An architect's vision
An area of central Christchurch is pushing to open up opportunities for building lightweight structures, as a less expensive and more "sensible" way to rebuild parts of the quake-ravaged city.
Peterborough Village, a residential and commercial community inside the four avenues, is organising an international workshop to look into the issue in mid-February.
Spokeswoman Di Lucas said there were concerns the cost of stronger and deeper foundations required under post-quake bylaws could be unaffordable for some.
She understood there were options for lightweight, cheaper but robust structures to sit lightly on the soft land as alternatives to the standard heavy structures being proposed on deep vertical piles.
"With gravels buried five to 20 metres below ground level, it is appropriate that other methods are explored."
At the workshop it was hoped case studies could be done for sites on which geotech reports were available, getting experts to look at different construction options, she said.
An example of the problem was popular restaurant Valentino's, which had consent to build, but for a two-storey tilt- slab building on the site the cost of foundations would be about $300,000. "This is quite exorbitant for a 200-square- metre building."
Alternative foundation options could be less expensive, more sensible, and could be more resilient in an earthquake.
Lucas said she had spoken to structural engineers who had told her more practical and less-expensive foundation options were available.
It was necessary to look at the research and testing that had been done, including at the University of Canterbury.
The community had started talking to regulators, and more discussions were planned, Lucas said.
Peterborough Village wanted to be a cutting-edge, innovative hub for redevelopment, with a focus on affordable resilience and sustainability, Lucas said.
The village precinct had traditionally been, and intended to remain, half commercial and half residential, but was hugely damaged.
"Most blocks will soon have scarcely a building remaining.
"This provides great opportunity for innovative redevelopment."
A summary of the workshop would be published at peterboroughvillage.org.nz.
Peterborough Village is bounded by Colombo, Salisbury and Barbadoes streets and the Avon River.