How it Works, by Karen Wrigglesworth
I was recently privileged to meet with Andrew Charleson, an ex-Wanganui boy who is now a structural engineer and Associate Professor at the Victoria University School of Architecture, in Wellington.
Andrew has just begun a 5-month sabbatical from his teaching commitments, with plans to further investigate his interest in finding a practical, low-tech means of strengthening the small adobe-brick houses of the Peruvian poor.
His idea is simple – cut used car tyres into narrow strips, and bind them around the houses like rubber bands to increase wall strength.
Car tyres are an inherently strong material, with a web of steel reinforcing encased in the rubber, rather like the reinforcing mesh inserted in concrete driveways and slab house foundations. And, in our throw-away society, tyres are a plentiful, low-cost and under-utilised commodity – and readily available.
A large, magnitude 7.9 earthquake struck Peru in August 2007 – the same magnitude as the recent devastating earthquake in China. In Pisco, the city closest to the epicenter, more than 80% of the adobe houses collapsed or sustained heavy damage, and over 400 people in the city were killed.
Buildings constructed of weak, unreinforced materials like concrete and adobe (earth) bricks can be a deathtrap for many when the shaking begins, even when a quake is only of moderate magnitude.
About Andrew
Born in Wanganui and educated at Durie Hill School, Wanganui Collegiate, and Canterbury University, Andrew has a Masters in Civil Engineering, specializing in earthquake engineering. (Civil engineering is more-or-less about designing things that shouldn’t move, like roads, bridges, buildings.)
He joined the Ministry of Works (MoW) before graduating, and was bonded to them for 5 years. His early working life involved bridge design, supervision of an Upper Hutt subdivision for Housing Corp (which he admits was not exactly his thing!), and structural design (making sure a building’s structure, or skeleton, is strong and secure).
Andrew says, “While I was at university, I was required to do practical summer holiday work towards my degree. I spent most of one summer helping to lay the foundations for the new Wanganui District Council buildings in Guyton St. Another year I was at Lake Pukaki, surveying for the new hydro scheme.
Then, about five years after graduating, Andrew felt called to become involved with university students in a ‘semi-pastoral’ capacity. He moved to Auckland, and stepped back from engineering for a couple of years.
When he returned to engineering two years later, it was to the same structural engineering role that he had left. “But,” he says, “it took me the entire first year to get back my confidence with the day-to-day knowledge of the profession that we take for granted. Things like the normal aggregate size for a certain situation, or the standard spacing for reinforcing rods.”
Andrew and his young family later spent two years in Indonesia, where Andrew held the position of Earthquake Engineering Advisor.
The family was in Indonesia for 2 1/2 years. Andrew says, “It was very rewarding. NZ had just provided Indonesia with a new earthquake design code, from which we helped the Indonesians to develop a code of their own.
“It was a culture shock for us, particularly with a young family. And there were health issues. But there was a strong sense of ‘calling’, as well.”
“Then, after another 5 years at the MoW back in NZ, and a total of 20 years of structural work experience, I made a conscious decision to take up a teaching opportunity at the School of Architecture. Being a structural engineer challenged my technical abilities, but I wanted to grow other aspects of my personality – through teaching, and interacting more with people.
“I have found I greatly enjoy the interaction with my students, and architects, although, because I teach a compulsory subject – structures – I have to work hard to make the subject interesting and appealing. My aim is to show students how structures is relevant to architectural design. That was the premise for my first book – to show how structural elements, like ceiling beams, can become a design feature as well as a structural necessity.”
“I have just had my second book published. It was difficult to write, but very rewarding. Now I am focusing on my Peru research. I will spend three months at Lima University, testing my tyre idea on their shaking table.
“I feel fortunate with the opportunities my work at Victoria University has brought me. I enjoy the students, I enjoy the research. And I enjoy the chance engineering gives me to make a difference.”
Karen Wrigglesworth is a local engineer and writer. You can contact her on karen@inkcom.co.nz.