Page 237 - Trenchless Technology Piping Installation and Inspection

Pr oject Considerations for Horizontal Dir ectional Drilling 201

feasible. However, a day-work contract requires much greater over-
sight by the owner than a typical lump sum or turnkey contract.
Although a cost-plus contract may not specify contractor perfor-
mance in terms of installation details, standards of contractor per-
formance are required and should be clearly defined. The required
performance primarily involves the provision of equipment of a
specified capacity. The components of equipment should be listed as
well as conditions with respect to downtime, maintenance, crews,
fueling, etc. In additional, items in the scope of work which can be
contracted on a lump-sum basis, such as mobilization and site prepa-
ration, should be broken out, priced on a lump-sum basis, and gov-
erned by appropriate performance specifications.

Unit Price (Footage) Contracts
For a unit price contract, the owner estimates the number of units
included for each element (activity) of work, such as linear feet of
installed product pipe. In addition, the contract may include ancillary
work such as tie-ins, pit excavation, mobilization and demobilization,
or traffic control––typically provided on a lump-sum basis, as well as
other items the owner or engineer may require, to be listed separately.
The contractor determines the unit price bid for the various items
in the contract, as listed by the owner. The contractor should include
overhead and profit within the unit prices, and reflect all the costs for
each element of work, such as utility locating and potholing. It should
be noted that actual unit price portion may change from estimated
values based on the quantity of work realigned in the field.
The unit price contracting method is most commonly used for
installation of pipelines using Mini- and Midi-HDD systems.

5.3.8 Inspection and Construction Monitoring
The primary objectives of an inspector involved in construction mon-
itoring on an HDD installation are to assist in the interpretation of the
contract documents and to verify conformance, or nonconformance,
by the drilling contractor. In the conduct of this task, it is important
that the inspector document his or her observations and actions.
Should a question or dispute arise after the installation is complete,
the inspector’s notes may provide the only source of confirming data
and information. Since a drilled installation is typically buried with
deep cover, often under an inaccessible obstacle, its installed condi-
tion cannot readily be confirmed by visual examination.

Directional Performance
The inspector should be concerned with directional drilling perfor-
mance with respect to two basic measures: position and curvature.
The contractor must install the pipeline such that the drilled length
and depth of cover specified by the contract are satisfied. Further-
more, the contractor must not provide a path such that the pipeline
will be damaged or overstressed during installation or subsequent