Browsing by Subject "Recommendations"

Now showing 1 - 7 of 7
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    Debonded Strands in Prestressed Concrete Bridge Girders
    (Minnesota Department of Transportation., 2019-07) Osman, Mahad; French, Catherine
    There are three potential options to reduce end stresses in prestressed concrete bridge girders: drape strands, debond strands, or a combination of the two. In the draping option, a portion of the strands are raised from harp points within the girder to reduce the strand eccentricity at the girder ends. Large vertical reactions are required at the hold down points within the girder to resist the uplift of the draped strands. In addition, end cracking that follows the draped strand pattern is often observed, particularly in deeper sections. In the debonding option, a portion of the strands are debonded toward the girder ends to reduce the resultant prestress force. Concerns with debonding are its potential to reduce shear strength and to cause corrosion issues if moisture and deicing chemicals make their way into the girder ends along the debonded path. Due to potential corrosion concerns, MnDOT has prohibited strand debonding. However, as a means to eliminate some of the end cracking observed during fabrication with draped strands, this study was conducted to explore the use of debonded strands and to develop design recommendations. To this end, an extensive literature review was conducted regarding debonded strand research, and state Departments of Transportation with similar climates and fabricators were queried to learn from their experiences. Design recommendations and potential material specifications to protect debonded strands from corrosion are presented in this report.
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    Development of Best Practices for Inspection of PT Bridges in Minnesota
    (Minnesota Department of Transportation, 2012-04) Berg, Kyle Matthew; Schokker, Andrea J.
    This report focuses on post-tensioned bridges built in Minnesota prior to 2003. The scope is limited to providing a targeted check of bridges that are most likely to have grouting related corrosion problems based on a review of plans and inspection notes. The project consisted of three phases: 1) review of plans and inspection reports of 40 post-tensioned bridges constructed prior to 2003, 2) selection of 10 bridges for a limited onsite inspection of the exterior of the bridge, and 3) invasive inspection of three select bridges. The bridges were selected to represent different bridge construction types to provide a spot check of the post-tensioned bridge inventory in Minnesota. One of the three bridges has corrosion and voids due to poor grouting, one has major corrosion problem related to construction issues (but appears to have good grout), and one showed no tendon corrosion or grouting problems during the invasive spot checks. Recommendations are given at the end of the report specific to the bridges that were investigated as well as for a general inspection plan for post-tensioned bridges in Minnesota. A concise guide for bridge inspection staff is provided that is specific to post-tensioned bridges.
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    Disc shaped compact tension (DCT) specifications development for asphalt pavement
    (Minnesota Department of Transportation., 2019-06) Dave, Eshan V; Oshone, Mirkat; Schokker, Andrea; Bennett, Chelsea E
    The disc-shaped compact tension (DCT) fracture energy test has been shown to discriminate between asphalt mixtures with respect to their thermal cracking potential. This research refines the DCT fracture energy testing procedure, identifies needed adjustments in asphalt mixture to increase fracture energy, determines the suitability of DCT-test-based parameters as indicators of reflective cracking, and proposes threshold values to lower the potential for premature reflective cracking in asphalt overlays. A number of recommendations have been developed to implement outcomes of this research as well as to fill knowledge gaps identified through this study.
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    HPV Vaccine Recommendations for Women over 26 years old
    (2012-07-26) Durakovic, Selma
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    Scenarios and Justification for Automated Vehicle Demonstration in Rural Minnesota
    (Center for Transportation Studies, University of Minnesota, 2019-06) Douma, Frank; Petersen, Erin
    Automated vehicles (AVs) have the potential to disrupt the current transportation system and culture. While experts debate the exact timeline, the question is likely a matter of when, not if. Therefore, communities of all kinds need to prepare for this future. Small urban and rural communities, in particular, could benefit from the development of the technology, as many of their residents are unable to drive due to age and/or disability. Automated technology could provide a cost-effective and efficient solution for these communities, but so far, most of the AV testing has been conducted in densely populated urban areas. This project provides justification for why rural and small urban communities should host AV demonstrations and how these communities can create a plan to do so. We accomplish this task by providing information about rural and small urban communities and by reviewing the current state of AV technology, the legal environment for AVs, and best practices from past and current AV demonstrations. We also engage with two small urban communities in Minnesota to gather information about real community needs, desires, and limitations.
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    Towards location-aware news feed and recommendations
    (2014-06) Bao, Jie
    With the advances in positioning techniques, such as GPS, cell-towers and WiFi, users can enjoy location-based services more easily than ever before, e.g., on their smart phones and GPS devices. However, with the popularity of recommendation (e.g., Amazon \& Netflix) and socialization (like Facebook and Twitter) functionalities in the web services, users of location-based services are no longer satisfied with the static results returned from a spatial database. At the same time, more and more spatial information, such as geo-tagged photos and check-ins are generated in the traditional social networking services. As a result, users are calling for the next generation of location-based service, i.e., location aware news feed and recommendations, which can provide the user with the more personalized and socialized services.In this thesis, I present my vision of the next generation of location-aware service, which enables the social networking services with location awareness. First of all, in this thesis, I present the unique properties that location information brings to the traditional social networking and recommendation services. After that, I summarize the potential challenges in building efficient and effective location-aware news feed and recommendation services from both the system and user's perspectives. Then, I present a prototype system, (i.e., Sindbad, a location-aware social networking system), to demonstrate three main services provided in the system, as: 1) location-aware news feed service, which efficiently returns the user with spatial-aware messages from her subscribed friends. 2)~location-aware news ranking services, which provide a set of efficient news ranking and message updating algorithms for the user to get more relevant news, based on her social-spatial preferences. And 3)~location-aware recommendations, which provides suggestions based on the social knowledge from the local experts and the preferences mined from a user's location history. Finally, the thesis is concluded with the overall contributions and some potential further research directions.
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    Transforming the University: creating a new design college
    (University of Minnesota, 2005-12-12) Solomonson, Katherine; Yust, Becky
    To create a plan for a new, nationally distinctive, multidisciplinary college of design incorporating the Departments of Architecture, Landscape Architecture, and Design, Housing, and Apparel, and associated centers. The new college would aspire to be an international and national leader in multidisciplinary research, creative production, teaching, and public engagement in a wide variety of design-related fields.