CAESAR: AN EXPERT SYSTEM FOR EVALUATION OF SCOUR AND STREAM STABILITY

This report documents the development and testing of a field-deployable, knowledge-based decision support system that assists bridge inspectors by acquiring, cataloging, storing, and retrieving information necessary for the evaluation of a bridge for the presence of scour. More importantly, the expert system provides an independent scour risk evaluation of the site conditions, evaluates the bridge and substructure elements for failure risk, and provides both explanations of the scour risks and suggestions for scour mitigation. The contents of this report are, therefore, of immediate interest to both highway and rail transit professionals responsible for operating, inspecting, maintaining, and upgrading scour susceptible structures. The report is also of interest to those charged with overall system safety and budgets as well as to policy makers. CAESAR (Catalog And Expert evaluation of Scour risk And River stability) offers an organized inspection routine based on entering the answers to specific questions into a laptop computer, ensuring nothing is overlooked. The inspector is aided by extensive help screens amply illustrated with photographs to ensure consistency among inspection personnel. The entered information is combined with static bridge information, such as as-built plan information previously entered in the office, and any previous bridge inspection data before being evaluated using built-in risk evaluation expertise provided by several nationally recognized scour specialists. CAESAR combines these various sources of information and provides specific conclusions concerning the scour risk at piers and abutments. In addition, CAESAR provides general site conclusions for lateral stream stability, vertical stream stability, and contraction scour risk.