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Smart Rock Positioning for Scour Hazard Assessment of Bridges

Hydraulic effects are responsible for about 60 percent of the more than 1,500 U.S. bridge collapses. Traditionally, divers are sent underwater to inspect bridge foundations and document any riverbed erosion or scour holes that may compromise a foundation’s integrity.

This project aims to replace divers with smart rocks that automatically roll to the bottom of a scour hole under strong current to assess the scour-hole condition. A magnetometer installed on an unmanned aerial vehicle (UAV), remotely senses the depth of a scour hole by measuring magnetic fields surrounding the smart rocks.

The difference in two measurements over time reveals the movement of the smart rocks during that time period, with the vertical movement showing the development of scour hole depth. This critical data is then used by engineers to assess the stability of a foundation due to scour hazards.


The main focus of this project is to:

  1. Design, build and test a UAV with a ground-referenced global positioning system, a 3-axis magnetometer, a lightweight onboard computer, and one or two batteries for at least a 20-minute operation in field conditions.
  2. Investigate the effect of UAV operations on magnetic field measurements.
  3. Evaluate the localization accuracy of one, two, and three smart rocks.
  4. Demonstrate the field performance of smart rocks for scour monitoring at bridge sites.
Last updated: Thursday, March 29, 2018