| Abstract: | Bridge Rail EXpert System (BREXS) is a rule-based expert system developed to aid novice engineers in coping with bridge rail design and retrofit problems. Development goals for this system are to incorporate bridge rail knowledge bases, bridge rail databases, analytical computer codes, and fuzzy logic decision-making capabilities into a comprehensive decision support system. The resulting system is intended to assist less experienced bridge engineers in choosing an optimum rail that conforms to standard specifications and satisfies service requirements. BREXS is customized to meet standard requirements of bridge railing practice in Texas. Knowledge from state level officials and several experienced district engineers were elicited and represented in the form of rules and databases. Knowledge bases and supporting analysis programs are integrated under a graphical user interface. Integration is transparent to the user, thus ensuring ease of use. BREXS consists of two subsystems that deal with new construction and retrofit problems. BREXS is a relatively small expert system which contains a total of approximately 400 rules in its knowledge bases. Problem-solving strategy is based on the derivation approach. BREXS infers functional requirements from the characteristics of a given bridge site. Each standard Texas rail is then evaluated for its merits and drawbacks for installation based on a set of criteria. The MYCIN method for uncertainty treatment is employed to accommodate determination of the most appropriate rail. The optimal position for installation on an existing bridge and type of anchorage are also determined for retrofit problems. Special attention is placed on design of the user interface to ensure ease of use. Interactive windows and pull-down menus facilitate input of data and execution of the system. From the interface, users can also access the bridge rail database and update the records. On-line help on system usage is available. A scale drawing of the recommended rails and existing bridge can be displayed and printed to accommodate preparation of construction drawings... |
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