The Tourand Creek Bridge - Manitoba - Winnipeg

Timber Bridges in Manitoba

• 575 bridges were built prior to 1980.
• Province estimates it will cost $260 million to replace bridges that can no longer withstand current legally allowed weights.
• If the bridges are strengthened using glass FRP technology, the cost will be just 15 percent of that required to replace the structures.
• FRP bars do not add significant weight to the structure.

The Tourand Creek Bridge south of Winnipeg on highway 59 has been selected as the first of its kind to undergo an innovative strengthening technique developed by ISIS Canada. Upon completion, this 39-year-old structure will be at least 30 percent stronger. Manitoba Highways and Government Services has committed $110,000 to test the new technology, anticipating it will be suitable for extending the service life of similar bridges.

The province has 575 timber bridges all of which were built prior to 1980 and require strengthening in order to accommodate the increased traffic loads permitted by the Transportation Association of Canada (TAC Loads). Manitoba Highways and Government Services has estimated that replacing the Province. s aging structures would require an investment of approximately $260 million. It estimates it will cost $90 million to replace the 170 treated timber bridges on the Provincial Trunk highway system and $170 million to replace the remaining 405 treated timber bridges with new bridges. However, by using the simple, innovative strengthening technique whereby glass fibre reinforced polymer (FRP) bars are embedded longitudinally in the stringers and adhered to the wood beam grooves with an epoxy resin, bridges like the Tourand Creek bridge can achieve the same strength as a new structure for less than 15 percent of the $800,000 estimated to completely replace the bridge.

The cost to strengthen each stringer with glass FRP bars is $1,500. The benefits of using glass FRP bars are that they do not add significant weight to the structure and do not corrode when exposed to road salt.

For contractors like Joe Solomon, C.E.T. . President of concrete Restoration Services Ltd., who is working on the Tourand Creek bridge project, FRPs provide a convenient alternative to conventional strengthening techniques. . The material is easy to work with, offering such benefits as being non-corrosive. In addition, no heavy equipment is required to install the FRP reinforcement because it is lightweight. Joe Solomon said, "It can be installed with virtually no obstructions, disturbances or inconvenience to the travelling public."

Dr. Sami Rizkalla, President of ISIS Canada and Professor of Civil Engineering at the University of Manitoba explains that the Tourand Creek bridge is an unprecedented strengthening project. However, it is by no means an experimental exercise. . The experimental program was completed much earlier in the McQuade Structures Laboratory at the University of Manitoba. Tests proved that glass FRP bars are a feasible solution for strengthening timber bridges. Rizkalla said, "Ductility is dramatically improved and the flexural strength can be increased by 20 to 50 percent."

Twenty-two beams were tested to determine the predictable behaviour of full-scale and half-scale creosote treated beams strengthened using glass FRPs. In applying the test results to the field application. The three-span 23.3-m-long Tourand Creek bridge is a particularly useful example of how FRPs can be used to strengthen wood bridges. Its design incorporates two standard stringer sizes used in most timber bridges (two 6.4-m approach spans and one 10.06-m centre span). ISIS Canada will monitor the bridges behaviour to confirm its research.

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