Contruction Today - July/August 2017 - 98
Institutional | DEPARTMENT OF NATIONAL DEFENCE
THE HALIFAX JETTY REPLACEMENT IS FORECASTED FOR COMPLETION IN EARLY 2019. BY KAT ZEMAN
fter two years of construction
work, the Canadian Forces Base
(CFB) Halifax Jetty replacement
project in Halifax, Nova Scotia, is
more than halfway complete. The Department of National Defence forecasts that the
$90 million jetty will be commissioned by
The new 247-meter-long by 29-meter-wide concrete jetty, located on the
waterfront of Her Majesty's Canadian Dockyard, is the former site of two deteriorating
jetties that were last used in the 1990s. "We
have removed all the parts of the old jetties
that were there," says Lorne Oram, project
manager for the Department of National
Defence. "The old structure was of wood and
supported on timber piles."
The new jetty will have a water depth of
roughly 13 meters and a large backup apron
area. It is designed to be an all-weather jetty
primarily for the berthing and connectivity
services of operational vessels, mainly of
the Arctic Offshore Patrol Ship fleet. The
jetty will feature steel decking, supported
by a series of six cast concrete caissons and a
utility tunnel to house the services running
to the jetty mounts.
The two former jetties were built using a
pile construction method - piles of timber
driven into the ground to support the structure. But the new jetty will be different.
"The new one is being built with different
* Project: Halifax Je y eplacement
* Construction budget: $90 million
* Headquarters: Halifax, Nova Scotia
"We work toge er in a collaborative way to understand e
environmental impact and en
come up wi a compensation
plan." - Lorne Oram, project manager
CONSTRUCTION-TODAY.COM JULY/AUGUST 2017
» The jetty will be supported by poured concrete caissons that are reinforced with steel rebar.
technology," Oram says. "It is being built
using caisson construction."
The jetty will be supported by poured
concrete caissons reinforced with steel
rebar. Oram calls it a time-tested, proven
technology for marine structures. "The caissons become a very durable and resilient
structure," he says. "They generally last 50 to
60 years and require less ongoing maintenance. We went with what typically tends to
be a more durable solution."
Like most construction projects, the Halifax
Jetty has faced challenges. Two of its major
challenges concern salt residue and the
blasting required to excavate and level the
site. "Giant structures need a reasonably
level surface on the ocean floor," Oram says.
"When you excavate, you encounter silt and
then glacial till before you hit bedrock. But
you can't dig bedrock. You have to blast it.
So there's concern for the marine habitat
and local residents because we have to
set explosives into the bedrock, and these
explosives cause vibrations that can be dangerous to aquatic life at intense levels."
However, the Department of National Defence uses specialists and consultants that
run computer simulations to determine safe