Award of Excellence Mount Pleasant Substation

Located at 338 West 6th Avenue, the 400-MVA Mount Pleasant Substation is an integral part of the most significant investment in central Vancouver’s electrical system in 30 years. It is the only publicly-visible portion of BC Hydro’s Vancouver City Centre Transmission Project (VCCT). The VCCT project increases the reliability of the electrical supply throughout Vancouver and meets the growing demand for power in the South False Creek/Mount Pleasant area.

BC Hydro required that the substation would be highly reliable after an earthquake. It had to be an aesthetically pleasing design, with durable materials to minimize the maintenance requirements.

Traditionally, substations have very functional and pragmatic designs, often with large metal-clad equipment and exposed conductors inside chain link fence enclosures. But the Mount Pleasant Substation is much different. Through a stepped-massing design, creative use of materials, dedicated green space and public art, the project fits into the urban fabric and is the first substation on record constructed to meet LEED Silver requirements. It satisfies complex urban design issues with a design that is the result of public consultation and integrated design processes.

WSP was the prime consultant and provided project management, structural, mechanical and electrical engineering services. A combined team of 50 people from WSP and BC Hydro worked together to complete the design within many constraints.

Small space – large equipment

The building is located in a residential neighbourhood of houses, apartment buildings and low-rise commercial buildings. The urban site meant using a smaller site than normal and locating all equipment indoors. Areas of the site were also dedicated to public green space and landscaping to meet the city’s development guidelines.

With the fixed and constrained site it was not possible to enlarge the building to suit the equipment. Consequently, the building was designed with three floors with a floor-to-floor distance of 9 metres. One complete level is located below grade to reduce the exposed height of the building. This feature places the bottom of the structure below the water table and thus required a tanked foundation design and groundwater drainage system.

For safety, all interior and exterior metal components are connected to a complex station grounding grid to eliminate electrical shock hazards. Extremely detailed design was required to introduce ground wires into metallic building components where they are not typical, such as aluminum window systems, wall cladding, flashings and even handrails.

While having to meet seismic and post-disaster requirements, the building structure had to be slim enough to provide maximum space inside for the significant clearances required for equipment and cable penetrations.

Grounding

The heavily reinforced walls also needed to accommodate large grounding cables. The rebar was electrically isolated to prevent its heating due to inductive currents generated by power conductors. Both epoxy-coated rebar and fibre-reinforced rebars were used. Since the walls needed to be as thin as possible, the clearances for rebar were minimized. All the walls were poured using a self-consolidating concrete.

BIM and 3D minimized design modifications

Due to the complexity of the building and equipment systems, the facility was designed using BIM software. All process equipment and interconnecting cable trays were also modelled in 3D. This approach enabled the systems to be checked for conflicts and generated useful information for pricing the project. Only minor modifications were required to the building to accommodate major equipment that arrived after the building was 90 per cent complete.

The project took six years from conceptual design to construction completion in 2013, and the final cost was within budget. cce

Project name: Mount Pleasant  Substation, Vancouver, B.C.

Award-winning firm (prime consultant): WSP Canada (Sean Kennedy, P.Eng., Ron Parker, Arnold Con, P.Eng., Nasser Koochek, P.Eng., David Woo, P.Eng.)

Owner: BC Hydro

Other key players: Architecture49/PBK (architect); Recollective (LEED); BKL (acoustics); PCL Constructors Westcoast (contractor); Durante Kreuk (landscape).

Supplier: Trane (HVAC equipment)