Investigation of the Relative Safety of Alternative Navigational System Designs for the New Sunshine Skyway Bridge: A CAORF (Computer Aided Operations Research Facility) Simulation

摘要

The relative safety afforded the new Sunshine Skyway Bridge by three alternative navigational system designs was studied. A 'navigational system design' was a specific configuration of channels, aids to navigation, and shipboard navigation aids in the vicinity of the bridge. The first design included a relocation and redesign of the new bridge when compared with the existing bridge. The second design included the availability of a precision electronic aid to aid pilots in determining their position. The third design included a redesign of the channel approach to the bridge which displaced a course change that was less than one nautical mile to almost three nautical miles from the bridge. A fourth design was also included in the study to serve as a baseline condition against which to compare the three alternatives. This design was modelled to include the existing Sunshine Skyway Bridge and the channel and aids to navigation configuration that existed in May 1980 when the SUMMIT VENTURE struck the bridge causing extensive damage to the bridge and the loss of 35 lives. Nine scenarios were developed to compare bridge safety of the four designs during the transit of a 160,000 DWT tanker. Safety was principally defined in terms of measures of vessels proximity to bridge structures. The transits were generally made during adverse conditions consisting of heavy fog or thunderstorms. A limited number of transits were made under favorable environmental conditions to aid in the establishment of baseline levels of performance. The transits were made by seven Tampa Bay pilots. The results indicated that vessel transit under thunderstorm conditions were less safe than transits under fog conditions.