Mainwaring Substation Shoring
in Vancouver BC
The Mainwaring Substation Upgrade required a temporary shoring system to facilitate excavation for new infrastructure adjacent to a live BC Hydro substation. Dense granular soils, limited working space, and the need to maintain street access for local residents demanded a coordinated approach to design and installation. TerraCana delivered 32 driven soldier piles with pre-drilling, completing the project in less than a month.
The Challenge
The Mainwaring Substation is an active BC Hydro facility, and all work took place immediately adjacent to live high-voltage infrastructure. The site had limited space available for installing the shoring system, and the surrounding residential neighbourhood required that street access be maintained throughout construction. Subsurface conditions added further complexity. Dense granular soils made it impossible to drive the soldier piles to depth simply; every pile location had to be pre-drilled before installation. Coordinating the shoring design with other trades was essential to minimize the extent of excavation and develop a buildable system within the site’s tight constraints.
The Solution
TerraCana worked with StrucTec, who designed the temporary shoring system, to coordinate the layout and minimize excavation while keeping the system constructible in the confined space. The team pre-drilled all 32 soldier pile locations using a Soilmec SR65 drill rig to penetrate the dense granular soils, then drove the piles with an excavator-mounted Movax SP100 vibratory hammer. Pile lengths ranged from 6 to 12 metres, depending on subsurface conditions. The shoring system enabled the excavation needed for a new building and high-voltage electrical duct banks as part of the substation upgrade.
The Outcome
Technical Specifications
Key Outcomes
