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Costs of
Tr n hi ss
Prol ts
By Jack U. Zhao and Balvant B. RaIon;
renchless technologies are
increasingly used for construc-
tion and rehabilitation of
buried utilities such as gas
pipelines, water distribution systems,
sewer collection systems and
drainage culverts.
Under the general umbrella of
trenchless technologies, there are a
wide range of no -dig techniques,
including cured -in -place pipe (CIPP),
microtunneling, tunneling, horizontal
directional drilling (HDD), sliplining,
fold- and - reformed pipe, pipe jacking,
pipe bursting, spot repair, spiral
wound and shotcrete.
Engineers need to keep abreast not
only of existing and emerging trench-
less technologies, but also of their asso-
ciated costs in order to make appro-
priate decisions on rehabilitation pri-
ority, budgeting and scheduling.
About 200 contract- winning bid
prices were compiled from the
"Jobs Let" section of the Trenchless
Technology
(1993-
2002) and
o t h e r
sources
(Zhao and
R a j a n i,
2002) for
projects let
by various
municipali-
ties in the
U n i t e d
States and
C d
Some of the reported project costs
included the construction of a small
quantity of access holes (manholes),
which could not be separated in this
cost analysis. Inflation was taken into
account using the published Building
Cost Index (ENR, 2002).
Table 1 (on page 28) shows the
average direct costs (U.S.) of 15
trenchless techniques, together
with that of the open -cut method.
The cost data shows that the most
costly trenchless technique is
microtunneling at $49.8/ft followed
by pipe jacking and tunneling at
$23 /ft and $20.4 /ft, respectively.
These three techniques are also
more expensive than the open -cut
method ($19.3 /ft).
The least costly trenchless tech-
nique is lining at $6.3 /ft. Also shown
for information are some new
processes and those with only one
data set. Figure 1 (shown below)
presents the costs in dollars per
Engineers need to
keep abreast not only
of existing and emerging
trenchless technologies,
but also of their associated
costs in order to make
appropriate decisions
on rehabilitation priority,
budgeting and scheduling.
linear foot in four consecutive
diameter ranges, representing small,
medium large and very large pipes.
As shown, costs of all trenchless
projects increase with the increase
in pipe size, except for sliplining
and open -cut. The average costs of
large or very large categories for
these two methods may not be
representative due to the small
number of data sets available.
The general trend of increasing
cost as pipe size increases is due not
only to the increase in pipe material,
but also to the increased level of
complexity, mobilization/demobiliza -
tion cost
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Average bid prices of trenchless projects for four diameter ranges, including open -cut. The data that
could not be separated into the four diameter ranges were not used in generating the figure,
ana a. —
www. trench lesson llne -com
and diffi-
culty of
carrying
out the re-
habilitation
w o r k .
S o m e
trenchless
methods
(microtun-
neling, tun-
neling and
HDD) for
pipes larg-
April 2003 TRENCHLESS TECHNOLOGY 27
er than 38 in. in diame-
ter appear to be less eco-
nomical than the open -
cut method. How- Trenchle
ever, selection of trench-
less rehabilitation de-
pends not only on direct
cost, but also on social
cost (McKim, 1998).
Lower social costs often
make trenchless rehabil-
itation the first choice in j
congested downtown
areas. Furthermore, con-
struction /rehabilitation
options for certain types
of construction (e.g.,
large tunnels) are
limited.
Although the reported
contract- winning bid
prices provide valuable
information on cost esti-
mation for trenchless
projects, final project costs may vary
due to unforeseen site conditions.
In addition, each project is unique
and sound engineering judgement
in the selection of options can never
be overemphasised.
McKim, R. A. 1998.
Table 1. Average awarded costst of trenchless projects Bidding strategies for
trenchless technolo-
f data gies. Cost Engineering,
40(3): 37 -41. Trenchless
Technology. 1993 to
2002. Trenchless
Technology, Inc.,
Peninsula, OH, U.S.A
Zhao, J.Q. and Rajani,
B.B. 2002. Construction
and Rehabilitation Costs
for Buried Pipe with a
Focus on Trenchless
Technologies, Research
Report RR -101, Institute
for Research in
Construction, National
Research Council of
Canada, Ottawa, ON,
Canada. www.nrc.ca/
irc 1fulltext 1rr101.
ss Method
dia.lm
_ ngth)
n
Microtuneling 51
Pipe Jacking 6
Tunneling 25
HDD 12
Spiral wound 2
Pipe bursting 12
Shotcrete 3
Sliplining 16
CIPP 42
Lining 7
Open cut (for comparison) 17
New trenchl processes or processes with only 1 dat set
Cement mortar lining 4.7 0.9
Chemical cleaning 3.7 0.7
Fiberglass liner 9,7 1.9 New process
Steel liner pipe 14.2 2.7
Structural panels 17.3 3.3 New process
t - For the reported projects that contained more than one diameter, the average diameter
was estimated for determining average costs. All costs are expressed as the 2002 (US)
dollars ($US 1 = $1 -48 CDN.).
L
References
Average cost
($lin. dia /ft, ($/mm
length) le
49.8
9.,i
`L3.0
4.3
20.4
3.9
14.3
2.7
13.1
2.5
11.7
2.2
7.7
1.5
7.5
1.4
7.0
1.3
6.3 1.2
19.3
3.7
ENR. 2002. Engineering News -
Record: Building Cost Index History
(1915 - 2002),
www. enr. com /cost /costbci.asp. UJAP
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Grde 17 on reader service mid.
28 TRENCHLESS TECHNOLOGY April 2003
#n
records
Jack Q. Zhao, Ph.D., PEng., and
Baivant B. Rajani, Ph.D, are researchers
with the Institute for Research in
Construction, National Research
Council Canada, Ottawa, Ontario,
Canada.
Grde 7 on reader service card.
www.t,
encMessonline.com
ECI currently has seven drilling rigs and is currently
building a 1.1 million -lbs rig, which is expected to be oper-
ational by June. The company's rigs range from two road
boring machines and 5 mid -size ones up through rigs with
500,000 lbs of push /pull. All of the mid -size rigs are from
American Augers.
The company's geographic operating territory has
ranged from the continental United States,Alaska, Canada,
Japan and Southeast Asia. ECI is also currently active in the
United States, Canada and Puerto Rico.
ECI is a full- service company, performing HDD services
for water, sewer, CATV, gas pipeline, telecommunications,
electric power and the like.As most HDD companies did,
ECI became heavily involved in telecom work in the late
1990s, with a specialty in land -to -ocean beach approach
bores. ECI also performs river crossings.
The principle drilling personnel for ECI include: William
Gardner, vice president of operations; Doug Steen, general
superintendent; Scott Conway, drilling superintendent;
David Sewell, drilling superintendent; Randy Welborn,
drilling superintendent; and Barry Nailing, assistant drilling
superintendent.
ECI completed a unique project (see left photo) in
which a 20 -in. HDPE conduit was installed in New Haven,
Conn., under the New Haven Harbor. The drill was
only 2,000 ft long in rock but involved several marine
vessels and barges. The vessels couldn't position them-
selves far from the bore exit due to oyster beds behind the
Circle 76 on reader seance card.
40 TRENCHLESS TECHNOLOGY April 2003
Orde 77 on reader service card .
www.trenchlesson line. Iona
Precise Directional Boring Inc. nation of large pipe, the bore's length
Millersport, Ohio and the fact that they were boring
under four lanes of traffic made this
Ph: (740) 808 -0680 project particularly challenging.
Precise Directional Boring Inc. has
been working in the HDD industry
since 1997. The company's founders
are Chad Crist and Matt Upp.
Like most directional drilling
contractors, cable and telecom work
was Precise Directional Boring's
springboard into the HDD market-
place. However, the company quick-
ly realized the need to diversify its
work and is now concentrating
much of its efforts on the water and
sewer industries.
Environmental Crossings Inc.
Traverse City, Mich.
Ph: (231) 929 -1242
Web site: www.ecihdd.com
Environmental Crossings Inc.
(ECI) has been in business since
1992, formed by a couple of oil
and gas producers who believed
there might be a future in HDD.
A few experienced HDD personnel
were hired, a couple of whom
became partners. ECt began work-
ing primarily in rock in the
Northeast, which offered a niche
business at the time.
Precise Directional Boring current-
ly owns and utilizes 7 Ditch Witch
rigs: (2) JT 2720, (2) JT1720,
(2) 920 and a 4020. The company
primarily drills in Ohio and northern
Kentucky, specializing the water
and sewer markets. Crist and Upp
say that the emergence of HDPE,
restrained -joint PVC and restrained -
joint ductile iron in the water
and sewer markets enabled the use
of directional drilling as a
reasonable construction method
for installation.
Crist and Upp — who both are
heavily involved in the company's
day -to -day field operations — say that
they began educating engineers and
owners about the HDD process and
its benefits. They also began leverag-
ing their deep relationships with
their contractor clients to convert
projects that they were awarded to
directional drilling.
One project that Precise
Directional Boring recently complet-
ed involved the installation of a 24 -in.
HDPE waterline under U.S. Interstate
71 in southern Ohio (see above
photo). The length of the bore was
480 If. Christ and Upp say the combi-
THE HDD COMPANY, INC.
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With The Utmost Concern To
Every Detail. Just Ask our Clientsl
The HDD Company, Inc.
P.O. Box 621028, Orangevale, CA 95662 -1028
Bus: 530.676.5705 Fax: 530.676.3605
Cell: 916.801.7215 E -mail: hddcoinc @aol.com
n _ .- _ T_ 1a)—l' CnY VA. J
G 71 nn reader service cord
wwwlrench lesson line. com April 2003 TRENCHLESS TECHNOLOGY 39