A manhole assembly including a base, riser, and cap. The base having an upper surface forming a bench, a bottom surface, and a radially outward surface with penetrations there through; and a radial spigot in the radially outward upper edge of the base. The base having a corrosive-resistant layer covering the channels, bench, and radial spigot. Also disclosed is a riser comprised of a corrosive-resistant polymer pipe having a radially outward surface, an inner surface and a bottom surface in contact with, supported by, and sealed to the radial spigot. The cap having a radial spigot, and access hole; the radial spigot in the radially outward bottom edge of the cap resting upon and sealed to an upper edge of the riser. The radially outward surface of the cap and base are aligned with the radially outward surface of the riser.

A manhole rehabilitation system where in one example an existing cross-pipe is exposed and a manhole base and riser are cast around and above the existing cross pipe to form a manhole. In one example an FRP base liner and FRP riser liner are placed before casting in place. In one example casting is made of an aggregate. In one example, a collar and manhole cap rest upon the casting, and are supported thereby such that the liner need not be structural. In one example an existing pipe or manhole forms the outer surface of the casting. In one example shoring is placed and used as the outer surface of the casting.

A prefabricated composite concrete element for use in a corrosive sewer environment. The concrete element has a hollow reinforced cast concrete portion with at least one end having connection details, a premolded corrosion resistant inner plastic liner. The plastic liner lines an interior of the hollow concrete element and the connection details to provide abutting liner faces in an assembled joint to limit exposure through said joint of said concrete portion to corrosive materials arising in said sewer environment. At least two prefabricated composite concrete elements may be assembled end to end at a joint to form a concrete sewer system. Also disclosed are a method of prefabricating such a composite concrete element.

A manhole base assembly and a method for making the same employ a non-cylindrical, low-volume concrete base that is fully lined to protect the concrete against chemical and physical attack while in service. This lined concrete manhole base assembly may be readily produced using a modular manhole form assembly which can be configured for a wide variety of geometrical configurations compatible with, e.g., varying pipe angles, elevations and sizes. The form assembly is configurable to provide any desired angle and elevation for the pipe apertures to interface with various underground systems, and can be formed on-site to facilitate compatibility with existing structures. The assembly provides for flexible, modular construction of a wide variety of lined manhole base assemblies at minimal cost, reduced concrete consumption and reduced operational complexity. The modular nature of the production form assembly also facilitates reduced inventory requirements when various manhole base assembly geometries are needed.

A riser section having a generally tapered, e.g., frustoconical wall, the riser section having a first connector assembly at one end of the riser section and a second connector assembly at the other end of the riser section.

A prefabricated composite concrete element for use in a corrosive sewer environment. The concrete element has a hollow reinforced cast concrete portion with at least one end having connection details, a premolded corrosion resistant inner plastic liner. The plastic liner lines an interior of the hollow concrete element and the connection details to provide abutting liner faces in an assembled joint to limit exposure through said joint of said concrete portion to corrosive materials arising in said sewer environment. At least two prefabricated composite concrete elements may be assembled end to end at a joint to form a concrete sewer system. Also disclosed are a method of prefabricating such a composite concrete element.

The present invention is a method for rehabilitating, repairing, and replacing manholes and connected sewer lines. In some embodiments, a compressed liner is inserted through the manhole access hole or the connected sewer lines. Prior to insertion, the liner may be cut and/or folded to be compressed to a size that can fit through the manhole opening or the sewer lines. Once inserted in the manhole or sewer lines, the liner should be expanded, and if necessary, bonded together with a resin along the separation line. Next, a bonding material may be injected between the liner and a surface of the manhole or sewer line to seal any cracks or fissures in the brick or concrete wall and to seal the liner against the existing manhole or sewer line to improve structural integrity and longevity. A new corbel may then be installed and bonded to the liner.

A manhole rehabilitation system where in one example an existing cross-pipe is exposed and a manhole base and riser are cast around and above the existing cross pipe to form a manhole. In one example an FRP base liner and FRP riser liner are placed before casting in place. In one example casting is made of an aggregate. In one example, a collar and manhole cap rest upon the casting, and are supported thereby such that the liner need not be structural. In one example an existing pipe or manhole forms the outer surface of the casting. In one example shoring is placed and used as the outer surface of the casting.

A riser section having a generally tapered, e.g., frustoconical wall, the riser section having a first connector assembly at one end of the riser section and a second connector assembly at the other end of the riser section.

A manhole rehabilitation system where in one example an existing cross-pipe is exposed and a manhole base and riser are cast around and above the existing cross pipe to form a manhole. In one example an FRP base liner and FRP riser liner are placed before casting in place. In one example casting is made of an aggregate. In one example, a collar and manhole cap rest upon the casting, and are supported thereby such that the liner need not be structural. In one example an existing pipe or manhole forms the outer surface of the casting. In one example shoring is placed and used as the outer surface of the casting.