Ravenscar House in Christchurch is a single storey structure whose external walls and roof are made from textured pre-cast concrete (aggregate from recycled demolition materials from buildings damaged in the Canterbury earthquakes).

 

The client wanted a lasting legacy so we designed the building to a higher standard than that required by the Building Code.

 

Benefits of having us on the team:

 

• The ground floor sits on base isolators designed to absorb an earthquake’s energy and limit forces on the structure. The lift and stairs have been designed to hang from the ground-floorstructure to allow for movement where the base isolators are.

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• The basement has been designed with an 800mm thick concrete slab that encapsulates all drainage services to prevent them from being damaged in the event of an earthquake.Groundwater levels in Christchurch are uncertain following the 2010/2011 quakes, so the building needed a heavy slab that would withstand hydrostatic pressures (i.e. prevent the building from floating).

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• Most building services are strapped to the superstructure above the level of base isolation to protect them from earthquake actions. They have flexible connections where they cross the plane of the base isolators.

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• The building is designed to move up to 550mm in any direction in the event of an earthquake, so we had to design outside elements including stairs and ramps to accommodate this movement.

 

• It’s unusual for a roof to have large concrete tiles as these are challenging to protect. We designed a robust mounting and bracing system which allows individual tiles to be removed if necessary for maintenance.