Building the Trans Mountain Expansion Project - Westridge Marine Terminal

Abstract: The Trans Mountain Expansion Project (TMEP) is one of the largest infrastructure projects ever undertaken in western Canada, with a capital cost in excess of CAD$30 billion. It represents a project of vital strategic national interest to Canada, connecting landlocked oil reserves in Alberta to tidewater near Vancouver, BC. The project involves twinning an existing 1,150 km pipeline between northern Alberta and the pipeline terminus at the Westridge Marine Terminal (WMT) in Burrard Inlet, BC. The WMT comprises three new vessel loading berths, each capable of accommodating up to 125,000 DWT Aframax vessels. The new berths triple the oil export capacity of the existing terminal which has operated at Westridge since the 1950’s. The new berths had to be built immediately adjacent to the original berth without causing disruption to the ongoing operations. After more than six years of construction, the WMT is currently nearing completion as of mid 2024.
The construction process followed one of the most lengthy and complex federal and provincial regulatory processes in Canadian History. The project approvals included 156 mandatory Conditions enforced by the Canada Energy Regulator, many of which were focussed on reducing the environmental impacts of construction.
This paper focusses on the construction contract project delivery method and some of the construction strategies used on the project. An Early Contractor Involvement delivery model was used whereby the Owner selected a construction Contractor during the design process, and directed the engineering Consultants to work closely with the Contractor to ensure the design was optimized to suite the Contractor’s preferred means & methods. Extensive mitigation measures were put in place during construction to reduce the impact on the surrounding communities and aquatic environment, and an extensive artificial reef was constructed within the project footprint to offset or compensate for habitat impacts.
The marine construction techniques used on the project where highly technical in nature, due to the scale of the project, the size of the individual components, the depth of the water, the poor soil conditions, environmental restrictions, and installation tolerances. Overcoming these challenges required extensive marine construction engineering, and significant coordination between the construction and design teams.
The pile jackets for the mooring and berthing dolphins weighed up to 360 tonnes and the equipment used to deliver the project and install the jackets included the largest heavy lift derrick barge on the west coast of North America. Installation of the twenty-four jackets required a sophisticated template that was able to accommodate 3 different pile diameters, twice daily 5m tidal changes, and meet a pile installation tolerance of 75mm. Water depths of over 24m required that the piles be spliced while in the template so driving could progress. The heaviest piles lifted were 80m long and weighed up to 200 tonnes, which had to be tripped off the end of the barge to accommodate the limited boom length for the heavy lift derrick barge. Multiple examples of interesting and challenging marine construction engineering designs and innovations that will be covered in this paper.

How does this project / topic contribute to the advancement of the industry and profession?: This project represents a new high-water mark in terms of the size, scale and complexity of marine terminal construction in British Columbia. The techniques used for pile handling and installation throughout the project pushed the boundaries of the capacity of the floating equipment available along the west coast of North America. We will present the marine construction engineering required to accomplish a successful delivery of this project. Additionally, good coordination amongst all stakeholders throughout the design and construction of the terminal was essential to a successful project, and we will discuss the lessons learned through the project.

Does the project / topic implement new and innovative techniques, materials, technologies, and delivery methods?: Yes, the project involved some the largest steel piles ever used in British Columbia, with some individual piles being over 330m long and over 220 tons. Construction required the use of the D.B. General, the largest floating derrick crane on the West Coast of North America. An innovative “noise shroud” was used to surround the pile hammer to suppress the noise above water, while a high-capacity bubble curtain system was used to suppress underwater sound waves. Full time environmental monitoring staff, with the authority to suspend work, were on hand to monitor underwater noise and keep watch for marine mammals.

What was the most challenging aspect of your project / topic and how did you handle it to ensure success?: The environmental requirements were one of the most challenging aspects of the project. The underwater acoustic and marine mammal requirements were extremely rigorous and demonstrated the need for numerous engineered systems to address these requirements, from multiple-staged air-curtain systems, underwater discos to deter fish, and daily commercial divers to perform inspections and cleaning of the air curtain systems. To ensure success we established good relations with our client’s environmental team, DFO, Vancouver Port Authority and the Canada Energy Regulators and worked together to create engineered systems capable of keeping our equipment within the limitations of the environmental permit requirements.

Who is the target audience for this paper?: Maritime engineers, environmental scientists, coastal engineers, marine terminal operators, construction engineers, general contractors, policy- and decision-makers that have influence over the construction and operation of port facilities will have the most to gain from this paper. The scale of the projects like WMT carry with them increased risk to all of stakeholders. Owners, designers, and builders all have an interest in delivering successful projects, and this paper will present how large, higher risk projects which push the boundaries of what can be accomplished with existing technology and advanced techniques can still be successful by way of coordinated planning and execution.