Geotechnical News June 2011
23
GEOTECHNICAL INSTRUMENTATION NEWS
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Who Should be Responsible for Monitoring
and Instrumentation During Construction?
John Dunnicliff
Introduction
We all know that geotechnical
construction of is not an exact science,
and that therefore monitoring often
plays a crucial role in ensuring that the
project site and surrounding properties
are safe, and meet the designer’s intent.
Monitoring often includes the use
of geotechnical instrumentation. If
significant decisions are to be based on
the monitoring data, it’s imperative that
data quality is maximized.
If instrumentation is used, the tasks
include:
1. Buying instruments
2. Installing instruments
3. Collecting data
4. Interpreting data
How can we ensure that these tasks
are assigned to the people who are most
likely to maximize quality?
The Golden Rule
The golden rule is:
The people who
have the greatest interest in the
monitoring and instrumentation data
should be given direct responsibility
for obtaining the data.
Or put another
way, who has the motivation to do these
nit-picking tasks with enough care?
Who has the motivation to
do these tasks with enough
care?
Who are the Candidates for
Task Assignment?
They are the staff of:
• The project owner
• The project designer
• The construction manager
• The general construction contractor
• Possibly a design/build contractor
• Often a specialist geotechnical
subcontractor.
The selection depends on the spe-
cifics of each project, on who has “the
greatest interest”.
The selection depends on
who has the greatest interest
If general construction contractors,
design/build contractors or specialist
geotechnical subcontractors (with the
agreement of the general construction
contractor) have initiated the moni-
toring program, clearly they have the
greatest interest, and all’s well. But if
the program has been initiated by the
designer of the project, personnel in
these three organizations may not have
enough motivation to ensure quality.
Let’s look at the options for this situ-
ation.
Options for Assignment of
Tasks 1, 2 and 3 when the
Monitoring Program has been
Initiated by the Designer of the
Project.
Let’s call these three tasks of buying
and installing instruments and
collecting data “field instrumentation
services”. Use of the conventional low-
bid procedure, whereby these tasks are
included as items in the construction
bid schedule, has often led to poor
quality data. Is there an alternative?
Yes, there is.
There are four specific reasons for
assigning responsibility for field instru-
mentation services to personnel select-
ed by the project owner or designer and
under direct contract with the project
owner.
There are four reasons for as-
signing responsibility to per-
sonnel under direct contract
with the project owner.
First Reason – Quality of Data
General construction contractors may
not have enough motivation to ensure
quality. Afew years ago a UK colleague
and I put together some ideas about
how to maximize quality when the
monitoring program has been initiated
by the designer of the project. We made
a strong plea for using a qualifications-
based selection procedure for field
instrumentation services. If you have
any interest, you can download these
ideas from
.
com/instrumentation_news.php
and
scroll down to the only entry for 2001).
Our preferred option is that the people
responsible for field instrumentation
services should be selected by the
project owner or designer and under
direct contract with the project
owner. Our publication includes
many comments from the technical
literature in support of a qualifications-
based selection procedure, which can
