Abstract: A process for providing the surface of a film made from a weldable polymer material with projections. The projections are formed by particles which are applied, in particular sprayed, in the molten state onto the film surface. The welding factor is preferably significantly below 1.

Abstract: An arrangement for transmitting force in a predetermined direction from a sheet of weldable polymer material to a supporting surface, especially for fastening the sheet to the supporting surface. A fastening element anchored in the supporting surface extends through an orifice in the sheet and carries, on the side of the sheet facing away from the surface, a batten which extends parallel to the sheet transversely to the predetermined force direction. The batten is surrounded by an enveloping body which has been applied in molten form and is welded to the sheet.

Abstract: A process for laying a prepressed pipeline and pipe advantageously employed therein are described. Concrete pipe sections have an inner lining of a polymeric material anchored by flexible projections to the inner surface of the pipe. The thickness of the lining is increased at the ends of the pipe to form an elongated sealing surface and a stress absorbing region. A compression seal may thereby be employed. Stresses created by the seal are absorbed both by the thickened region and by a shoulder formed in the concrete wall of the pipe. In use, compression is maintained as the result of friction between the pipe well and the surrounding earth.

Abstract: A concrete pipe of the type employed, for example, in large sewers is described, having a concrete wall and an inner lining sheet of a polymeric or other plastic material anchored to the wall by a layer of fabric welded or otherwise firmly connected to the sheet. The fabric includes a plurality of preferably monofilament projections having a higher modulus of elasticity than the material of the sheet which projections extend into the inner wall of the concrete pipe and anchor the fabric and sheet thereto. A protective plastic ring and a covering strip positively support the sheet at the joint between two pipes.