Control Surveys for Major Bridges

Some old methods of surveying are combined with new ones to provide fast an very accurate survey control on major long-span bridges. The oldest type instrument, a mariner's navigation sextant, was used along with the more modern high accuracy devices. These instruments include optical theodolites, electronic distance measuring equipment, engineering lasers, computers, precise levels, depth recorders, two-way portable radios, and other related surveying equipment. The proper use of these instruments will provide the highest caliber survey control from initial planning to preliminary surveys, photogrammetric mapping, triangulation, hydrographic surveys, foundation explorations, property surveys, and primary survey control for construction. This paper covers the surveying procedures used for the planning and construction of the San Diego-Coronado Bay Bridge in California and the preliminary survey work being done for a proposed Southern Crossing of San Francisco Bay.