Construction Today 2018 - Volume 16, Issue 3 - 137
power plant," Paul Thompson says. In
addition to the environmental benefits in
reducing the emission of greenhouse gases,
the plant is much more thermally efficient
than the plant it is replacing, resulting in
less fuel being needed to generate the same
MW, leading to a lower cost/MW.
Mechanical learned that the middle of the
Mid-Hudson Bridge provided a low point on
the Hudson River, with less than nine feet
of clearance. "We built the HRSG just low
enough to pass under [it]," Steven Thompson says.
Making the Move
The process of transporting the HRSG took
Durr Mechanical one-and-a-half days, but
the company spent eight months planning
and preparing for the move. This included
winning approval from the United States
Coast Guard and the United States Army
Corps of Engineers.
Durr Mechanical also hired "a permitting
consultant who was essentially the conductor for the permitting process," Steven
Thompson recalls, noting that the path to
permits can be quite involved.
The company also prepared for the
journey by taking into account wind and
wave forces, as well as possible obstructions
during the voyage. Through a study, Durr
In August 2017, the contractor moved the
HRSG with self-propelled modular transporters (SPMTs) similar to those used by
NASA to move the Space Shuttle. "[We also]
designed a substructure to the HRSG that
would allow these transports to drive under
it," Thompson describes.
The SPMTs slowly and carefully rolled
over a ramp onto a barge as they carried the
HRSG. "Once it was on the barge, we raised a
sigh of relief," Paul Thompson recalls.
But Durr Mechanical's careful work did
not end there. Instead, the company had
to make sure it was placed exactly where it
needed to be on the barge, and tied down
and secured in the correct way.
After it was finished, the barge, which
was pulled by three tugboats, transported
the HRSG to the Sewaren site. This process
earned Durr attention from local news
outlets as well as The Wall Street Journal and
"These means and methods have been
used before to bring stuff that was manufactured overseas into the United States,"
Thompson notes. "But it's never been done
on this scale in the United States."
When Durr Mechanical arrived at
the project site, it had to complete more
complex work, which essentially required
it to "do the loading process in reverse,"
Thompson recalls. The company first had to
re-ballast the barge and install new bridge
ramps to get the HRSG onshore.
Durr Mechanical then drove the generator across the project site slowly to the
anchor bolts and lowered it down. However, "There was very little room for error
when placing the things on the anchor
bolts at Sewaren," he recalls, noting that
the company had only an eighth of an inch
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