While wood products aren’t always front-of-mind in the engineering sector, research from the University of Canterbury’s Structural Engineering Laboratory has demonstrated that cross-laminated timber (CLT) walls are feasible, cost-competitive, and sustainable alternative in low-rise buildings.
Associate Professor Minghao Li and his PhD student Ben Moerman have been testing large CLT shear walls in the laboratory to find out how these multi-storey walls behave in significant earthquakes – and their findings could have “far reaching implications” for the industry, as well as New Zealand’s quest to become a carbon-neutral economy.
One-fifth the weight of concreate, the walls were “loaded horizontally to create a similar scenario of multi-storey CLT buildings in big earthquakes like the ones in Christchurch,” explains Li.
“With the right connections, CLT buildings can be really strong and resilient in an earthquake.”
The research team designed innovative high-capacity connections to resist earthquake forces and protect the integrity of the timber walls. Steel dowels in the connections bend to absorb energy and prevent the walls from being significantly damaged or collapsing.
“The main benefit is that after an earthquake you can simply replace the dowels and the buildings will be just as strong as they were before the earthquake,” says Moerman.
It is also hoped that the EQC-funded research in Christchurch will have major environmental implications.
“If we can put more wood from sustainable plantations into buildings, we can lock carbon into those buildings for at least 50 years, which will have great benefits for New Zealand to achieve our carbon-neutral goals,” says Li.
While Li acknowledges that currently engineered timber materials might be slightly more expensive than other materials, the speed of construction and limited resources required may also make timber a cost-competitive solution.
Image credit: University of Canterbury