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298 Cha pte r Se v e n
Condition of Pipe Design Parameters Liner Thickness
Partially deteriorated Groundwater level increases Increases
Ovality increases Increases
Fully deteriorated Groundwater level increases Increases
Soil cover increases Increases
Ovality increases Increases
Soil modulus increases Decreases
TABLE 7.9 Factors Affecting Design of CIPP
and collapse due to soil and live loads. The resin and the lining tube
make a composite material to determine the design thickness of the
CIPP. The types of resins have been described in Sec. 7.3. There are
generically two types of lining tubes––nonreinforced and reinforced
liners. The reinforced liners can be divided into fiberglass and carbon
fiber laminates.
Creep causes the CIPP to change shape, reducing its capability to
resist external pressures. Factors influencing the design of a liner
include physical properties of lining technology, and site and project
specific conditions as shown in Table 7.9. The pipe wall thickness
design is based on the anticipated effects on pipeline creep due to
external loads over a 50-year period as specified by ASTM F1216-09,
Eqs. X1.1 and X1.3. See Sec. 2.7 for sample CIPP design calculations.
Quality Issues
This section describes a suggested method for addressing CIPP qual-
ity issues. First, the project inspector will review CCTV post video
within two weeks of submittal by the contractor. In the event the
inspector finds that a corresponding tolerance level has been
exceeded, the inspector will flag the defect and handover the CCTV
post video to the project manager representing the owner or the city
engineer for secondary review. If the project manager agrees that the
defect is in excess of acceptable tolerance levels, he or she will deter-
mine acceptable remedies to correct the defects at no extra cost to the
project owner. If the contractor chooses not to correct the defects, a
deductive penalty can be imposed against the contractor. Once the
corrective work has been performed by the contractor to the satisfac-
tion of the project manager and the inspector, full payment for the
CIPP must be issued. In the event the contractor chooses to accept
the penalty deduction stipulated in the contract rather than to correct
the defect, a change order will be issued for the deduction and the
remaining balance for the subject CIPP installation will be paid to
the contractor.