Managing Wisconsin's Freight System by Rehabilitation and Strengthening of Timber Bridges with Composite Materials

The objective of this project is to develop new techniques using mechanically-fastened fiber reinforced polymer (MF-FRP) composite materials for rehabilitation and strengthening of timber railroad bridges. The Wisconsin Department of Transportation (WisDOT) Bureau of Rails and Harbors owns numerous timber railroad bridges. These bridges are leased to regional railroad companies. Most of these bridges were constructed between 1900 and 1965 and are in need of rehabilitation to extend their service lives and need strengthening to increase their load carrying capacities due to recent increases in rail car weights. It is estimated that $24.7 million will be need in the next five year to rehabilitate timber railroad bridges in Wisconsin. The research will investigate alternative, and potentially more economical, methods of rehabilitating and repairing railroad timber trestle bridges using fiber reinforced polymer (FRP) composite materials. The work will be conducted in collaboration with researchers at the USDA Forest Products Laboratory (FPL). Specifically, the research will develop techniques for strengthening and stiffening timber cap beams, which are the most problematic members in these bridges. The FRP materials will be mechanically fastened to the timber beams using a method previously developed at the University of Wisconsin. Static and dynamic tests will be conducted at the FPL and recommendations will be made for field implementation of the method.