Girder Bridge Structural Capacity Reliability Assessment Study

If the structure reliability of the used bridge is analyzed and its current and future reliability level on bearing capacity is presented, it will profit the highway development and administration department in making an economic and reasonable decision on the maintenance of the used bridge.In this dissertation, the structure bearing capacity reliability of the used reinforced concrete beam-bridge is researched by Structure Reliability Theory.First, the system reliability analysis method of beam-bridge is presented based on the failure model of main beam, which is the most important failure model of beam-bridge. This part includes the following four points. The control sections of main beam in the analysis of bearing capacity reliability are determined according to the appearance-damage survey and structure force analysis of beam-bridge. The representative failure models of main beam are searched by incremental method and disadvantage loading in the control sections. The equal-substitute beam method is applied, which can simplify the reliability estimation on bearing capacity of beam-bridge. And the state function on bearing capacity reliability of beam-bridge is presented and the structure resistance theory (or design) probability model in state function is deduced. Secondly, the load action theory probability model of beam-bridge is researched in this dissertation, and also the load action effect theory probability model. Thirdly, the structure resistance theory probability model and the load action effect theory probability model are amended according to the main-beam's damage and load condition of the used beam-bridge. Thus the structure resistance assessment probability model and the load action effect assessment probability model of the used beam-bridge are deduced in this way and they are practical. Lastly, the structure reliability assessment index on bearing capacity is calculated by JC method. Thus, the structure bearing capacity reliability of the used beam-bridge is evaluated in the above way. And the numerical example shows that this method is accurate.The structure reliability assessment model on bearing capacity of the used beam-bridge is established for the further research.