Preliminary Navigation Safety Evaluation On Bridge Waterway Based On Unascertained Measure

With the rapid development of the economy in China, the construction of transportation and communication has also made great progress, and the number of bridges striding over rivers and seas has increased quickly. Those bridges have made great contribution to the economic development of longshore areas, but on the other hand, they have inevitably caused bad effects on the vessels' navigation in bridge waterway area. In order to analyze and study the probable effects that the bridges may have upon the navigation environment of bridge waterways to insure the safety of the bridges and vessels, it is greatly significant and necessary to carry out preliminary evaluation on the impact of the bridges before construction.The present paper first introduces the knowledge on unascertained information and unascertained mathematics, then analyzes the factors affecting navigation safety in bridge waterway, and sets up the multi-level index system of bridge waterway safety evaluation. Subsequently, the paper utilizes improved AHP to determine the weight of evaluation indexes and establishes the unascertained measure model of preliminary navigation safety evaluation in bridge waterway. As to the uncertainty of experts' marking in the assessment, the paper introduces the concept of expert credibility, then on this basis, explores the method of unascertained conclusion synthesization, and quantifies experts'uncertainty. Finally, the paper applies the evaluating method of unascertained measure to the birdge waterway of proposed Hutong Railway Cross-River Channel and concludes its safety grade. Then the paper verifies the assessment's correctness by comparing its result with the result of shiphandling simulator experiments. This example proves that the evaluating method of unascertained measure has high maneuverability and accuracy, and it can be applied in general safety assessments.