Canadian Consulting Engineer

Destination Africa

Designing a zoo building is a project unlike any other. You have to simulate exotic and strange environments, and you certainly have to measure user satisfaction a lot differently. When the colobus mo...

December 1, 2004   Canadian Consulting Engineer

Designing a zoo building is a project unlike any other. You have to simulate exotic and strange environments, and you certainly have to measure user satisfaction a lot differently. When the colobus monkeys moved into their new glass home at the Calgary Zoo, they were so excited about the structure “they spent the first week up in the trusses doing inspections and admiring the view,” explain the architects at BKDI. As for the gorillas, within five minutes of entering the building they had found the one part of the structure that makes a noise when banged upon. One gorilla then tested the strength of the glass by leaping at it from five feet away.

Planning and designing Destination Africa at the zoo, which is located on an island in the Bow River in downtown Calgary, was a five-year process of intense consultations. Designers, curators, zoo staff and animal keepers, horticulturalists, volunteers and focus groups were involved. The designers visited other zoos in North America to learn about good practices, and from early in the project all the consultants worked as an integrated team

The $32.5-million project covers a 2.4-hectare site (20% of the zoo island) and includes the 3,000-s.m. TransAlta Rainforest building, the 2,000-s.m. African Savannah building, a 350-seat Safari Lodge conference centre and a large restaurant, the Kitamba Kafe. The dual goal is to create a “total immersion” experience for the visitors to make them feel they are in Africa, while at the same time recognizing that the essential dignity of the animals must be maintained.

TransAlta Rainforest Building

Simulating the warm, lush environment of tropical Africa, the rainforest building has a troop of western lowland gorillas as its main tenants. The gorilla area includes individual cages for keepers to observe the animals, as well as indoor and outdoor compounds. The rainforest area is 845 square metres and home to animals such as colobus monkeys, lemurs, ground boas, dwarf crocodiles, coloured fruit bats and 20 species of birds.

The structure, engineered by Earth Tech Canada, has no single 90-degree angle, but curves, flows and tilts in an organic way. The concrete walls are 200-mm thick, rising 21 metres high in some areas. Together with steel structural columns they support a fan shaped, stepping steel roof structure.

From a visitor’s point of view, the structure is meant to “disappear,” and it is often disguised or concealed. In the outdoor gorilla area the 3.6-m concrete walls are precoloured and have burlap in the forms. Between the gorillas and the public the glass is 38-mm thick, consisting of three layers laminated together.

The expansive glass walls and kalwal roof in the rainforest area allow the animals and plants to benefit from abundant natural light, while the roof’s translucent panels prevent high heat gains in summer. With the contrast between climatic conditions inside and outside, the connections between glass, concrete and roof had to be carefully designed.

The indoor temperature is maintained at 68F and humidity levels at 80% — this in a climate that can have temperature swings of up to 45F in a 24-hour period. Keen Engineering were the mechanical engineers and used environmental approaches for the water, heating and cooling systems, making use of nearby ground wells. Water extracted from the wells is used for mist that cools and humidifies the rainforest. The well water also supplies the air-handling unit cooling coils, then is diverted into the building’s 59,000-litre cistern, or into an injection well if the cistern is full. The cistern also collects storm water which is used for irrigating the zoo’s landscaped areas.

The zoo’s main boiler plant provides hydronic heat, which is distributed as radiant surface heat to the artificial gunite and shotcrete rocks and trees. The effect is to simulate the heat of the sun and allow the animals to use the outdoor spaces in spring and fall. The boa area, for example, has hot water slab heating inside an artificial tree. Weaving throughout the space are streams, ponds and waterfalls, individually controlled and kept pristine by biofilters, drum filters and ultra-violet treatment. Each piece of critical equipment is connected to the building management network.

African Savannah

Another largely glass structure was built to house animals that occupy the African veld, such as giraffes, zebras, warthogs, vultures and hippos. One whole side of the building was designed to open up to create a vista view, using a large 10-m x 30-m hangar door. A baobab tree structure houses mechanical equipment and zoo-keeper space.

A 360,000-litre hippo pool, 2.5 metres deep, is a main feature. It has a curved underwater glazed viewing area to allow visitors to watch the animals, and the water is kept clear of hippo feces and in constant motion by water inlets and outlet skimmers that scour the floor and skim the surface. Return water from the pool is filtered through steel mesh gross filtering, then a series of sand filters. Heat and pH levels are adjusted and ozone is added for bacterial control. The system changes the water in the pool every 30-45 minutes. The giraffe area has sloped floors and non-porous walls, convenient for drainage when the animals are washed down. and the floors have radiant heat and special rubberized surfaces for warmth.

Destination Africa opened in January 2003 as the largest facility ever developed at the Calgary Zoo. It was completed on time and budget. One weekend last summer it had a record 40,000 visitors. With 101 species of animals, and 80 species of rare plants, the facility is a learning centre, a recreational escape and an oasis for endangered animals. The TransAlta building received the American Concrete Association 2003 Award of Excellence. — BP

Client: Calgary Zoological Society

Architect: BKDI Architects

Structural: Earth Tech Canada

Mechanical: Keen Engineering

Electrical: Stebnicki Robertson & Associates

Building envelope: Building Envelope Engineering

Landscape: Calgary Zoo and Matrix Landscape Architecture

Contractor: PCL Maxam


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