Earthquake research ensures it’s as safe as houses

22 May 2006

Earthquake research ensures it’s as safe as houses

A new home build by Habitat for Humanity has the added bonus of being one of New Zealand’s most earthquake resistant houses, thanks to the engineering skills of a University of Auckland PhD student.

Gavin Wight is helping to build the house with the help of his PhD research, resulting in stronger walls that stand the test of earthquakes.

The six-member Marsters family from South Auckland will be the owners of the new Clendon property.

Gavin recently completed his PhD through the Faculty of Engineering’s Department of Civil and Environmental Engineering. He decided to work with Habitat for Humanity because of the worthy nature of its cause: to build affordable homes for low income families.

“I approached Habitat for Humanity because it is a great cause and they were excited about including innovative building practices in their homes,” says Gavin.

“My research demonstrated the improved earthquake performance that can be obtained by post-tensioning the masonry walls. This house represents the first post-tensioned masonry house worldwide to be designed and built to current seismic requirements.”

The improved concrete masonry walls contain high strength steel coated in plastic so that the steel is not bound to the concrete in the masonry walls. The steel is then stressed or stretched during a process called post-tensioning.

“The steel remains stressed within the wall, compressing the masonry and providing wall strength,” says Gavin.

During an earthquake, this type of wall will rock and return to its original vertical position after the event. Walls built using post-tensioning will sustain less damage and be easier to repair.

Gavin conducted much of his laboratory research at North Carolina State University after spending 18 months there on a Fulbright exchange.

“I built a number of different walls and subjected them to real earthquakes using a shake table, to determine how each wall would perform,” says Gavin.

The Marsters will move into their new four-bedroom home in early June.

-ENDS-

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