Department of National Defence

DeptOfNationalDefenceThe Halifax Jetty replacement project is forecasted for completion in early 2019. 

By Kat Zeman

After 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 January 2019.

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 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.”

Overcoming Challenges

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.” Department of National Defence box

However, the Department of National Defence uses specialists and consultants that run computer simulations to determine safe vibration levels. “We have a good understanding of what it’s going to be like before we even start blasting,” Oram says.

The Department of National Defence also works closely with marine biologists and other consultants to ensure that it adheres to provincial environmental regulations regarding the treatment and disposal of dredging material. Special attention is paid to contaminants in the excavated material.

In addition, the Department of Fisheries and Oceans offers its expertise on the project and chimes in about the risk of disrupting aquatic life and damaging the underwater environment. “We work together in a collaborative way to understand the environmental impact and then come up with a compensation plan,” Oram says. “We’re firmly committed to do right by the aquatic environment.” 

One of these compensation plans involves creating new underwater habitats. Because any type of construction involving underwater blasting will cause some environmental damage, the Department of National Defence has offered to build artificial reefs. In this particular case, 75 reef balls made from poured concrete using casts, were installed in 15 groups of five each on the ocean to form the supporting structure for a new reef habitat.

Safety First

Safety is a top concern for the Department of National Defence, and the jetty project team is committed to creating a safe work environment. Contractors for the Halifax Jetty project – Dexter Construction Co. Ltd and McNally International Inc. – both follow performance specifications and a health and safety plan approved by the Crown.

The specs serve as a foundation for maintaining a safety regimen. For example, workers within a certain distance of water must wear flotation devices. In addition, workers also participate in tool box talks to review safety procedures.

Collaboration is Key

The Halifax Jetty project, though headed by the Department of National Defence, is a collaborative effort between several organizations. Key stakeholders in the Halifax Jetty project include the Department of Fisheries and Oceans, Halifax Port Authority, Halifax Harbour Bridges and Defence Construction Canada.

Oram has been with the Department of National Defence for almost 10 years and has learned lessons from the jetty project, including the benefits of collaboration. “Engaging all stakeholders is always the best way to proceed,” he says. “We’re working together, rather than creating an adversarial environment. We want to do our job and deliver something great for the military.”

The Department of National Defence maintains a vast infrastructure across Canada, which is being updated, in part, through projects funded by the Federal Infrastructure Investments Program. These projects include several jobs at Canadian Forces Ammunition Depot Bedford located within the Halifax Regional Municipality of Nova Scotia, as well as extensive work at CFB Halifax.

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