Standards for earthquake resistance

Safer buildings

Issue: The promotion of wood as a renewable, affordable material for building houses and larger structures in earthquake-prone zones depends on sound standards for earthquake-resistant designs.

Solution: Canadian scientists have researched the behaviour of wood buildings in earthquakes and have contributed to evolving design standards and codes.

Earthquake damaged building. Conception, Chile

Earthquake damaged building. Conception, Chile

Scientists with FPInnovations have studied the earthquake (seismic) resistance of wood buildings for at least two decades. Their research shows that wood-frame structures can withstand earthquakes without collapsing, making wood an excellent—and safe—choice for building in earthquake regions.

Researchers have also pinpointed features that may reduce the seismic resistance of wood buildings. For example, if there’s a large opening in the first-storey wall, to accommodate a garage or a large window, the building may be less able to withstand earthquake loads unless it’s designed to take the opening into account. That’s where seismic standards come into play.

Seismic standards

In Canada, building codes and wood design standards specify how to design buildings that can withstand earthquakes. Ensuring that these codes and standards are science-based and up to date is a priority, particularly in British Columbia and Quebec, the provinces with the highest seismic risk.

Research by FPInnovations scientists has contributed to building standards, codes and design tools in many ways:

Earthquake simulation tests. Photo: NEESWood Project

Earthquake simulation tests. Photo: NEESWood Project

  • helped tailor the seismic provisions under the Canadian standard for engineering design in wood (known as CSA O86)
  • supported revisions in the 2010 National Building Code, including changes to Part 9 (wood construction of houses and small buildings) and Part 4 (engineered buildings) that allow wood to be used for constructing larger buildings
  • influenced changes to the B.C. Building Code that increased the maximum allowable height of wood-frame residential buildings from four storeys to six
  • developed, with the University of British Columbia, a new “midply” shear wall system that can bear two to three times the lateral load of a conventional shear wall
  • helped develop computer models that simulate how wood buildings perform under different earthquake conditions

International influence

Research on the seismic performance of wood buildings doesn’t just help wood construction in Canada. It’s also valuable for other earthquake-prone countries that are developing building standards. Japan, most of which is in a high-risk earthquake zone, began adopting North American–style wood construction several decades ago. China is now following suit.

The need for better design standards and improved construction was tragically illustrated in January 2010, when a devastating earthquake hit Haiti, claiming more than 200 000 lives and leaving a million people homeless. In contrast, the more powerful quake that rocked Chile the next month brought a far lower death toll. Better building codes and construction practices have been cited as reasons for the difference.

In May 2008, an earthquake measuring 8.0 on the Richter scale devastated southwest China’s Sichuan province. The quake claimed close to 90,000 lives, displaced 5 million people and destroyed hundreds of thousands of buildings.

Xiang’e Primary School in Dujiangyan. Photo: FII China

Xiang’e Primary School in Dujiangyan. Photo: FII China

Soon after, the governments of Canada and British Columbia provided $8 million to help replace public buildings destroyed in the quake. Canada’s contribution ($3 million) came through NRCan’s Canada Wood Export Program. The project involved the use of Canadian-style wood frame construction and Canadian wood products.

The first building completed under the project was the Xiang’e Primary School in Dujiangyan. The 5,300-square-metre facility, which includes classrooms, dorms and common areas, is the first wood-frame school in China. In September 2009, it opened its doors to nearly 400 students.

Construction of the school involved collaboration between Canada and China. Experts from B.C.’s Forestry Innovation Investment, the province’s international marketing agency for forest products, and the Canada Wood Group, a consortium of Canadian forest product associations, worked closely with Chinese officials from the Shanghai Reconstruction Committee and Tongji University.

“Canada Wood is honoured to have been involved in bringing a new, safe learning environment to the community and to the students of Xiang’e,” said Fred Spoke, Managing Director of the Canada Wood Group in China.