Endangered Māori construction techniques that have been proven to be able to withstand major earthquakes will be used to rebuild a historic Bay of Plenty wharenui.
Architect and researcher Professor Anthony Hoete and his team from Auckland University showed this by using endangered construction knowledge calledmīmiro to create a full-scale timber structure, and successfully tested the prototype against earthquake requirements for modern buildings.
Mīmiro involves the use of interlocking structure supports, with rope used to lash the supports together before tightening them to strengthen the building.
Hoete, a professor of architecture and planning at Auckland University, told Morning Report he has been impressed with the results.
“It’s been quite amazing — we’ve been on site and we’ve been literally pulling the structure using jeeps and winches and getting up to 3 tonnes of lateral load, and then we do a snap test, let the cables go, and you get to see the building structure oscillate for up to about nine seconds,” Hoete said.
Auckland professor and Māori architectonic researcher Dr Jeremy Treadwell designed and built the timber portals by using interlocking compression joints, instead of bolting parts together. At the same time, ropes were used to pull the structure to the ground like a tent.
Last weekend, Hoete’s team worked with the School of Engineering to pull the vertical portals sideways and test the horizontal strength of the structure, which was tested by using a winch running off a jeep, while the vertical strength was tested using water weights.
Hoete said the team was working to revive the ancient method after it was lost when Europeans arrived in Aotearoa.
“So, you can imagine when the Europeans arrived, screws and nails turned up and all kind of manner of things, and of course, [for] Māori, who were effectively using carvings to notch in to make these sort of mortise-and-tenon joinery joints, timbers could be interlocked without fixing.
“And of course, that practice has become increasingly endangered — interlocking timber structures are then pulled back down to the ground with post-tensioning. That’s what will be harakeke or muka flax, but today, we’re using other materials more commonly available,” Hoete said.
Trucks were used to create the effect of an earthquake on the structure.
“Post-tensioning, you basically build these compression elements, and you can literally crank up the tensions so you can stiffen the structure, so the structure could be more respondent after an earthquake.”
The team has been working closely with Ngāti Ira o Waioweka, who built the original Tānewhirinaki wharenui near Opōtiki after the 1860 New Zealand Wars.
More than 70 years later, in 1931, it was destroyed by a 7.8-magnitude earthquake in Hawke’s Bay.
Restoration project leader Riki Kurei (Ngāti Ira) said he has been working on restoration since 2010, and was thrilled with how far the project had come.
Senior Māori research adviser Toka Tū Ake Hema Wihongi said this was the type of important knowledge and research the organisation wanted to contribute towards.
“Toka Tū Ake is interested in investing in mātauranga Māori. We have $19 million we use every year for all sorts of research to protect communities against natural hazards.
“This project is important because it was one of the marae that was destroyed during the Napier earthquake, and it also aligns with Toka Tu Ake’s objectives: supporting Māori and building their community resilience,” Wihongi said.
