Marine construction, inspection, and maintenance involves the building, upkeep, and potentially the removal of structures that are constantly or regularly under water; some would also include the maintenance of harbors and waterways through dredging operations. Examples of projects include bridge piling/foundation laying and monitoring, pipeline and oil field layout construction and inspection, rig positioning and monitoring, and pier and quay wall construction. Prior to construction, a seabed survey may be done using single beam or multibeam sonar; sometimes multiple surveys will be done and compared to monitor sediment migration. During construction, AUVs and ROVs with video streams might be deployed to act as “eyes” on the scene, or in some cases to assist in the building or excavation. Post-construction surveys and regular inspection surveys are done to look for issues such as excessive scouring or structural problems. Often, inspection of structures in shallow water is done by divers using slow hand inspection in dark, turbid conditions. In deep water, ROV or AUV-mounted multibeam sonars and sidescan sonars are used to create a picture of the underwater environment. This option has recently been employed in shallow water surveys, in conjunction with or as an alternative to
diver inspection; multibeam sonars are “tilted” to image walls and vertical structures, and multibeam water column data is used to image structures well off of the seafloor. When combined with simultaneous laser scanning above the water, a seamless picture is created.
Fledermaus is the ideal tool for marine construction visualization. Integration of all available data types, including bathymetry, sidescan, seismic profiles, water column data, and layout drawings is quick and intuitive, providing users with an interactive 4D scene for planning, analysis, and presentation. Scenes can be shared with colleagues and clients using iView4D, the free downloadable viewer, or alternatively you can create fly-through movies in WMV or MPEG format for distribution. If data processing is required, Fledermaus providesCUBEThe CUBE algorithm was developed by Dr. Brian Calder at the Center for Coastal and Ocean Mapping/Joint Hydrographic Center at the University of New Hampshireand Area-Based processing for multibeam bathymetry, mulitbeam water column processing, and multibeam backscatter processing. If AUVs or ROVs are part of your effort, you can stream the real-time position for up to 10 vessels in your 4D scene so that all parties can keep an eye on operations; this functionality can also be used for pre-operation planning and post-operation presentation.
For examples of Fledermaus being used for marine construction, inspection, and maintenance, please see the Substructure website.
Data courtesy of MA-DOT and Substructure