Page 343 - Trenchless Technology Piping Installation and Inspection
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Construction and Inspection for Cur ed-in-Place Pipe 299
Testing Issues
CIPP samples must be tested based on the ASTM guidelines previ-
ously mentioned. If testing results fall short of required flexural
modulus or thickness requirements, the required stiffness and actual
stiffness of the lining samples will be compared. After comparison, if
the average of actual stiffness is greater than 94 percent of the required
stiffness, the pipe will be accepted, but marked as noncompliant and
a deductive penalty proportional to the stiffness deficiency can be
assessed against the contractor. A change order will be issued for the
deductive penalty, in proportion to the deficiency, and the remaining
balance for the CIPP section will be paid to the contractor. If the aver-
age of actual stiffness for the CIPP section is less than 94 percent of the
required stiffness, the CIPP section will not be accepted and the con-
tractor will be required to install a second liner over the first liner to
compensate for the deficiency, at no extra cost to the project owner.
Full payment for the CIPP section will be issued to the contractor after
the second liner is properly installed and accepted. Assuming an
acceptable second liner is properly installed, no deductive penalty will
be imposed against the contractor.∗
To identify every defective condition and to suggest every correc-
tive measure or penalty is beyond scope of this book. This section is
only intended as a guide to aid in identifying physical conditions of
the installation, applying appropriate corrective measures, and assign-
ing deductive penalties for defective installations, which should all
be included in the bid and contract documents. This way the contrac-
tors know, before the bidding and start of the project, what expected
quality measures are and possible outcomes if these quality measures
are not met. This way, many quality problems, disputes, and potential
litigations may be avoided. The final decision for application, enforce-
ment, and final acceptance will ultimately be made by the owner’s
project/construction manager or the city engineer on a case by case
basis and as stipulated in the contract documents. Using codes pro-
vided in Table 7.8, Table 7.10 presents a summary of potential CIPP
defects, suggested acceptable tolerances, and possible repaired types
that may be required. Figure 7.8 illustrates potential CIPP defects.
∗The measured wall thickness has much more impact upon buckling resistance
than the flexural modulus. Its value adjusts the buckling resistance by its cube
power and is not directly proportional. Design engineers and project owners
should be cautioned that contractors may submit higher bids, or choose not
to submit a bid, if the contract contains unjustified quality requirements, low
tolerance expectations, and possibilities of penalties or rework. Including or
not including such language in the contract and justification of level of quality
required needs to be evaluated based on project owner’s needs, on the true
project hydraulic, structural, and performance requirements, and must be
evaluated in case by case basis using judgment of a knowledgeable professional
engineer.