Implementation of structural monitoring to assess the performance and serviceability of concrete and steel girder bridges
Abstract
This research focuses on bridges and the development of structural monitoring systems used for both concrete and steel bridges. Parts of two bridges were built with a combination of sensors attached to a data acquisition system powered by a solar panel and battery, where data is transmitted wirelessly through cell phone technology. The research represents the first efforts to develop remote structural monitoring that is robust and reliable to survive through the construction of both concrete and steel bridges and continue to function from the beam fabrication through bridge construction and even now as the bridges have been in service for more than two years. Prestressed Concrete Bridge Beams were instrumented during beam fabrication. Concrete strains, concrete temperatures, and ambient temperatures are measured continuously from the time immediately before the casting of the beams, through fabrication, including detensioning of prestressing strands, through handling and storage, transportation, and erection, through bridge construction, and now during life-in-service. Sensors capture concrete strains and temperatures from early ages. These data are useful to assess important variables regarding the design and construction of prestressed concrete bridge beams and the bridges made with those beams. Specifically, prestress losses were assessed, and beam cambers were measured. Designs were varied to investigate different design choices to control and limit both prestress losses and cambers. In-situ load testing was performed on the completed concrete bridge structure. These data are used to investigate design parameters, specifically distribution factors for bridges' design and load rating and the dynamic amplification factor for bridges. Recommendations are made from the research. Findings from the research demonstrate the effectiveness of including fully tensioned top strands in prestressing strand patterns and mild horizontal steel as part of the primary reinforcement at midspans of bridge beams. The research shows that both of these design choices are effective in limiting prestress losses and beam cambers. These techniques can be employed nationwide and worldwide where precast, prestressed concrete bridge beams are used.
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- OSU Dissertations [11222]