casting bed and allowed to cure.