Underground Construction - April 2018 - 20

4th in a Series
James Anspach | UESI

Modern Utility Investigations to
Eliminate Some Project Risk
Editor's Note: This is the final installment of an exclusive four-part series outlining the risks
of modern underground utility infrastructure construction and rehabilitation work.

In Part 1, we introduced the concepts of underground uncertainties in infrastructure work. In
Part 2, we looked specifically at
how contract language allocates
the resolution of risks of underground uncertainties of existing
conditions (geotechnical data,
utilities, and Constituents of
Concern) between the engineer,
contractor, and project owner. In part 3, we looked at how
Geotechnical Baseline Reports
are used to avoid disputes over
differing site conditions and
"base-lining" bids. This last article
looks at how ASCE 38, Standard
Guideline for the Collection and
Depiction of Existing Subsurface
Utility Data, serves as a template
to perform adequate modern
utility investigations that can be
used to eliminate some amount
of project risk during project development, and assist the design
and utility engineer in managing
the remaining risks.
The concept of a utility investigation ranges from doing virtually nothing; to investigating the
current underground conditions; to using every conceivable
method to try to find out the
presence, location and condition
of underground utilities. But the
ends of the spectrum are not
normal. With study after study
showing that one of the top reasons for project delay claims is
that utilities are not shown correctly on plans, we need to bring
our technology and practices
up to date to solve the problem.
Many utility investigation techniques and methods are mired
in practices that may have been
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APRIL 2018 | UConOnline.com

ASCE 38 basically says: a thorough
utility investigation takes the results of a
comprehensive, big-toolbox geophysical
search for known and unknown utilities,
and integrates them with existing records
and physical evidence.
relevant in the 1980s, but should
have limited use in today's world.
What are the last century's
practices? Mostly, they are reliance upon information from
others that cannot be controlled
as to quality and comprehensiveness, and excavation at select
points to try to either confirm
this information from others, or
maybe get lucky and find something new. We see this procedure
many times on design-build projects, where utility records and
One-Call marks are used, along
with many test holes, to accomplish the utility investigation.
Utility records are notoriously
inaccurate, incomplete, missing,
never made, not available, difficult to interpret and not referenced to a recoverable datum.
Test holes are destructive, expensive, time-consuming, disruptive
to traffic and only give information at a spot location.
What is the solution? Basically, it is applying competent
geophysical techniques as early in the project development
process as possible. Geophysical techniques have had major
improvements in hardware and
software continuously since the
1970s and, yet, these techniques
are rarely applied by the project
owners and their engineers.

When used to any extent, it's
generally by persons with little
to no training in geophysics or
the instrumentation. Most of the
time, these services are applied
by multiple parties, with no coordination between them to fully
cover the project limits or ranges
of conditions. I'm talking about
One-Call services, developed and
used for damage prevention for
known utilities, and maybe GPR
services performed by untrained
people.

Advances
Advances in geophysical technologies for detecting utilities are
taking place around the world.
The European Union had its
ORFEUS (Optimizing Radar
to Find Everything Under the
Street) program. England had
the Mapping the Underworld
Project. And the United States
had its Strategic Highway Research Program that developed multi-channel GPR and
Time-Domain Electromagnetics
specifically geared towards utility
detection. Pipe and cable locating devices are some of the most
sophisticated geophysical tools
on the planet in recent years, and
yet very few technicians know or
are taught to use their full range

of capabilities, or have a full
range of frequencies and antennas available to them.
ASCE recognized the principles of a good utility investigation back in 1996 when it started
its standards committee to develop ASCE 38. This standard has
stood the test of time, but is still
used only sporadically by project
owners and engineers, mostly because of ignorance or a desire to
gamble that utilities will not be
an issue on their project. ASCE
38 basically says: a thorough utility investigation takes the results
of a comprehensive, big-toolbox
geophysical search for known
and unknown utilities, and integrates them with existing records and physical evidence. Test
holes are performed only where
needed, virtually eliminating the
issues of "dry" holes. It's that
simple.
All of the utility investigation
takes place under the direct responsibility of a licensed professional engineer with training and
working knowledge of surface
geophysics, engineering surveying, utility construction and
design principles, utility conflict
identification and resolution,
and utility risks as they pertain
to the project. This professional
is becoming defined as a utility
engineer, and is one of the reasons for the genesis of ASCE's
Utility Engineering and Surveying Institute.

ASCE 38
Studies by Purdue, Penn State,
University of Toronto and others
consistently show a large return

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Underground Construction - April 2018

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