Reliability-based Durability Study Of Sea-crossing Concrete Bridges

In recent years, more and more bridges across the sea are building or have been built with the development of the traffic, while the problem of the reinforced concrete structure's invalidation of the durability has become an international problem and puzzles the engineers. Especially in the marine or adverse environment, the problem will be more prominent. The bridges across the sea cost much and affect the national economy and the people's standard of living greatly. So the "the short-lived project " due to the lack of the durability will bring about an immeasurable loss to the country. This thesis discusses the durability of the reinforced concrete structure of the bridges across the sea from scene detecting, the evaluation and analysis of the durability, the surplus life time forecast to the optimization design. The main work is described as follows:(1) This thesis introduces the important significance, contents and research present situation at home and abroad of the bridges across the sea.(2) Based on the former research, this thesis discusses the rustiness theory of the reinforced bar due to chlorine ion's corrosion afresh and discusses the main influencing factor of the reinforced bar's rustiness in the marine environment. The rustiness theory and the infiltration model are discussed especially. A rustiness model in the marine environment is established and the effect on the reinforced bar'mechanics capability and carrying capacity is described. Some related method to deal with the rustiness in the marine environment is proposed based on the existing method.(3) The evaluation rules of the reinforced concrete structure in the marine environment are proposed according to the rules in the ecumenical environment. This thesis discusses the Monte Carlo's application in the reliability's analysis, proposes the method calculating the resistance's factors of the RC eccentrically loaded short column and reinforced concrete bending member by the Monte Carlo so that the analysis problem of reliability can be settled well. The random resistance's model of the reinforced concrete eccentrically loaded short column and reinforced concrete bending member in the marine environment is established to analyse the structures'durability in which the analysis by the method of reliability of respective influencing factor is the emphases.(4) This thesis adopts the Tieshangang Bridge in Guangxi province as the project background, analyses the main factors affecting the durability of the bridge according to the scene detecting data, evaluates the durability of its piers and 30m-span girder based on the reliability, educes the time-dependent reliability and proposes some theory for the durability's evaluation of the congener bridges.