Browsing by Author "Wacker, James"
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Item Development and Integration of Advanced Timber Bridge Inspection Techniques for NBIS(Center for Transportation Studies, University of Minnesota, 2015-01) Brashaw, Brian; Dahlberg, Justin; Hosteng, Travis; Wacker, JamesMinnesota has over 2,000 bridges that contain structural timber in the superstructure or the substructure. Historically, inspections for timber bridges have been mostly limited to visual inspection, hammer sounding and probing. These techniques have proven appropriate for advanced decay detection, but are inadequate for early stage or internal deterioration. During this project, new advanced inspection techniques and equipment were identified that were capable of improving the quality of timber bridge inspection. This equipment and technologies were introduced into routine bridge inspections through the development of standard inspection protocols, integration of the results into bridge data management software, development of a customized inspection manual, outreach training for MnDOT districts and state counties, recommendation of equipment purchases, and completion of an economic assessment on the use of advanced inspection techniques. Implementation of these inspection techniques will support the long-term service life of Minnesota’s timber bridges and will improve the safety and reliability of Minnesota’s bridges.Item 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, RobertModern 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.