Browsing by Subject "Timber"

Now showing 1 - 5 of 5
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    Cold Temperature Effects on Stress Laminated Bridge Decks
    (Minnesota Department of Transportation, 1997-11) Seavey, Robert T.; Erickson, Robert W.
    This study evaluated the thermodynamics of stress-laminated bridges under laboratory conditions. After assembling three timber laminated bridge deck panels of 120" x 43" x 12", high tension rods were used to form "stress-laminated" panels. Researchers placed the panels in a laboratory freezer, with cold temperature settings of 10*, 0*, -10*, -20°, and -300 Fahrenheit and repeated the process three times, each with the wood at a different moisture content--a "green" moisture content greater than 30 percent, a 17 percent moisture content, and a 7 percent moisture content (mc). The results showed that the bar force reduction in the green moisture content sample was significantly greater than in either the 17 percent or 7 percent me tests. The study concluded that the moisture content levels and temperature fluctuations cause variations in rod stressing levels; that the tensioning losses occur within a few hours of the temperature drop; that the green moisture content levels have a severe adverse effect on the stressing levels; and that tensioning levels somewhat stabilize with moisture contents below 17 percent. Based on this study, it would appear that any existing stressed bridge decks should be closely monitored until the moisture content of the members is less than 19 percent. Further study may be needed to determine the behavior of bridge decks with a moisture content above 17 percent and below the fiber saturation point.
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    Development of Cost-Competitive Timber Bridge Designs for Long-Term Performance
    (Minnesota Department of Transportation, 2020-06) Brashaw, Brian; Wacker, James; Fosnacht, Don; Aro, Matt; Young, Matthew; Vatalaro, Robert
    Modern timber bridges have shown that timber is a durable option for primary structural members in highway bridges and can perform satisfactorily for 50 years or longer when properly designed, fabricated and maintained. However, various cost assumptions have indicated that timber bridges are more expensive than concrete bridges. This project was undertaken to better understand the benefits and costs of using timber bridges as a viable substitute for other bridge construction materials and designs. Two demonstration construction projects were completed to develop comparative information. A steel girder with a transverse glulam deck bridge with a curbless, crash-tested railing system was built, and a spike-laminated longitudinal deck bridge was constructed. Both projects were completed and allowed for a good comparison to be developed both in terms of project-specific cost and the time required for bridge construction completion. These projects showed that the main advantage of a timber bridge is the speed of superstructure construction with the other costs similar to that of other materials. It is clear from previous case studies, interviews with engineers, contractors, and suppliers, and the projects that timber superstructures can be installed within days to weeks, compared to months for other materials.
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    Northeast Minnesota Industry Cluster Study
    (2001) Munnich, Lee W; Chatfield, Nathan; Schrock, Greg; Lichty, Richard W; McIntosh, Chris; Wittrock, Tiana
    This major study explored factors contributing to the economic competitiveness of northeastern Minnesota communities and counties. It has a strong focus on economic and industrial development. The study focuses on four “clusters”: forest products, tourism, health services and information technology. The first two clusters are assumed to require an adequate supply of water, and are assumed to greatly influence the quality and quantity of water available for multiple uses. Summary: "This regional study sought to understand the issues shaping the competitiveness of Northeast Minnesota’s industry clusters. The study follows the Michael Porter 'industry cluster' approach to understanding competitiveness. The project identified four clusters for the region: 1) forest products, 2) tourism, 3) health services, and 4) information technology. Focus groups and individual interviews with local business leaders and economic development professionals offered insight into the industries. The study region encompassed a twelve-county area of northeastern Minnesota that centered on the city of Duluth (St. Louis County). Also included are Aitkin, Carlton, Chisago, Cook, Isanti, Itasca, Kanabec, Koochiching, Lake, Mille Lacs, and Pine Counties.”
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    Sampling and measuring timber in the private woodland
    (University of Minnesota. Department of Forest Resources. Minnesota Extension Service, 1986) Blinn, Charles R; Burk, Thomas E
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    Value Chain Analysis in Lampung Province, Indonesia
    (2019-09) Masterpole, Zoe C; Teleposky, Emily R; Thompson, Josh A; Zaghloul, Sara E