Underwater vision

This article examines the use of sonar imaging as an aid in inspecting underwater parts of bridge piers. Traditional inspection techniques employing commercial divers can be hazardous and potentially inconsistent. Some improved techniques involve the use of echo sounders or towed side-scan sonar: these provide good visualisation but are affected by currents and the manoeuvrability of the survey vessel. Mechanically-scanned sonar systems use a stepper motor to change the imaging angle. A dual transducer arrangement allows the user to compute detailed profiling and imaging visualisation surveys. Very narrow beam patterns and high resolution scanners are used for bridge applications. The sonar head can be mounted on a weighted tripod, and moved around the structure to produce a composite image. Use of a mechanically-scanned sonar makes it possible to establish baseline surveys for new and old bridges and improves safety in diver inspections. Substructure inspection is seen as best carried out by a combination of technologies and disciplines.


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Filing Info

  • Accession Number: 01051127
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Jun 11 2007 1:28PM