Research On Optimum Maintenance Decision Of Concrete Girder Bridge Structure In Service

As an important component of modern transport, girder bridge plays a very important role in China's economic construction and social development. The safety and reliability of these structures has a critical influence for on the normal service and efficiency of transportation, as well as the traffic capability. Due to inappropriate construction and mismanagement, many girder bridges in China appeared varying degrees of damage too early. And it is a great risk for the transport operation. Then, the girder bridge faced with many questions, such as repairing or not, major repairing or minor, even removing or repairing, et al..Based on domestic and foreign research previously, this paper adopt the minimum annual average cost during strengthening life to optimum maintenance decision-making, according to the structural reliability theory and the structure maintenance theory, along with the optimization theory. The major researches are listed as follows.(1) The current domestic and foreign research are systematic detailed, and the objective of this research have been are illustrated;(2) The relationship between strengthening degree and life-cycle are presented, as well as that between difference value of reliability index deterioration rate and life-cycle. The prediction methods based on the strengthening degree and the difference value of reliability index deterioration rate are recommended;(3)The costs and the benefits of the girder bridge in the strengthening life-cycle are analyzed, and the overall objectives and economic goals of the girder bridge in the strengthening life-cycle are proposed. The relationships between the strengthening degree and the strengthening cost are established;(4)The failure levels of the girder bridge structure are divided, and the computing method are detailed incorporated with the loss components;(5) The current strengthening maintenance methods of the girder bridge are systematic elaborated, and the maintenance guideline has been presented. The optimal decision-making model based on the average annual cost has been proposed;(6) Combining with a practical project, the feasibility and applicability of the model are studied. It is available for reference in the bridge maintenance work.(7) The results this thesis are summarized, and further research in this area is prospected.