[Source: www.journalofcommerce.com, April 28, 2010]
|Wooden buildings in Canada could get a lot taller as a result of work by a newly formed construction research group. A consortium of 40 researchers from nine universities across Canada called NEWBuildS has been established to focus on innovative wood products and building systems. |
The group’s main objective is to increase the use of wood products in mid-rise buildings for residential and non-residential purposes in both national and global markets.
“We are repairing a 1,000 year gap, because traditionally all tall structures were made of wood,” said Ian Smith, a professor in the faculty of forestry and environmental management at the University of New Brunswick. “Structurally, we know it can be done as high as 50 to 70 metres.”
For example, he said during the Song Dynasty in China, (960 and 1279 AD) there were numerous Buddhist pagoda towers built from wood that exceeded ten stories.
In the pre-civil war U.S., cotton mills on the east coast reached nine stories or 40-50 metres high.
“With the type of machinery that was operated in these cotton mills, it would be like having a small earthquake everyday,” said Smith, who is a team leader with NEWBuildS.
According to Smith, these types of buildings could be constructed again, if the right engineering expertise is assembled.
“My research over the past 25 years has been related to the structural use of wood,” said Chui, who was recently named the director of NEWBuildS and is also a forestry and environmental management professor at the University of New Brunswick.
“I have a background in structural engineering and can apply these skills to the design of wood buildings.”
According to Chui, more than 90 per cent of Canadian wood-based construction products are used in low-rise (up to four storey) residential buildings, with the majority of these products consumed in the U.S.
There is a need to diversify into other construction sectors, so that the economic well of the Canadian wood products industry is not so closely tied to one use.
The NEWBuildS network, which plans to operate for five years, has identified multi-storey residential and non-residential buildings, as the most accessible market for future growth of Canadian wood product markets.
“I am interested in getting wood into more demanding structural applications, which requires different techniques, said Smith.
“One of the big advantages of wood is it is lighter than reinforced concrete, but can be just as rigid with comparable thickness.”
Smith said a high-rise building constructed with a steel framework could use wood to cut down mass by two thirds.
With less mass in the air, this type of building would be cheaper to build because construction time could be cut.
The prefabricated floor panels would be manufactured off site and could be installed in hours, instead of waiting for reinforced concrete to harden.
The lighter structure would require a smaller foundation and an increased capacity to resist earthquake damage.
The researchers in the NEWBuildS network have been organized as clustered projects with the following themes:
• 1 Cross laminated timber – To generate technical information, such as design properties, product evaluation procedures and system-based uses, in support of the development of a national manufacturing industry for CLT and building applications in Canada.
• 2 Hybrid building systems – To generate technical information that leads to best practices for building codes and design standards for existing hybrid and new systems for mid-rise and non-residential buildings.
– Also to develop better tools with which structural engineers can predict the responses of existing types of hybrid buildings to structural loads.
• 3 Building systems – To develop tools for predicting the flame and smoke spread behaviour in buildings, and possible loss of structural capacities during fire.
• 4. Building systems – To develop treatment processes for wood products that enhance the structural, fire and durability performance of wood-based products.
The stakeholders in the network include the Canadian Wood Council, Canadian Home Builders Association, FPInnovations (an industrial research organization), the NRC Canadian Construction Materials Centre, consulting engineers, engineered wood product manufacturers and university researchers.