Manhole rehabilitation system
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.
1. A method for producing a manhole comprising the steps of:
establishing an excavation below a ground level;
exposing an external piping in the excavation;
providing a non-structural base structure in a base region of the excavation, the non-structural base structure having pipe openings;
removing a section of the external piping;
placing a channel pipe having opposing ends in the non-structural base structure, and attaching the opposing ends of the channel pipe to the external piping in place of the removed section of external piping, wherein the channel pipe passes through the pipe openings, and wherein the channel pipe has a section thereof removed so as to have an open channel therein forming a fluid conduit to the external piping;
filling at least a portion of the base region with a semi-fluid aggregate material; allowing the aggregate material to harden;
sealing at least one riser liner to an upper edge of the non-structural base structure; and
sealing a riser cap to an upper edge of the riser liner.
2. The method as recited in claim 1 wherein the channel pipe is formed of a polymer.
3. The method as recited in claim 1 wherein the open channel is open greater than 170° around a circumference of the channel pipe.
4. The method as recited in claim 1 wherein the step of filling includes the step of filling the non-structural base structure up to an upper edge of the channel pipe.
5. The method as recited in claim 1 wherein the non-structural base structure is formed of fiber reinforced plastic materials (FRP).
6. The method as recited in claim 1 wherein the at least one riser liner is formed of fiber reinforced plastic materials (FRP).
7. The method as recited in claim 1 , wherein the non-structural base structure is a base liner.
8. The method as recited in claim 1 , wherein the at least one riser liner is non-structural.
9. The method as recited in claim 1 , further comprising a step of placing a channel form/plug in the open channel of the channel pipe, substantially sealing the open channel from entry of debris.
10. The method as recited in claim 9 , wherein the channel form/plug is sacrificial.
11. The method as recited in claim 1 , further comprising a step of disposing a volume of aggregate fill exterior of the non-structural base structure and the at least one riser liner.