Bridge to the Future

A new bridge at Portneuf, Quebec, has been designed and built using concrete that offers greater strength and durability than ever before, thanks to a Canadian Network's leading-edge research in high-performance concrete (HPC). The bridge, which replaces an old steel bridge in the heart of Portneuf, is the first of its kind in North America to be designed and built out of HPC, using the technology developed by the Network of Centres of Excellence on High-performance Concrete. HPC's high durability and strength makes it ideal for thinner structural designs. This proved to be the best solution for constructing the Portneuf bridge within certain space limitations and other physical restrictions: the bridge had to be built across a small river that could rise fairly high owing to a tide and spring thaw. A thinner deck would help avoid the rising water. "Without high-performance concrete technology, we could not have constructed this type of bridge," says Louis-George Coulombe, a structural engineer with the Quebec Ministry of Transportation.

This successful project is the outcome of a unique partnership involving the Network and over 20 building contractors, consulting engineers, materials companies, owners and researchers in Quebec. They have linked up in a technology transfer endeavour called 'Projet Voles Nouvelles du Béton,' aimed at finding and developing new applications for high-performance concrete. According to Francois Lacroix, Director of 'Projet Voles Nouvelles du Béton,' and the Quebec Regional Director of the Canadian Portland Cement Association, "the existence of the Network of Centres of Excellence on High-performance Concrete is what got 'Projet Voles Nouvelles du Béton' under way in 1990. Our aim is to increase the application of HPC and have experimental projects built to make its use commonplace." After their success with the Portneuf bridge, the partners are working together to develop specifications for other HPC projects, including a bridge at Mirabel, and pedestrian overpasses in Laval.

The Network, which offered its expertise and technology in developing the material for the Portneuf bridge, has installed sophisticated measuring instruments in the bridge to gather crucial data for further research.

The bridge's entire structure, including the deck, is made of 60-MPa silica-fume concrete (MPa, or Megapascal, is the measurement for the compressive strength of concrete). It has been built to withstand all types of traffic, including heavy machinery and trucks. Extra protective materials such as membrane and asphalt on the deck have been eliminated to confirm research results on the strong performance of HPC under traffic conditions. Eliminating the need for protective materials could help lower costs for repairing and replacing Canada's costly infrastructure, and the durability of HPC will help lower the maintenance cost over the life of the new structure. In Quebec alone, at least $300 million will be spent on replacing or reinforcing older bridges in the next 10 years.

For more information please visit the Concrete Canada Web site.