Browsing by Author "McCoy, Rebekka"

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    Insights Gained from I-35W Saint Anthony Falls Bridge Long-Term Monitoring System
    (2021-05) McCoy, Rebekka
    The new I-35W Saint Anthony Falls Bridge in Minneapolis, MN was fit with a system over 500 sensors to investigate structural behavior, which has been collecting data since the bridge opening to traffic in 2008. This large dataset presents a unique opportunity to investigate the I-35W Bridge’s behavior over years, seasons, and conditions, with the underlying objective to develop structural health monitoring protocols with long-term data. Long-term structural health monitoring is one approach to assist in the maintenance and management of structural systems. The long-term monitoring strategy presented updates the previous monitoring framework in Hedegaard et al. 2017 to account for uncertainty in the time-dependent deflections when establishing the bounds on the predicted behavior of the bridge. Additionally, the long-term data set is leveraged to compare the behavior of the bridge under environmental loading to design assumptions allowing for evaluation of serviceability stresses due to maximum temperature gradients at the midspan of the bridge.
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    Ten-Year Review of Monitoring System on I-35W Saint Anthony Falls Bridge
    (Minnesota Department of Transportation, 2020-06) Brown, Riley J.; McCoy, Rebekka; Shield, Carol K.; Linderman, Lauren E.; Hedegaard, Brock D.
    The I-35W St. Anthony Falls bridge was highly instrumented with over 500 sensors to verify design assumptions, serve as a testbed to examine bridge sensing techniques, and evaluate the effectiveness of different bridge monitoring strategies. The instrumentation deployed on the bridge to investigate the structural behavior included vibrating wire strain gages (VWSGs), thermistors, fiber optic sensors (SOFO), resistance strain gages, linear potentiometers, accelerometers, and corrosion monitoring sensors. This report documented the successes and challenges of the monitoring program over the first ten years of the bridge’s life. In particular, the effectiveness of different strain measurement techniques and sensor distributions were addressed. Previous investigations of temperature-dependent and time-dependent behavior were also expanded with the larger data set to better understand the behavior of post-tensioned concrete box girder structures with the potential to impact future designs.