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More than 50 structural engineers, geotech experts and architects will thrash out how Christchurch can rebuild on its soft land at an international workshop next Monday.
The event has been organised by the Peterborough Village committee and there will be a public feedback session at the Knox Centre in Christchurch at 7.30pm. Peterborough is the first community village to be formed inside Christchurch’s quake-battered central city. The business and residential precinct includes Colombo, Salisbury and Barbadoes Sts through to the Avon River.
Organiser Di Lucas said Christchurch’s central city and TC3 (green-blue zones) areas can be rebuilt by placing new structures lightly on the land.
``Some people say our TC3 (green-blue) zones should be red zoned. But they are buildable. This workshop will show various ways for how it can be done, and done affordably,’’ Lucas said today.
``Building lighter structures with timber is good in using local materials and for our carbon footprint. Lighter structures also allow for re-levelable floors so they can be adjusted if we get another big one (earthquake).
``We’ll get the experts at the workshop to evaluate the different scenarios, identify advantages and limitations, and come up with systems with greatest applicability for development on this soft ground.’’
Among those investigating particular sites and presenting options are Wellington structural engineer Alistair Cattanach, Auckland timber construction expert Mark Batchelar, Christchurch geotech specialist Nick Traylen and Christchurch architect Thom Craig. Several overseas experts will contribute, some attending, and others presenting by video-link.
Lucas said she wanted Peterborough Village to be innovative, not just on how it was built, but in its character, how it projected a confidence in responsibly addressing these lands. She said engineers and architects are working to formulate scenarios that in total are a design response to this soft ground.
``We understand there are 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 concrete piles, Lucas said.
’’With gravels buried five to 20 metres below ground level, it is appropriate that other methods are explored. In much of the central city and TC3 areas the cost of stronger and deeper foundations under post-quake by-laws could be unaffordable for some people. Alternative construction methods need to be explored.
``That’s why we are running this workshop to get alternative designs, alternative ways to build on soft ground. We want the village to be a cutting edge, innovative hub for redevelopment with the focus on affordable resilience and sustainability.
``Rather than just design a re-build and then wonder how it can be supported from the top down, the workshop will explore ways to creatively and safely respond to the soft ground from the bottom up.’’
And rather than the Venice model, with stone buildings sitting on timber piles in water, that appear to ignore what’s below, or the standard here of designing a tilt slab building and then trying to work out how to support it, Lucas said she would like to have buildings designed as responding to, and emerging from, out soft ground.
The Peterborough village precinct has traditionally been, and is intended to remain, half commercial and half residential, but it is hugely damaged. Most blocks will soon have scarcely a building remaining. This provides great opportunity for innovative redevelopment.
See the TC3 map http://www.peterboroughvillage.org.nz/geotech-information/