Page 423 - Trenchless Technology Piping Installation and Inspection

Planning and Safety Considerations for Trenchless Installation Methods 373

Illustrative examples are provided in the guidelines document. The
baselines establish a contractual statement of the conditions to be
encountered during the work. In setting the baselines, the geotechni-
cal baseline report (GBR) is allocating the risk of all conditions equal
to or less adverse than the indicated baseline conditions to the con-
tractor. Similarly, the financial risk of encountering conditions sig-
nificantly more adverse than the baseline is allocated to the owner.
While the baseline does not represent a warranty that the indicated
conditions will, in fact, be encountered, it does represent a promise
on behalf of the owner that the baselines will be considered in imple-
menting the differing site conditions (DSC) clause, and will weigh in
the determination of whether additional compensation for more
adverse conditions is justified.
The GBR must be prepared by geotechnical engineers familiar
with trenchless technology. Owners should retain design teams that
include individuals experience in the design and construction of
trenchless projects, and should ensure that those individuals will be
closely involved with the preparation and review of the GBR docu-
ment. The GBR should be developed after the design has been com-
pleted and the drawings and specifications have been advanced to a
substantial level of completion. Ideally, the GBR should be reviewed
by a knowledgeable engineer who has not been involved with the
preparation of the drawings, specifications, or GBR. This indepen-
dent “fresh look” is of critical importance in identifying and alleviat-
ing ambiguities that will inevitably exist within the GBR or between
the GBR and other contract documents.
The owner should be advised of the range of conditions that
could be encountered and the designer’s best assessment of the most
likely conditions to be encountered. The owner should also be
included in the process of setting the baselines for construction. This
should include an understanding of the reasonable range within
which the contractual baseline(s) might be set, including the ramifi-
cations of where the baselines are set on the bid prices and potentials
for change orders.
The Geotechnical Baseline Reports for Construction, published by
the American Society of Civil Engineers (Essex, 2007) provides rec-
ommendations for what should be included in the GBR and what
should not, and provides a checklist of items to consider when writ-
ing a GBR. This manual provides recommendations of the content
and wording to be used in baseline statements to improve their clar-
ity and precision, and presents illustrative examples of problematic
and improved practice in stating baselines. While GBR is recom-
mended for all types of trenchless technology projects, some owners
and may not consider it to be applicable for smaller trenchless proj-
ects (such as Mini-HDD, horizontal auger boring, or pipe ramming
operations).