Smart Rock Technology for Local Scour Monitoring of Bridge Structures

This study gives a comprehensive review on the smart rock technology to monitor local scour depth of bridge piers or abutments, which was originally proposed by our group in 2015. The smart rock is one or more stacked magnets encased in a concrete ball that can automatically roll to the deepest point of a scour hole around a bridge pier and provide its location through remote measurement over time. As of today, three types of spherical smart rocks designated as arbitrarily oriented system (AOS), automatically pointing south system (APSS), and automatically pointing upward system (APUS) have been developed. This study gives a comprehensive review on the smart rock technology for local scour monitoring of bridge piers, in terms of sensing principle, advantages and disadvantages, localization algorithm, effective monitoring range, as well as field test. The smart rock technology was also compared with other technology to monitor bridge scour such as optical fiber sensor, ground penetration radar, sonar, magnetic sliding collar, and so on.