Field Demonstration Projects
Ontario

Chatham Bridge

In cooperation with ISIS Canada, the Ontario Ministry of Transportation has rehabilitated the Chatham Bridge crossing Highway 401 to include the world's second steel free concrete deck slab. (The first, the Salmon River Bridge in Nova Scotia, is also a Canadian achievement.) The two outer spans of the four-span bridge each have a 175-mm thick, steel free deck slab which is transversely confined with steel straps welded to the top flanges of the steel girders.

The cantilever portions of the deck slab are reinforced by a NEFMAC grid of carbon fibre reinforced polymer. With no steel inside the bridge deck to corrode, the concrete is immune to the damaging effects of chlorides. For engineers, this revolutionizes the way bridges are designed because it means that a relatively thin concrete slab can span a long distance without embedded reinforcement. This, is turn, means that bridge decks can be virtually maintenance-free. The steel-free deck has won five national and international awards.

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Leslie Street Bridge

The Ontario Ministry of Transportation had originally scheduled conventional concrete column repairs for the Leslie Street Bridge in Toronto, but then decided to experiment with fibre reinforced polymer (FRP) wraps instrumented with fibre optic strain sensors. The concrete columns supporting the bridge now possess two unique features: four columns are wrapped to a height of approximately 3-m with carbon FRP, and two of the columns are instrumented with the first experimental long gauge fibre optic sensors ever manufactured or field tested in Canada. While most fibre optic sensors are 3 to 4-cm long and provide temperature readings and defined points of strain, the Leslie Street Bridge sensors are one-of-a-kind, custom-made sensors with a length equal to the circumference of the column, which could be several metres. Researchers record displacement of any kind. Expanded columns indicate the interior steel is corroding. If there is no expansion, the FRP wraps have done their job in halting corrosion.

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Bridge Girders in the Region of Waterloo

This project focuses on the serviceability and durability of FRP repair systems for reinforced concrete beams in a bridge in the Region of Waterloo that is subjected to aggressive corrosive environments and service loads. This project is the first large-scale field application for using advanced materials to effectively rehabilitate concrete flexural members with steel reinforcement corrosion in Ontario. The cost savings are potentially enormous in the Canadian climate, where de-icing salts are used extensively and lead to rapid corrosion damage of infrastructure systems.

FRP repair systems will provide significant benefits including increased service life of the bridge structure and decreased negative environmental impact, since the bridge is over a river. The RC beams show signs of corrosion damage through longitudinal cracking and some delamination.  Previous crack repairs proved inefficient and alternative repair schemes are required. The beams will be repaired by externally epoxy-bonding FRP sheets to the concrete surface, and the performance of the FRP repair will be monitored over time. Monitoring will be performed using conventional strain gauges as well as fibre optic sensors. The data collected will be useful for service life prediction models for FRP repair systems of corrosion damaged reinforced concrete beams.

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