Theoretical Research On The Preventive Maintenance Technology Of Concrete Bridge

Bridge preventive maintenance, with lower life cycle cost, can make bridge provide the high-quality service for a long time and prolong service life, etc. Bridge preventive maintenance work has been carried out since the 90 s in our country, however, the progress of bridge preventive maintenance study is slow, further more, applications in the practical engineering are also less. For the problems of lacking of guidance for bridge preventive maintenance practical use, unclear understanding between bridge corrective maintenance diseases and preventive maintenance diseases and inadequate decision-making basis of maintenance time, this paper studies the main type of bridges-concrete bridges, in order to improve the bridge service life and reduce maintenance cost.If concrete bridges are implemented the preventive maintenances, it is necessary to confirm the process, object, and time of preventive maintenance. For the problem that preventive maintenance process is not clear, this paper, combining with the characters of preventive maintenance, sets up the process of bridge preventive maintenance and lists the steps of birdge preventive maintenance on the basis of corrective maintenance. For the problem of unclear understanding between bridge corrective and preventive maintenance diseases, from the perspective of the durability of concrete bridges, the paper summarizes common diseases which influence the durability of concrete bridges, and uses the way which can evaluate the technical condition of bridges in "Standards for Technical Condition Evaluation of Highway Bridges" (JTG/T H21-2011) to evaluate the technical condition of bridge which is under the influence of a single disease, so we hereby confirm the severity of disease and sum up the common concrete bridge diseases of preventive maintenance in "Standards for Technical Condition Evaluation of Highway Bridges" (JTG/T H21-2011). For the preventive maintenance time of bridges, from the perspectives of the degradation of bridge technique condition and life-cycle maintenance cost, this article adopts Markov theory which simulates and forecast the degradation rule of bridge technique condition to confirm the rough timing of preventive maintenance, and uses the method of calculating the final value of maintenance cost which considers technical condition degradation and time value of money to determine the timing of preventive maintenance when the life-cycle maintenance cost is lower.With reference to the relevant data of technical condition of bridges in an area, on the basis of appropriate adjustments, this paper uses the Markov model to calculate and get the Probabilistic Transfer Matrix of the technical condition of bridges, then the probabilistic distribution vector in any year can be calculated. Afterwards, the paper adopts the predicted method of maintenance cost to calculate the cost of three maintenance ways, including one-time maintenance and periodical maintenance with period T= 5, T= 8. Finally make a comparison among the life-cycle maintenance cost of the above three ways, so the better preventive maintenance timing can be confirmed. In this paper, the theory of concrete bridge preventive maintenance is studied, and the theory has guiding meaning on the actual projects of concrete bridge preventive maintenance.