The Canadian government predicts that it will spend $74 billion to repair and maintain concrete bridges and other concrete structures across its country. Recent advances in glass fiber reinforced plastic (GFRP) research for rehabilitating parking garages and bridges are persuading the Canadian government to take a second look at the material to help expand the life of concrete structures. Reinforcing the concrete with GFRP would extend the life of the structure to 100 years or more compared to steel-reinforced concrete, which needs major restoration after 25 years.
In the past five years, several parking garages have collapsed across Canada, spurring the government to investigate new ways of reinforcing parking structures to protect against corrosion. “We have thousands, perhaps even millions of bridges and concrete structures suffering from corrosion problems in Canada,” says Dr. Brahim Benmokrane, a professor of civil engineering at the University of Sherbrooke in Quebec, Canada. “We’re convinced that using innovative FRP reinforcements will save billions of dollars per year.”
Dr. Benmokrane has been involved in researching rehabilitation techniques for parking structures since November 2008 when the second floor of an underground parking garage in Montreal collapsed, killing one resident.
Currently, many of the parking garages in Canada are constructed with steel reinforcement bars and concrete. The problem with using concrete and steel is that road salt trekked in by the cars is corrosive and causes the concrete walls to crack. Once the concrete cracks and the steel reinforcement is exposed to the salt, the steel immediately begins to corrode making the parking garage increasingly unstable.
“We wanted to replace steel bars, which we felt are not the durable material and thus cause problems. In order to do that, we would have to show to engineers and end-users that FRP is a durable material,” says Dr. Benmokrane. In order to achieve that goal, Dr. Benmokrane organized the first Conference on Durability of Fiber Reinforced Polymer Composites for Construction and Rehabilitation (CDCC) in 1998 to push for the advancement of FRP in civil structures. Since then, leaders in the field of FRP civil structure, including the American Composites Manufacturers Association’s (ACMA) Director of the Composites Growth Initiative (CGI) John Busel, have written codes and standards to increase the confidence of end-users to construct using composite materials. So far, there have been four successful meetings of the CDCC; the current focus of those meetings includes composite sustainability as well as durability.