| Co-Investigator(Kenkyū-buntansha) |
前田 強 兵庫県土木部道路建設課, 主査
梶谷 義昭 兵庫県吉川町役場, 技監
MIYAGAWA Toyoaki Kyoto University, Faculty of Engineering, Research Associate, 工学部, 助手 (80093318)
FUJII Manabu Kyoto University, Faculty of Engineering, Professor, 工学部, 教授 (30031074)
NISHIMURA Akira Kobe University, Faculty of Engineering, Professor, 工学部, 教授 (00031039)
MAEDA Tuyoshi Hyogo Prefectural Government, Chief Engineer
KAJITANI Yoshiaki Yokawa-cho Town office in Hyogo Pref., Head Engineer
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| Research Abstract |
The necessity of developing a computer-aided bridge rating system gas been pointed out for maintenance, diagnosis, repair and rehabilitation of existing bridges. There are multiple processes of damage with a number of damage factors in existing bridges in service. The major part of bridge rating which is the kernal of bridge maintenance system has been constructed based on the subjective judgment of experts in the related fields. By considering that there is a lack of experts in the increasing filed of bridge maintenance and for the exact diagnosis of bridge conditions, the systematization of bridge rating including the subjective information of bridge engineers such as professional experience, knowledge on bridge rating, etc. has become an important problem.
In this paper, an expert system for serviceability rating of concrete bridges (Bridge Rating Expert System) is developed based on a combination of several components which are the knowledge base including the subjective information
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related to the rating, the inference engint, the data reference module, the calculation module, the explanation module, the knowledge acquisition module and the I/O module. The computer system and main language which is used in the expert system are the PC-9801VX41 personal computer made by NEC corporation, Japan and PROLOG and C languages, respectively.
For the construction of the knowledge base including the subjective information related to the rating, it is an unavoidable problem in dealing with subjective informations which cannot be allotted binary codes such as true or false. As a remedy to this problem, a concept of the basic probability according to the Dempster ＆ Shafer s theory is introduced in the present system. The upper probabilities in the Dempster ＆ Shafer's theory to introduce experiences and knowledge accumulated into the knowledge base are obtained through questionnaires sent out to bridge experts.
The results of the rating at the final stage produced by this system are considered to be represented by five elements expressed by the linguistic expressions "safe" "slightly safe" "moderate" "slightly danger" "danger" with the fuzziness value which is the degree of subjective uncertainty.
A few concrete bridges on which field data have been collected are analyzed to demonstrate the applicability of this expert system. Through the application to the deteriorated reiforced concrete bridge girders and slabs, reasonable results are obtained by inference with the expert system. Less
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