Field Application of Magnet-Based Smart Rock for Bridge Scour Monitoring

Fujian Tang, Yizheng Chen, Chuanrui Guo, Liang Fan, Genda Chen, Yan Tang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

16 Citations (Scopus)


In this study, a smart rock, which is a magnet embedded in a concrete ball and whose direction is always pointing downwards, is proposed to monitor bridge scour depth. Based on the theory of magnetic field, the distribution of the magnet-induced magnetic field (MMF) induced by the smart rock was derived. An algorithm was developed to localize the position of the smart rock. Field tests were conducted at a bridge pier at three different times. Both the intensities of the ambient magnetic field (AMF) and the total magnetic field (TMF) were measured with a magnetometer. Results showed that the presence of steel reinforcement or steel girders in the bridge changed the distribution of the geomagnetic field. The algorithm successfully localized the position of the smart rock with an error ranging from 0.26 to 0.33 m, which satisfied the requirement for engineering applications. The effective monitoring range depends on the variation of the AMF, and the maximum monitoring depth ranged from 11.5 to 8.5 m as the standard deviation of the AMF increased from 32.3 to 80.75 nT.

Original languageEnglish
Article number04019015
JournalJournal of Bridge Engineering
Issue number4
Publication statusPublished - 1 Apr 2019
Externally publishedYes


  • Bridge scour
  • Localization algorithm
  • Magnetic field
  • Non-contact measurement
  • Smart rock
  • Structural health monitoring

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction


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