The Research On Bridge Life Cycle Design Scheme Based On The Multiple Attribute Decision Making Theory

Bridge life cycle design(short for BLCD), in which the bridge is considered as a special commodity, develops the design concept of sustainable development throughout the whole life, with the pursuit of beauty, low-cost, better-performance, environmental protection and so on. Thus the BLCD decision-making belongs to the multi-attribute decision-making issue. Recently, the bridge engineering accidents happened a lot, causing the immeasurable economic loss and social effects. So how to establish a reasonable risk-assessment model with the application of the thought of Bridge Life Cycle Design, is the key to eliminate the hidden accident in the bud stage. And to achieve the each goal of whole-life-design in the process of decision-making is based on the establishment of a scientific and effective model for multi-objective decision.This paper studied and summarized the domestic and foreign research progress of multi-attribute decision and problems, and put forward a multi-attribute decision-making model suitable for the whole life design in bridge engineering. In the model, the comprehensive weights of attributes can be calculated by the Game combination weighting method, based on the fuzzy number and entropy weight. The project's feasibility was carried out based on membership functions, while the optimization decision was done based on fuzzy numbers geometric sorting method.At various stages of bridge whole life cycle, the risk evaluation system and a BLCD risk assessment model were established after the risk's identification and analysis from four aspects like the natural risk, artificial risk, technical factor and degradation factor. The risk attributes' weights and priority can be gained with the combination the triangular fuzzy AHP with entropy weight by the Game Theory, with both experts' judgment and engineering objective information considered, which helps to improve risk disaster warning mechanism, effectively reduce or avoid bridge accidents, and provides guidance for the enterprise to manage the risk as well. Based on the membership function and maximum membership degree principle, the feasibility of engineering project can be studied after the determination of the project's risk level, in order to eliminate the potential risk of accident.Then this paper carried out the BLCD multi-objective analysis, from six aspects such as economic, aesthetic, ecological, performance and maintenance of custody and the service life. And after combining the geographical position, function, social factors and AHP hierarchy model, it selected the evaluation attributes with the expert questionnaire, and then the BLCD evaluation system and multi-objective decision model were both established. The convetional comprehensive weight model was researched and improved by the thought of Game Theory combining fuzzy subjective weight with objective weight on intuitive fuzzy entropy. Thus the attributes' information of each design can be expressed as a triangular fuzzy number, by the comprehensive weight vector. Finally fuzzy number geometric sorting method in decision-making was introduced to select the optimal design, to ensure the realization of the goals in bridge engineering.