Browsing by Subject "Bridge management systems"

Now showing 1 - 5 of 5
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    Bridge Health Monitoring and Inspections – A Survey of Methods
    (Minnesota Department of Transportation, 2009-09) Gastineau, Andrew; Johnson, Tyler; Schultz, Arturo
    Since the collapse of the I-35W bridge in August 2007, bridge health monitoring has become an area of intense interest. This report defines terminology related to bridge health monitoring and provides a general glossary of available monitoring systems. The glossary is meant to help readers make an informed decision by understanding how different systems function and their strengths and weakness. The authors developed a questionnaire to send to commercial companies offering monitoring systems. Of the 72 questionnaires that were sent to commercial companies, 38 companies responded and are included in this report. From information provided with these questionnaires, available commercial systems are briefly summarized. Criteria for system evaluation were developed to help the bridge owner narrow down company choices for bridge application. After the owner answers a set of questions pertaining to a particular bridge, a program developed in Microsoft EXCEL helps the bridge owner decide the best system for a particular situation. An example is provided for program clarity. Once company choice is narrowed down, additional criteria were developed to aid in final product choice.
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    Enriched Sensor Data for Enhanced Bridge Weigh-in-Motion (eBWIM) Applications
    (Center for Transportation Studies, 2018-11) Kumar, Ravi; Schultz, Arturo; Hourdos, John
    Bridge weigh-in-motion (BWIM) systems, which measure bridge deformation under live loading to estimate weights of passing vehicles, have been in development since Moses first introduced the concept in 1979. Despite advances made since its introduction, important limitations for BWIM systems still exist. A feasibility study was performed to determine if some of the limitations—including poor accuracy with multiple vehicle passage, either in tandem or side-by-side; and inability to accurately capture the passage of a vehicle moving at variable speeds—could be overcome by enriching the dataset available to the BWIM system. Non-contact measurements collected in real time on the topside of the bridge can enrich the dataset, and by taking advantage of these measurements a more accurate and effective enriched bridge weigh-in-motion (eBWIM) system can be developed. Several sensing technologies were reviewed including fiber Bragg gratings, MEMS accelerometers, microwave radar sensors, magnetic sensors, active infrared detectors, and video image vehicle detection systems. Preliminary results indicated that there was no clear candidate for a fully mature sensing system that would satisfy all the criteria in this study. However, microwave radar sensors have a reasonably low cost, are the least intrusive, and perform better in all weather conditions compared to the other sensors. A testbed using radar sensors is proposed to investigate the accuracy of the eBWIM system. If the desired accuracy of the eBWIM system can be achieved, its implementations should prove to be invaluable for enforcing bridge weight limits, studying truck traffic patterns, and managing bridge inventories.
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    Feasibility of Vibration-Based Long-Term Bridge Monitoring Using the I-35W St. Anthony Falls Bridge
    (Minnesota Department of Transportation, 2017-01) Gaebler, Karl O.; Shield, Carol K.; Linderman, Lauren E.
    Vibration based structural health monitoring has become more common in recent years as the required data acquisition and analysis systems become more affordable to deploy. It has been proposed that by monitoring changes in the dynamic signature of a structure, primarily the natural frequency, one can detect damage. This approach to damage detection is made difficult by the fact that environmental factors, such as temperature, have been shown to cause variation in the dynamic signature in a structure, effectively masking those changes due to damage. For future vibration based structural health monitoring systems to be effective, the relationship between environmental factors and natural frequency must be understood such that variation in the dynamic signature due to environmental noise can be removed. A monitoring system on the I-35W St. Anthony Falls Bridge, which crosses the Mississippi River in Minneapolis, MN, has been collecting vibration and temperature data since the structures opening in 2008. This provides a uniquely large data set, in a climate that sees extreme variation in temperature, to test the relationship between the dynamic signature of a concrete structure and temperature. A system identification routine utilizing NExT-ERA/DC is proposed to effectively analyze this large data set, and the relationship between structural temperature and natural frequency is investigated.
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    Innovative Technologies for Lifetime Extension of an Aging Inventory of Vulnerable Bridges
    (Center for Transportation Studies, University of Minnesota, 2011-12) Gastineau, Andrew; Wojtkiewicz, Steven; Schultz, Arturo
    This report refines a response modification framework, previously developed by the authors, which combines technological developments in the fields of control systems, health monitoring, and bridge engineering to increase bridge safety. To enhance the modification framework, the numerical bridge model is refined and additional modification apparatuses are added to the numerical model to further develop and confirm the advantages of the response modification approach. A parameter study of the modification apparatus characteristics is carried out to optimize member sizes and modification device characteristics. Finally, a frequency response analysis is carried out to investigate the use of a semi-active system within the scope of the response modification framework.
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    Remaining Service Life Asset Measure, Phase 1
    (Minnesota Department of Transportation, 2018-07) Kumar, Ravi; Matias de Oliveira, Jhenyffer; Schultz, Arturo; Marasteanu, Mihai
    There is a critical need to use a common metric, such as a service life parameter, across many different types of infrastructure assets. MnDOT has used the remaining service life (RSL) measure for pavement condition for several years and is starting to use it for bridge condition. In this study, researchers examined what has been done to date and what tools and methodologies are available nationally and internationally, and made recommendations on a future measure that can be used to show the "true" condition of the system. First, a literature review was performed to summarize current methods used in asset management and life-cycle cost analyses. A survey was also performed to collect information from agencies around the country. An assessment of current practice used by MnDOT Bridge Office and Materials and Road Research Office was performed next to identify similarities and differences between the two approaches. Based on the information collected, suggestions for a common method were presented and guidelines for a work plan for a follow-up phase 2 were developed.