Abstract: A tubular article with circumferential projections having radial or chordal corrugations. The chords have tooth-like formations or are parallel and directed vertically in underground installation. In the last case, the sides of the tube can be devoid of the corrugations, or have them radially or tooth-like. Furthermore, the projections can be skewed and alternating in the opposite directions. Also, the projections can have offset planes. Finally, in case of two corrugations, they are diametrically opposed in a single chordal direction and are represented by rings bent parallel to the applicable load which is adverse with thus prestressed projections.