Civil engineers from the University of Canterbury have created Christchurch's first multi-storey post-earthquake timber building using low-damage post-tensioned timber technology.
Civil engineering professors Andy Buchanan and Stefano Pampanin, with support from senior lecturer Dr Alessandro Palermo, began their research before the earthquakes in 2010 and 2011. This led to the idea of pre-fabricated and glue-laminated box beams and solid columns.
Architecture firm Sheppard & Rout and structural engineering consultancy Kirk Roberts took this concept and integrated it into their designs for the multi-storey office development, the Merritt building, which is the first earthquake-resilient open-plan timber building to be part of Christchurch’s rebuild, as well as the first commercial building of its kind in New Zealand.
The timber is threaded with high-tensile steel tendons and shock-absorbing steel components that enable the building to essentially spring back into alignment following a major quake.
The architects and engineers have used time history analysis, modelling the Canterbury earthquakes and other major event from around the world to come up with the Merritt building’s final design. Analysis has demonstrated that the building will be able to resist a 1/2500 year event seismic event, well above the performance of a normal structure.
Using new energy-dissipating low-damage technologies, the building has been able to achieve a capacity and performance over two times the building code level without any of the additional structural costs needed for an equivalent normal office building.
Another large post-quake building, for Trimble Navigation, officially opens in Christchurch on April 4.
The Trimble building uses the same post-tensioned timber technology. Although it stand only two storeys high, it covers a much larger area. It will contain all the latest Trimble technology for monitoring building performance.
A third similar project is being built in Kaikoura for the Kaikoura District Council. The three-storey building, made entirely of wood above concrete foundations, will contain a museum, library and council offices. It uses post-tensioned rocking timber walls for low-damage earthquake resistance.
The work of the University of Canterbury engineers has seen the increased use of timber as a structural material, according to College of Engineering pro-vice chancellor, professor Jan Evans-Freeman, with new multi-storey timber buildings of up to 10 levels being built in Europe, North America and Australia, as well as proposals for a 30-storey timber building on the drawing board in Canada.
“Their pioneering research has lifted engineered timber buildings into serious contention for the Christchurch rebuild after the 2010 and 2011 earthquakes,” said Evans-Freeman.