Structural Health Monitoring of the Indian River Inlet Bridge

Cardinal, Jack
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University of Delaware
The Indian River Inlet Bridge, located in Sussex County, Delaware, is a critical portion of the Route 1 Coastal Highway and allows many beach goers access to the Delaware shores. This concrete, cable stayed bridge was completed in early 2012 and just recently opened to full capacity. A Structural Health Monitoring (SHM) system was designed and installed into the bridge during the construction process and on April 30th the University of Delaware conducted a calibration load test. The data was then analyzed and evaluated to determine the nominal response of the bridge based upon the collected data. Using smoothing techniques, the immense amount of data was processed and different aspects of the bridge were investigated. This was then put into a load test report for the Delaware Department of Transportation (DelDOT). By primarily using strain data many areas were investigated. The fundamental period of the bridge was determined along with the maximum loading conditions that the bridge underwent. Distribution factors were calculated using a transverse flow of load analysis and many other responses that the bridge experienced during loading were delved into. These topics and more were all combined for a comprehensive overview of the bridge’s performance. A second load test on November 28, 2012 was conducted to induce different responses in the bridge with varying formations and to test the repeatability of the data recorded during the April test. The comparison between the tests was done by examining each test’s truck weights, peak responses, load distributions and time history responses. As a result of conducting this comparison the system’s overall accuracy was evaluated. Lastly, with this work there are many future applications that this system can be used for. Examples of such future uses would be the creation of standard testing procedure for the Indian River Inlet Bridge, extreme load monitoring, determining a loading threshold, as well as what ambient response data looks like on the bridge. As a result of examining permit loads a method was determined to predict vehicle weights on the bridge and an investigation into temperatures effects on strain gauges was completed. Overall, the Indian River Inlet Bridge’s integrated structural health monitoring system gives a high quality picture of the “health” of the bridge and has future applications in both monitoring and research.