Earth Sheltered Housing
Projects / Mixed use
Earth Sheltered Housing
Project information
Client: Mott MacDonald Limited
Project Date: 2013
Site Location: Christchurch, New Zealand
Project Status: Development
'Mott MacDonald is pleased to support ZEDfactory's innovative use of natural and locally available materials to provide affordable Earth Sheltered Housing with the ability to create low carbon/low-cost living using renewable energy sources in earthquake and Hurricane prone areas of the world.
Preliminary analysis supports the structural safety shell concept with specific site design to be validated based on local site and soil conditions'
- credited to Mott McDonald
Introduction
The context – Aftershocks continue to affect Christchurch. It is very difficult to fund new conventional construction within the sites affected by the previous earthquakes. There are almost no conventional construction techniques that can retain their original asset value after an earthquake has passed. It is quite possible to engineer new buildings to minimise loss of life or damage, but much harder to design structures that retain the resale value or can continue operation as a valuable income generating asset.
ZEDfactory and the team have looked at conventional earthquake resistant structures and came to the following conclusion. It is possible to build very lightweight timber structures and support them on relatively thin reinforced concrete rafts – however the rafts are likely to crack easily with substrate movement, making the structures unfit for continued occupation.
So after we visit to Christchurch to see the affected earthquake zone, we decided to develop a new kind of structure that had no foundations, and could accommodate a degree of soil heave and subsidence without permanent damage, and in a way that allows continuous occupation without significant devaluation of the asset.
New urban village site looking South-East from Armage and Madras Street corner
New urban village site looking North from Madras Street
Development
The 'low-cost earth-sheltered housing' project combines housing, private gardens, a rooftop undulating public park and covered communal areas and marketplace.
The design has been arrived at from its foundations of highly sustainable criteria, low-cost construction and a seismically safe structure.
ZEDfactory has developed a range of five different typologies and two different construction systems to suit the varying lifestyles of families, couples, and single person dwellings.
The roofs of the housing forms an undulating public park, which ensures that the best use of the land is made, whilst providing a low cost, yet unique housing typology.
Two linear glass canopies enclose a market, and food growing beds. Access is via nearby streets and individual gates from private gardens which back onto the market. Children can play inside on rainy days.
Communal allotments of garden space
Carpool
Electric vehicle charging points
Pedestrian access from streets to the covered spaces
Commercial arcade market trading
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38 tube dwellings
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4 empty tubes for connecting streets and covered markets
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12 dwellings built with traditional methods
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2,424 square meters of public gardens
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943 square meters into the covered spaces
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84 sqm for shops and cafes
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50 sqm for pavement cafe
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186 sqm for greenhouse
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623 sqm for multi-use space
Roofscape provides green corridor into the frame
Urban Hillside Concept
Rooftop greenhouses
Covered space
Black water store in case of earthquake
SUDS porous surface over eggcrate rainwater storage tank with optional reverse osmosis filtration unit to maintain water for washing and toilet flushing if street freshwater supplies disrupted.
Covered space for market, cafes, shops
The terraced homes are spaced to maximise privacy between opposing bedroom windows and create secure private gardens
Construction
The construction process is affordable, simple and relatively quick. After compacting the earth foundations, pipes are placed in their positions.
Ground works
1st-week: tubes and gabion mesh
2nd-week: pebbles and soil
5th-week: tube houses built
Steel tube
Soil
Gabion wall
Each home facilitates zero carbon personal transportation by having its own parking space with an integrated electric vehicle charging point connected to the solar array.
Future proofed for Christchurch
The construction is made from different self-supporting elements. The joints between components are not rigid. Foundations are not required, as the steel tubes rest on compacted earth, and therefore is not likely to collapse during an earthquake.
When an earthquake occurs, all the components are able to vibrate and dissipate the earthquake’s energy without breaking the joints or foundations.
As the seismic waves hit the dwellings, the gabion walls and other self-supporting elements can flex in all direction to mitigate against the earthquake’s energy without damage.
When the earthquake waves arrive, gabion walls start to vibrate.
Every self-supporting element is able to vibrate in different directions
