Underwater inspection of bridges using divers is easier than it was a few years ago. It requires many dives of short duration at many locations. Scuba diving can be used in many cases. The equipment is lightweight and cost effective. The Federal Highway Administration special projects office is developing an inspection program which will be presented to the states in seminars and will cover special inspection methods, how to inspect fracture-critical members of structures, and underwater instruction, including a field demonstration of diving techniques and diving inspection. The U.S. Navy has three levels of underwater inspection. Level one is the swim by. In level two, 10% of the structure is cleaned for a more detailed inspection. Level-three inspections involve making detailed measurements of about 5% of the structure. Underwater documentation is completed with a camera, which is both easy and inexpensive. In dirty water a plexiglass clear water box helps to get decent pictures. Underwater videos are useful in some situations. On new bridges, good design and construction can greatly reduce the chances of corrosion problems. Dense concrete, good cover, epoxy-coated rebar, good drainage, and alternative deicers help keep a new bridge in shape. Cathodic protection costs have dropped. Missouri is the main user of cathodic protection on bridges. Contractors should prove it's working and it should be monitored. Painting is a tried and true method of controlling bridge corrosion, and new materials make it more effective than ever. However, the problem of containment is difficult. Capturing old paint and rust as well as containing new paint is increasingly being required by environmental agencies and new legislation.

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Filing Info

  • Accession Number: 00485311
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 31 1989 12:00AM