Ten-Year Review of Monitoring System on I-35W Saint Anthony Falls Bridge


Lauren Linderman, Riley Brown, Rebekka McCoy, Carol Shield, Brock Hedegaard

June 2020

Report no. MnDOT 2020-19

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.

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