Abstract: The subject matter of the invention is a scaffold tunnel for civil and industrial engineering applications, comprising a section bar secured to a fixed support and having mounted thereon, at predetermined spacings over the full length of the tunnel, a plurality of hinge mountings each composed of a bearing block and a hinged body. A metal scaffold secured to these hinge mountings is composed of hollow base section bars and hollow vault section bars of any suitable curvature adapted to have cover sheets of glass or a plastic material mounted thereon.The overall construction is completed by a plurality of suitable configured sealing gaskets, a corresponding plurality of finish section strips and a plurality of safety tensioners (FIG. 2 Tab. II).