THE REMAINING SERVICE-LIFE PREDICTION OF A REINFORCED CONCRETE GIRDER BRIDGE BASED ON TIME-VARIANT RELIABILITY

摘要

The reliability of civil infrastructure such as bridge is time-variant,and the resistance of the bridge structure will gradually become in decay with service time increasing. This is due to performance deteriorating and time-variant mechanical and environmental loadings. The main objective of this paper is to present the remaining service-life prediction method for the reinforced concrete girder bridge based on the time-variant reliability. Firstly,based on the statistical analysis of the vehicle loading data from the toll stations,a stochastic process model of vehicle load was constructed. The time-variant distribution of the maximum total load effects during a given assessment period was also extracted from two kinds of vehicle operation states,including normal operation and coarctation operation while combining the normal distribution model of dead load effects. Secondly,the time-variant rules of reinforced concrete girder bridge resistance rating were explored under integration actions of various factors as well as failure modes of real structural system. The probability prediction models of flexural resistance of concrete girder bridge were studied,and the remaining service-life prediction method was then proposed based on the time-vairiant reliability. Finally,Songkou Bridge before and after strengthening was selected as engineering background to conduct time-variant reliability analysis. Based on the minimum target reliability index of 0. 85/3,the remaining service-life of Songkou Bridge before and after strengthening are 10 and 43 years respectively. This kind of analysis can be used as the reference of the structural health monitoring,safety evaluation,and the decision-making of maintenance planning of existing bridge structures.