Singapore - Trenchless International

October 2010 - Trenchless International PROjeCts
Piloting to success in jacksonville
by Stephen Tait
Mears Group, Inc. recently completed a 7,400 foot horizontal directional drilling (HDD) bore
in Jacksonville, Florida, US, a design-build project that allows a regional energy producer to
expand its natural gas pipeline to serve new facilities.
TO cOMPLeTe The project, Mears
drilled a 7,400 foot pilot hole beneath
the st Johns River at a depth of
130 feet below river bottom to install the
16 inch steel pipe. It is an essential link in a
50 mile pipeline that ends at the
Jacksonville Electric Authority (JEA)
Greenland Energy Center.
though just 1.4 miles of the 50 mile
pipeline, which is owned by tECO
Peoples Gas, the section under the st.
John’s River proved the most daunting in
planning stages.
Director of Engineering for tECO
Peoples Gas Mark Haney said “this was
the biggest obstacle to go from one side
to the other.”
HDD was virtually the only option to
install the pipeline through that area. Mr
Haney said “Other than HDD, there were
no other good options.”
But project officials said the timing of
the project was also a major issue.
Mr Haney said that the pipeline providing
service to the power plant will
be operational by 1 January 2011. that
means JEA was dependent on the pipeline
being in place in time to move
forward on the operation of the power
plant. to help ensure a timely project,
The Mears rig in action.
tECO hired Mears to complete a designbuild
project.
Project Manager for J.R. Giese
Operations–Mears’ sub-consultant–John
Fluharty said “If it is not built on time you
literally have a billion dollar power plant
there with no fuel.”
Mr Fluharty said design-build allowed
Mears to drill a pilot hole months in
advance to pulling product pipe to ensure
the project was feasible.
“tECO wanted to know that early
enough in the process so they would
know if they needed to go in another
direction, and wanted a true partnership
put together so they could work out all the
issues related to this special feasibility
hole we did in advance,” Mr Fluharty said.
Design-build is relatively new to the
HDD industry, Mr Fluharty said.
Design-build offers a subtle but important
difference from the typical procedure
for HDD projects. In the typical process,
a company such as tECO would hire an
engineer to develop plans, procure a
construction company to implement those
plans and then construct the project
– often called design-bid-build. Designbid-build
requires multiple contracts.
With design-build, however, a single
company is hired to engineer and to build
the project, all under a single contract.
susan Hines of the Design-Build
Institute of America says utilising designbid-build
can create contention between
the engineer or designer of a project and
the company that constructs the project.
she said it creates a disconnect between
the two parties that can often turn contentious
because of concerns of liability
and litigation.
For instance, Ms Hines said when the
construction company finds changes
need to be made to designs during
“Other than HDD, there were
no other good options.”
construction, it takes paper work and
dialogue for the changes to be approved
and implemented.
“It slows things down a lot,” Ms
Hines said.
In the end, design-build projects help
to improve two important aspects of any
project – money and time.
Design-build projects cost at least 6 per
cent less than design-bid-build projects
and are constructed 12 per cent faster,
according to the Design-Build Institute of
America. At the same time, the institute
reports that design-build projects earned
the highest owner satisfaction than other
project concepts.
“One of the main advantages of designbuild
is the fact that everyone on the
design and construction job is on the
same side,” Ms Hines said. “they are all
sharing in the risks and the rewards of a
job well done.”
she added, “Owners save money, they
save time.”
Mears drilled the feasibility pilot hole for
the project in November 2009 and product
pipe was pulled in April 2010.
Mears Project superintendent Mike
Maxwell said the crew drilled from both
sides of the st Johns River and intersected
the two holes under the river – a waterway
lined with stately homes and used mostly
for recreational purposes.
A 330,000 pound rig was used for the
pilot hole on one side of the river and a
140,000 pound rig was used to drill from
the opposite side.
Mears utilised its 500,000 pound
rig to perform the reaming and to pull
the product pipe through the hole, Mr
Maxwell said.
Additionally, Mr Maxwell said, the crews
reamed the bore to 24 inch diameter and
then swabbed the hole before pulling the
product pipe. the crew drilled through
sandy silt before making it to clay for the
drill’s running depth.
“It was fairly easy going; we were able
to use a jetting bit all the way through,” Mr
Maxwell said.
Mr Maxwell said the length of the drill
combined with the unique aspects of the
job, made it a satisfying accomplishment.
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PROjeCts
October 2010 - Trenchless International