The Canadian War Museum (CWM) was designed to combine the aesthetics of a public display venue with the practical application of modern sustainable development. The architecture incorporates the notion of natural regeneration in the wake of the destructive forces of war. The museum is located on re-claimed brownfield on LeBreton Flats west of Parliament Hill in Ottawa. The building features non-level walls and floors designed to make visitors feel slightly off-balance, which in turn reflects the plight of Canadian armed forces personnel locked in international conflict. The ceiling, walls and floors are constructed with cast-in-place concrete. Water pumped from the Ottawa River is used in the museum’s three chillers to maintain a constant temperature of 21°C and then cycled as grey water into the toilets. Heat extracted by the chillers is channeled to the museum’s hot water tanks. Approximately 70 percent of the water taken from the river is returned about 5°C warmer than when it was removed with studies showing no negative environmental impact.
Concrete Products Used for this Project
- Type GU cement and flyash for 30,000 m3 of 15, 25, 30, 32, 35 and 40 MPa concrete — also Axim admixtures and fibres
- Cast-in-place concrete walls with an average of 30 percent flyash
- Cast-in-place double wythe exterior walls incorporate a vapour barrier and insulation to form an impenetrable rain screen
- Exposed concrete floors and concrete columns
- Exposed concrete slab ceilings
The Reasons Concrete Was Selected for this Project
Concrete was used extensively on this project as an economical and aesthetically pleasing construction solution. Concrete has the ability to provide an austere, yet artistic, visual effect to meet the needs of a museum that features both the triumph and misery of war. Concrete offers superior climate control—it safeguards against rapid indoor temperature fluctuation when outside weather changes. The ability to control climate saves energy and helps to preserve sensitive artifacts. Engineers believe the concrete should last 500 years plus, with scheduled routine repairs to joints, rain screen components, and other areas within the first 25 years.
Material of Choice for the Green Roof
Concrete was the material of choice to support a foot-thick covering of earth on the low-maintenance 10,684 m2 roof that supports native self-seeding grasses. The museum’s green roof is the largest of its kind in North America. Designers favoured the green roof to express the architectural theme of “regeneration.” It has the additional benefits of providing greater thermal insulation than the minimum required by the building code. Designers initially examined installing a steel truss roof, but concluded that the amount of steel required to support the weight of a green roof was a more expensive option than concrete.
Contributes to the Aesthetics of the Museum
ALL PHOTOS: Harry Foster, Canadian Museum of Civilization
Many walls bear the textured wood grain imprint of the boards and plywood that comprised the forms to provide a deliberate trench and bunker effect. The plywood, which was often placed in a mosaic pattern, could be removed once the concrete was set and re-used in a different area to save on costs. Gaps were left in the formwork to affect an architecturally-pleasing relief on the exposed surface.
Meets Sustainable Design and Construction Objectives
Where slow curing was not critical, most concrete walls are composed of 30 percent flyash. But flyash could not be incorporated into the floors or ceilings due to curing time constraints. Concrete facilitates constant interior air temperature, quality and humidity. Air characteristics must remain constant day and night to preserve displays and artifacts, and concrete minimizes daily and seasonal exterior fluctuations. The concrete exterior is also considered to be one of the most secure materials available to protect Canada’s national treasures. As well, the museum surpasses building code regulation for seismic constraints. The project was delivered on time and on budget.
|Owner: Museum of Civilization for the Government of Canada|
|Architect||Moriyama & Teshima Architects (Toronto) Griffiths Rankin Cook Architects (Ottawa)|
|Structural Consultant||Adjeleian Allen Rubeli|
|Mechanical Engineer||The Mitchell Partnership|
|Electrical Engineer||Crossey Engineering|