Page 99 - Trenchless Technology Piping Installation and Inspection

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Gravity sewer

Solution to problem Renewal methods

Yes Yes
Structural Flow capacity Pipe Replace with Pipe bursting
problems? evaluation undersized? larger size pipe Open-cut method
No
Partially
Holes or No Semi-structural deteriorated
pipe section condition
liner lining methods
missing?
Partially
No Structural deteriorated
liner condition
Yes lining methods
Pipe bursting
Replace pipe
open-cut method

Hydraulic Yes Flow capacity Pipe Yes Replace with Pipe bursting
problems? evaluation undersized? larger size pipe open-cut method

Partially
No Semi-structural deteriorated
liner condition
No lining methods
Fully
Structural deteriorated
liner condition lining
methods
Joint Yes Repair joints Point source
leaks? repairs
No
Partially deteriorated Fully deteriorated Point source
No action condition lining methods condition lining methods repairs
necessary* 1. Cured-in-place pipe 1. Close-fit pipe 1. Chemical gel grouts,
2. Polyurea lining 2. Cured-in-place pipe cement-based grouts
3. Polyurethane lining 3. Modified sliplining 2. Epoxy resins, cement
4. Sliplining mortar
5. Thermoformed pipe 3. Internal seal
End 4. Point CIPP
*Continue to monitor based on your asset management
plan and pipe material and condition requirements.
FIGURE 2.15 Decision support system for gravity pipe renewal methods.