Underground Construction - July 2017 - 42

NEWPRODUCTS LATEST INDUSTRY DEVELOPMENTS

General Contractor Tackles The Challenge By Jamie Jackson
Of High-Profile, Urban Job Site

When Corinthian Contractors was
awarded a subcontractor bid in late
2015 to do excavation, material hauling and placement service
work during phase two of the
Dulles Corridor Metrorail Project,
owner Jamie Doll knew he would
need the right mix of construction
equipment to efficiently complete
the job.
Doll, a seasoned construction
professional, was in the process
of purchasing two Doosan crawler
excavators, a DX300LC-5 and DX235LCR-5, and a Doosan DL250-5
wheel loader from John "Stu"
Munsell at the H&E Equipment
Services branch in Dundalk, MD.
His timing couldn't have been
better, because the trio proved to
be effective on the underground
infrastructure project.
The Metrorail expansion project would require Corinthian
Contractors, a full-service general
contractor, to dig 15- to 18-foot
trenches several thousand feet in
length, and install eight manholes
and dry utilities to provide electrical power for a new traction power
substation near the Dulles Interna-

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tional Airport. The new substation
is part of a two-phase, 23-mile
extension of the Metrorail system
that will connect rail service from
the Dulles Corridor to downtown
Washington, D.C. When complete,
it will be officially known as the
Silver Line.
"We knew we'd have some
work - specifically the Metrorail
project - and when we're done it
will probably be a two-year project.
I saw the need for the DX300LC-5
and DX235LCR-5 with the machines' power-to-weight ratio and
the capability of the equipment,"
said Doll.

More equipment
Now more than a year into the
project, Doll has added three more
Doosan crawler excavators, a
DX85R-3, DX140LCR-5 and DX180LC-5, plus another DX235LCR-5 and DX300LC-5, respectively. The pair of DX235LCR-5s and
the two DX300LC-5 excavators are
dedicated to the Metrorail project.
The equipment has proven it is
capable of not only handling the
heavy workload, but also navigat-

ing the crowded job site with ease.
The reduced tail swing feature
of the DX235LCR-5 excavator has
been an advantage. The excavators
are positioned along the median of
the Dulles airport toll road, which
remains open to traffic during
construction. The only thing separating the heavy machinery and
nearby traffic is a Jersey barrier.
The DX235LCR-5 is designed to
work on congested job sites without blocking traffic in the adjacent
lane, and without sacrificing digging and lifting performance.
"When you're working behind
barriers, that reduced tail swing
is No. 1. You can have confidence
that the machine isn't going to
impede traffic or other contractors
working in the area," Doll said.
The DX300LC-5 duo has been
tasked with the wayside area of
the project where digging through
rock presents a challenge. Even
in less-than-ideal conditions, the
DX300LC-5 is more than capable
of handling the task. The permanently sealed and lubricated tracks
are designed to maximize uptime.
"It's muddy, it's bumpy and when

it rains, the ground is very thick,"
Doll stated.
The Doosan excavators are also
well-suited to a wide variety of
tasks in this large-scale project,
from removing thick overburden,
to forming trenches specifically for
manholes. "The excavators have
the capability to dig both large
areas and small areas effectively,"
Doll added. "You don't need a different machine to match different
parts of the job."
As the Metrorail project wraps
up, Corinthian Contractors has
more high-profile projects lined
up, including a road-widening project that Doll says is another ideal
application for the Doosan excavator tag team. "The cut is accomplished with the DX300LC-5 and
the utilities are installed with the
DX235LCR-5," he said.
Doll knows the DX235LCR-5
will provide yet another advantage
in the transition. "The DX235LCR-5 can be hauled on our lowboy
(trailer) from site to site," he said.
The DX235LCR-5 excavator is
the maximum weight that can be
hauled without a permit. "Every
Underground Construction July 2017

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Underground Construction - July 2017

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