Cutting edge seismic-resistance techniques have helped a New Zealand/Italian alliance win a prestigious urban village design competition as part of the Christchurch earthquake reconstruction process.
The unique competition issued a challenge internationally for teams around the world to come up with a financially viable benchmark design for 21st century inner city living which offers an exceptional quality of life.
The entry from a team led by New Zealand locals Holloway Builders with architects Anselmi Attiani Architettura and engineers Cresco, both from Italy, was hailed by judges as well-designed and structurally innovative, as well as an affordable and sustainable option.
The innovative technologies are colourfully known as Armadillo and Seismat.
“The Armadillo is a re-levelable slab,” said Fabio Parodi of Cresco. “That is to say that after a major seismic event and in case of settlements, the levels of a house equipped with this foundation system can be restored without significant works in a short period of time. In fact, it can be done in less than one week.”
Paradi stumbled upon the idea after visiting Christchurch and discovering that builders still use polystyrene pods to lighten foundation slabs. He realized there would be benefits to introducing stackable pods that don't require as much space and that don't move away with the slightest breath of wind.
The only other possible solution to overcome the problem of the subsiding of liquefiable soils is a complex and expensive method using two slabs with pre-installed jacks.
Armadillo is a cost effective, clever and speedy construction system capable of delivering high strength and able to withstand re-levelling by jacking just around the perimeter of foundation. Focussing on the perimeter is the key to eliminating unnecessary over-engineering and removing the cost of lifting.
Using an eco-friendly material for the formworks, the Holloway team was able to introduce for the first time a slab that combines internal air ventilation with flexible strength.
The Seismat solution, meanwhile, is a passive load transfer device that reduces the costs to a base isolation (necessary with conventional seismic supports) because it generates a zero friction layer between two concrete casts.
“The coupled laminated panels reduce thickness in controlled time under the pressure of the wet concrete and they progressively drive the vertical loads only to specific bearing points eliminating the expense and time consuming process of creating suspension bespoke formworks,” Parodi explained.
Innovative Pres-Lam construction engineering technology - developed in New Zealand - is also being considered as part of the light-weight, sustainable structural solution.
Christchurch Mayor Elect Lianne Dalziel said the competition had energised thinking with respect to central city residential construction.
“The winning design is hugely exciting and an example of the innovation and opportunities the Christchurch rebuild is generating. It is also a tribute to the high standard of the finalists that elements of each could be picked up for the Christchurch rebuild,” she said.
UK Grand Design host and international judge Kevin McCloud was equally effusive in his praise.
“This is a well-considered and mature scheme that builds on a vernacular of timber dwellings in the area," he said. "It imports some of the more progressive international ideas in public realm design.”
The competition attracted major international interest with 58 valid entries received from 15 countries.
The Holloway team will now begin the detailed design phase on the 8,149 square metre central Christchurch site and, subject to financing, construction work on the development is expected to begin in the second half of 2014.