Acknowledgements

This report was prepared with funds provided by the U.S. Department of Transportation to the Mountain-Plains Consortium. MPC universities include North Dakota State University, Colorado State University (CSU), University of Wyoming, and University of Utah.

The authors appreciate the extensive assistance of Steve Babcock during the construction, fabrication, and other aspects of the specimen preparation. CSU students Misty Butler, Elliot De Jongh, Charles Manu, Rob Suarez, and Karl Wolfswinkel Helped at various times during this study, as well. Kathryn Sednek provided the clerical assistance needed in the preparation of the report and is graciously acknowledged for that work. Patrick Pellicane and Miklós Ivanyi provided very helpful reviews of the content of this report.

Disclaimer

The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented. This document is disseminated under the sponsorship of the Department of Transportation Centers Program in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.

Abstract

Investigations into the effects of the addition of vertically-oriented shear spikes with fiberglass reinforced polymer rods have shown that the shear spikes increased the effective stiffness of the stringers of a full-scale timber bridge chord specimen. This was previously found to be true on dimension lumber and medium-sized timber. This report presents the results found from the flexural load testing of a full-scale timber bridge chord laboratory specimen. The bridge chord specimen was intentionally damaged to simulate degradation. Reinforcement was provided with 19 mm (3/4-inch) diameter fiberglass reinforced polymer shear spikes bonded to the wood by an epoxy resin. Shear spikes were installed in pairs vertically from the top of the member into pre drilled holes to provide horizontal shear resistance and to improve the flexural effective stiffness. Results from the testing showed that with the insertion of five sets of shear spikes an average effective stiffness of 91.6 percent was recovered in the four stringers of the chord.