Study On Optimization Maintenance Program Of Bridge Deck Based On Life Cycle Cost

With the increase of traffic volume, vehicle load and the effect of natural enviroment, many bridges,which are built in our country in the last30years have different degrees of aging,so they need to repair and tetrofit. However, the national’s financial resources is limited,so the key of the trouble is how to use these limited funds reasonably,adopt the suitable program at the right time to save the cost.For economic analysis and optimization in bridge maintenance decision,there are lots of researches and achievements home and overseas for many years.But,the study of economic analysis and optimization in bridge maintenance decision is still in the primary and fundamental stage because of this study involved in bridge engineering,economics,computer technology and optimization technology.Based on such backgroud,this paper combines the life cycle cost analysis theory,raises the deterioration model of non linear-deterioration delay-non linear improvement.Then a in-depth research on optimization in bridge maintenance decision based on genetic algorithm is given.The main contents are as follows:(1)Summarized the basic theory and method of genetic algorithm, compared the concrete form of the different operation such as selection, crossover and mutation, analysed the relationship between genatic algorithm and other search technology, pointed out the advantages of genetic algorithm in solving optimization problems.(2) Studied on the engineering structure reliability theory and application of life cycle cost analysis theory in bridge engineering structure.(3)Studied on the deterioration model of engineering structure in the different state of repair,and discussed the advantages and disadvantages of straight and curve deterioration model.Based on the analysis of the existing model and actual engineering examples,proposed the deterioration model of non linear-deterioration delay-non linear improvement(consider the reliability index remains unchanged in a certain period of time after major maintenance),and the Markov theory is used to prove the deterioration model of non linear-deterioration delay-non linear improvement is more consistent with the actual situation than the linear or the linear curve model.(4)Based on the life cycle cost theroy and genetic algorithm, designed a suitabl algorithm for solving the optimization problem of the maintenance program. From the "maintenance","reinforcement"and"reinforcement and maintenance"three modes to solve the optimization problem,and calculate the two questions that control life to calculate the optimal cost and control cost to calculate the optimal life.Some beneficial conclusions are obtained.Through the example proves that method is reasonable and efficient.