Abstract: A system for constructing the structural framework of a building or other structure of reinforced concrete is characterized by column and beam forms of sheet metal which remain in place as permanent parts of the framework after being filled with concrete. These forms are preferably factory-assembled, together with the necessary internal metal reinforcing skeletons, and shipped to the building site ready for erection of the column forms and interconnection thereof by the beam forms. Novel provisions are made, by means of walers and tensioned steel bands, for initially compressing opposed side walls of the forms to concave curvatures so that they are returned to essential flatness by the hydrostatic pressure of the fluid concrete.