News and events
Wood cuts it – first of its kind using laminated veneer technology
It stands proud and strong amid a row of empty sections and damaged, snaggle-toothed edifices on the changing sidelines of Victoria St.
No 134, this three-storey building under construction, with its standout wooden superstructure, is a signpost to a fresh future, a flag for sustainable progress, and a forward marker for the shape of things to come for our fracture zone on the Canterbury Plains.
Due to be finished mid-year, the Tony Merritt-owned commercial building will feature open-plan office space and sculptural internal detailing. Its timber skeleton will be evident through its glass frontage and north-facing side wall. The engineers, developers and architects – everyone involved in its planning and construction – want it to be seen for what it is: an elegant, earthquake-resistant, multi-storey building. Built using high- strength, laminated veneer lumber (LVL) technology developed at Canterbury University, the building fits the parameters many have called for in the rebuild of Christchurch: it’s human scale, it will look good, it’s safe and made to last.
The concept was designed by architect Jasper van der Lingen, a director at Sheppard & Rout Architects, with engineering by Kirk Roberts Consulting Engineers.
“The architectural intention is to try to show off the timber and also the post- tensioned earthquake-resisting technology,” van der Lingen says. “There are cables that run horizontally through the building and they’ve got end caps, which will be left. There are also what they call energy dissipators at the junctions, which are there to take up the energy if an earthquake shakes up the building. All that will be exposed as part of the look.
“It was designed not long after the quakes in the midst of big aftershocks,” he says.
“There was a sense then, which I think is slightly mellowing now as time goes on, that a building had to be very obviously strong, robust and resilient.”
While these were major factors in the design, there was no need to compromise on aesthetic appeal.
“The stair lobby, halfway down the building, is triple-height space – we’ve tried to get a bit of drama there – and we’ve got open stairs. So instead of walking through a door into a fire- rated stairwell, through design we’ve managed to keep the stairwell open and we’ll clad it in timber.”
The building required a concrete wall on its southern boundary side, and this wall has been cast on timber boards to imprint it with knots and grains and continue the timber “look”.
“Inside we’re trying to keep it as open as possible – the last thing we want is a lot of little cubicle offices with GIB board – so you’ll be able to see in and get that big space with the timber beams and columns.
“It’s what the client agreed to. There’s a degree of conservatism when people are spending millions on a building, trying things that have never been done – except for Tony Merritt. When he came to me, he said, ‘I’d like to do a timber building’, so it was a match made in heaven. There was synergy there.”
The nub of the matter is the innovative timber componentry and earthquake- resistant construction technology that form the bones of the structure. This can be applied to single or medium-rise multi-storey buildings and large-span structures using timber framework. It was developed at the University of Canterbury by the Structural Innovation Timber Company (STIC), a government- backed research and development company, comprising academic and industry shareholders: Carter Holt Harvey, Nelson Pine Industries, Wesbeam, Building Research Association New Zealand, NZ Pine Manufacturers Association, Auckland Uniservices and the University of Canterbury. Other investors are the Foundation for Research Science and Technology as well as Forest and Wood Products Australia. (See also Solid as a Wooden Rock, YW, September 2011.) With five years of government funding (due to expire in June), STIC was tasked with developing innovative and commercially viable ways of using timber in the building industry.
The key personnel include Dr Stefano Pampanin, Canterbury University’s associate professor of civil and natural resources engineering, and Dr Andy Buchanan, research director at STIC and professor of timber design at the university. Both men have specific interests in seismic design philosophy and earthquake engineering.
What their research teams came up with were earthquake-resistant building solutions using New Zealand-grown radiata pine: pre-fabricated and glue- laminated wall sections, box beams and solid columns. In construction, these timber parts are threaded through with high-tensile steel cables or tendons and shock-absorbing steel componentry that enable a building to essentially pull itself back into alignment after a major shake.
“It was a whole philosophical change from the way buildings were done pre- quake,” van der Lingen says. “The codes were designed for people-safety first and they didn’t care so much about the buildings. Now, because of our experiences here, we realise it’s incredibly disruptive, so unsustainable and so wrong in many ways, and it’s better if we design buildings, both to get people out safely and so that they are repairable afterwards.
“The cables can pull it back into shape or, if you have to, you can tension it back up. Those little energy dissipators are sacrificial in a really major quake (hopefully we won’t have a really major quake again), and they could be unbolted and replaced.”
The hi-tech timber components are manufactured by Carter Holt Harvey at Marsden Point in Whangarei and Nelson Pine Industries in Nelson. The use of timber technology as opposed to concrete means that a building can be lighter and thus more economically viable, in that it requires less foundation work. Timber is also flexible, grown locally, and has a higher strength-to- weight ratio than concrete.
It’s a building system that is smart, modern, ecologically sound and local. We grow it, we make it, we design it, we build it. It’s sustainable, it’s exportable. It has to be good for New Zealand Inc in the longterm.
Robert Finch is STIC’s chief executive. “STIC was set up to carry out a research and development programme and promulgate the outputs of that R&D programme to the key industry design professionals on both sides of the Tasman, particularly architects and engineers, and to some extent quantity surveyors and contractors,” he says.
“We’ve had a huge amount of interest and it’s been steadily growing. The interest has been broadly based, from the design professionals through to politicians, local government and other academics interested in timber research techniques, as well as contractors and whatnot.”
So far there are eight completed New Zealand buildings using STIC- developed technology, including the award-winning Arts & Media building at the Nelson Marlborough Institute of Technology and another three-storey building on the Massey University campus. “Not very many,” Finch says, “but it’s a good start, considering that we’ve been in the middle of a research programme.”
Three are under construction in Christchurch (although one of these is on hold while decisions are made about its main contractor, Mainzeal) and another three are in advanced stages of design. A further half-dozen are under consideration.
The tallest of those under way is the five-storey building on the corner of Montreal and Hereford streets. This replaces the historic 1930 apartment building, St Elmo Courts, which was demolished after the earthquakes.
“The beams and the frames are post- tensioned LVL, but for various reasons the designers chose to use concrete columns, so it’s a real composite of concrete and timber, with some steel. It’s also been put on base isolation, so it’s a combination of damage-avoidance rocking systems and the more traditional base-isolation technique used by Christchurch Women’s Hospital.”
Until now, STIC’s two-storey demonstration building, purpose built at the Engineering Department’s grounds at Ilam as a show-and-tell facility, has been STIC headquarters, where Finch is based. “Over the past couple of years we’ve literally had hundreds of visitors coming here . . . a number of the key property owners and developers from the Christchurch CBD, including Ngai Tahu. Pretty much all of them go away excited about the opportunity offered by engineered timber, and a sense that they’d never recognised timber could be used in this way in their multi-storey buildings.”
The test building also houses sensitive seismic recording instrumentation, which has collected invaluable data since the major quake of February 22. The test building’s future is undecided, but increasing interest in the results of STIC’s R&D programme indicate the need for a continuation of this cross- Tasman venture after the completion of its government remit in June.
Finch says: “It’s pretty obvious that we’ve evolved and developed a second role, which is one of assisting and demonstration, and beyond that, with the help of the university, providing early technical assistance at preliminary design stage for the engineers and the architects. The system is new and it’s not immediately apparent how to apply it.”
In the meantime, the building at 134 Victoria St is attracting interest from industry professionals as well as the public. On the day we talked to the architect, 50 people from the New Zealand Institute of Building had been shown through. Others to view it have been engineers, people involved in forestry and timber technology, and Nathan Guy, the Minister for Primary Industries. “It’s such a good-news story in many ways because it uses radiata pine, which is grown in New Zealand,” says van der Lingen.
“This is normally not always the highest grade timber, but by engineering it into this laminated system, it is turned into a high-grade timber. It’s grown here, fabricated here, erected here by local people. And wood is carbon-capture and renewable. It’s about as sustainable as you can get.
“There’s a lot of talk about how New Zealand exports raw logs, which go to other countries, who turn it into a valuable product – furniture, houses and so on. It seems such a waste. This is something, that, if we get it right, it’s got so many good sides to it. Instead of just exporting raw logs we could export beams and columns, which have been manufactured with expertise here. It’s a very good news story.”
– © Fairfax NZ News
courtesy of stuff.co.nz – view original story here – http://www.stuff.co.nz/the-press/business/the-rebuild/8465000/Wood-cuts-it
26 March 2013