Time-dependent reliability assessment of existing concrete bridges including non-stationary vehicle load and resistance processes

摘要

It is well known that existing concrete bridges are time-varying working systems, and the corresponding maintenance strategy should be planned according to the time-varying service performance. In this work, a time-dependent reliability assessment procedure is proposed while including the non-stationarities of the vehicle load process and resistance deterioration process simultaneously, which are the two factors that significantly influence the time-varying service performance of a bridge structure. To achieve this goal, the following key tasks are conducted in sequence: (a) extreme value modelling of non-stationary vehicle load process; (b) model establishment and updating of non-stationary resistance deterioration process; (c) determination of target reliability index of a concrete bridge component in the operation stage; (d) performing time-dependent reliability analysis while considering the non-stationary properties. In addition, a case study is conducted to illustrate the application of the proposed procedure by considering an existing concrete bridge as an example. It is found that the proposed time-dependent reliability assessment procedure is feasible, and some critical information on the time-varying service performance of the existing concrete bridge component can be obtained, which can be further referenced in the planning of the structural inspection, management and maintenance, etc.