High-Resolution Acoustic Multibeam Surveys for Bridge Assessment

Data Type &Technique Coverage Resolution Primary Data Products / Relevant Info Sample Data ProductsBathymetry Vert ‐ cm Sparse, low‐resolution bathymetrySingle‐Beam Horiz: cm ‐ m Relatively low cost and complexityEchosounder Along‐track "Fathometric surveys" in bridge applicationspoint dataCommon Frequencies: 20 ‐ 400kHzBathymetryHigh‐resolution bathymetry and backscatter imageryImagery Vert ‐ cm High cost and complexityMultibeam Horiz: cm ‐ m Effective at mapping vertical structuresEchosounder Wide Swath Proper installation and integration are criticalPoint DataCommon Frequencies: 200 ‐ 450kHzGeo‐referenced 2D plan‐view mosaicImageryModerate cost and complexitySide‐Scan Vert ‐ N/A Towfish positioning drives horizontal resolutionSonar Wide Swath Horiz: m Characterize sediments / identify objectsPoint DataCommon Frequencies: 100 ‐ 1200kHz(a)Non‐georeferenced 2D image of structural faceImageryModerate cost and complexitySector‐Scanning Vert ‐ N/A Geo‐referencing and point cloud creation is complexSonar Image From Horiz: cm ‐ m Quanatitative bathymetry data is limitedOccupied PointCommon Frequencies: 300 ‐ 1200kHz(a) Image courtesy of Edgetech (www.edgetech.com/edgetech)Table 1. Overview of acoustic survey techniques that are used to support bridge‐related survey activities.9