A pre-stressed concrete pipe is made by casting a concrete pipe inside a metal cylinder and then being pre-stressed by injecting solidifying compound under pressure into the boundary between the metal cylinder and concrete pipe, and includes a pair of end rings within the metal cylinder, each having a metal ring with an annular groove and an elastic band having a curved end to provide a rounded corner on the concrete pipe. After the solidifying compound is solidified, the concrete pipe retains the compression increasing its strength to withstand pressure, and moments caused by external loads. The pre-stressed concrete pipe further includes a bell ring mounted at one end and a spigot ring having a gasket ring at the other end. A bell clamp is mounted on the bell ring.

A gasket for concrete structures such as tunnel segments includes a gasket body having a bottom face configured to be positioned against a surface of an associated tunnel segment. First and second anchor members protrude from opposed side edges of the gasket adjacent the bottom face of the gasket. The anchor members are configured to attach the gasket to the tunnel segment during casting of a precast concrete member. The gasket body forms a groove in the concrete member and the anchor members form side channels in the groove. Should a defect be found in the original gasket, the gasket body can be removed from the groove of the concrete member relatively easily, even in the field, and a replacement gasket having corresponding anchor members can be snapped into the groove.

A cast-in-place gasket construction for concrete structures such as tunnel segments includes a gasket body having a bottom face configured to be positioned against a surface of an associated tunnel segment. First and second gasket portions of the construction extend in different directions and are connected to each other at a first joint. The gasket portions are made of an elastomeric material having a first durometer on the Shore A hardness scale. The joint comprises an elastomeric material having a second and lesser durometer on the Shore A hardness scale. A method for replacing a damaged frame-like gasket construction is also disclosed.

A gasket for concrete structures such as tunnel segments includes a gasket body having a bottom face configured to be positioned against a surface of an associated tunnel segment. First and second anchor members protrude from opposed side edges of the gasket adjacent the bottom face of the gasket. The anchor members are configured to attach the gasket to the tunnel segment during casting of a precast concrete member. The gasket body forms a groove in the concrete member and the anchor members form side channels in the groove. Should a defect be found in the original gasket, the gasket body can be removed from the groove of the concrete member relatively easily, even in the field, and a replacement gasket having corresponding anchor members can be snapped into the groove.

A cast-in-place gasket construction for concrete structures such as tunnel segments includes a gasket body having a bottom face configured to be positioned against a surface of an associated tunnel segment. First and second gasket portions of the construction extend in different directions and are connected to each other at a first joint. The gasket portions are made of an elastomeric material having a first durometer on the Shore A hardness scale. The joint comprises an elastomeric material having a second and lesser durometer on the Shore A hardness scale. A method for replacing a damaged frame-like gasket construction is also disclosed.

The invention relates to a protective element (20) for connecting to a concrete element (10) of a tunnel lining, to the concrete element (10) and to the method for producing the concrete element (10). It is an object of the invention to provide a protective element (20) for a tunnel lining, or the associated concrete element, which ensures that the protective casing of the tunnel lining is better safeguarded against corrosive gases or liquids. The solution of the invention provides that the protective element (20) is produced from an injection-moldable plastics material, that a protective portion (21, 22, 23) is connected in a single piece to a seal (30), wherein the connection is gas-tight and liquid-tight, that the protective portion (21, 22, 23) is connected in a single piece to a connecting element (24, 25, 26, 27, 28), and that the single-piece connection is produced by injection molding of the plastics material.