Development of an Expert System for Servicesbility Rating of Concrete Bridges

指出了为既有桥梁的维护、诊断、维修和改造而开发计算机辅助桥梁评级系统的必要性。在役桥梁的损伤过程是多过程的，损伤因素也是多方面的。桥梁等级评定是桥梁养护体系的核心，其主要部分是建立在相关领域专家的主观判断基础上的。随着桥梁维修领域的日益扩大，以及对桥梁状况的准确诊断，桥梁评估的系统化已成为一个重要的问题，其中包括桥梁工程师的专业经验、桥梁评估知识等主观信息。以混凝土桥梁的主观信息为知识库，建立了混凝土桥梁正常使用等级评定专家系统 ...更多信息 涉及评分、推理机、数据参考模块、计算模块、解释模块、知识获取模块和I/O模块。该专家系统采用日本NEC公司的PC-9801 VX 41个人计算机，主要语言分别为PROLOG和C语言。在建立包含评分主观信息的知识库时，对真假等不能用二进制编码的主观信息的处理是一个不可避免的问题。为了解决这一问题，本文根据Dempster & Shafer的理论，引入了基本概率的概念。通过对桥梁专家的问卷调查，获得Dempster & Shafer理论中将积累的经验和知识引入知识库的上概率，并将该系统最终产生的评级结果用语言表达“安全”、“稍安全”、“中等”、“稍危险”、“危险”的5个元素表示通过对几座混凝土桥梁的实测数据分析，验证了该专家系统的实用性。通过对钢筋混凝土桥梁梁板劣化问题的应用，通过专家系统的推理，得到了合理的结果。少

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 … More 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