Research On Component Rating Method For Health Monitoring Of Prestressed Concrete Cable-stayed Bridges

In the course of bridges operation, there are many potential safety hazard due to the external load, environmental erosion and material aging. By applying bridge health monitoring system to monitor the operation status of bridges in real time, potential dangers can be found out timely. Meanwhile, basis and support for decision making of bridges maintenance department can be provided by using monitoring information to evaluate the bridge health status. In bridge health monitoring, the manual inspection is an important supplement to the on-line automatic monitoring, which can monitor the items unmulched in the on-line automatic monitoring. However, the current manual inspection strategy is lack of scientific guidance and the formulating of manual inspection strategy rely on engineering experience, which makes the judgment subjective. Consequently, the cycle and the depth of the inspection for bridge components are short of reasonable discrepancy. Thus, neither the inspection of weak components will be distinctly constructed, nor the cost of inspection will be properly saved.In view of the aforementioned existing problems in manual inspection, component rating method for health monitoring of prestressed concrete cable-stayed bridges is researched in this dissertation. The method can rate the component and formulate a targeted manual inspection strategy for component and finally realize the preventive maintenance.The main work of this dissertation is as follows:(1) A literature review on the field of bridge health monitoring. The development history of prestressed concrete cable-stayed bridge is introduced. The development and application of bridge health monitoring at home and abroad are summarized. The structure of health monitoring system of Longwan bridge is introduced briefly.(2) The design objectives and principles of component rating system for prestressed concrete cable-stayed bridges are stated., and the overall framework of component rating system is proposed.(3) Research on classifying method of component for prestressed concrete cable-stayed bridges is implemented. The classification method of component is proposed on the basis of component types, component position and unit number.(4) Research on analyzing method of component rating factors for prestressed concrete cable-stayed bridges is implemented. Based on the characteristics of prestressed concrete cable-stayed bridges, safety factors, durability factors and the rating criteria are proposed to rate the bridge component. The analysis method of rating factors is also summarized and improved.(5) Research on integrating method of component rating matrix and developing method manual inspection strategy for prestressed concrete cable-stayed bridges is implemented. The weight of safety factors and durability factors is determined by using analytic hierarchy process method. On the basis of it, integrating method of rating matrix and relevant formulating method of manual inspection strategy is proposed.(6) Component rating method of prestressed concrete cable-stayed bridges proposed in this dissertation is applied to rate Longwan Bridge components. The component rating matrix of the bridge are obtained, and the manual inspection strategy of Longwan bridge are formulated according to the matrix.In this dissertation, In consideration of bridge safety and durability, component rating method for prestressed concrete cable-stayed bridges is researched. The method provides the scientific basis for manual inspection strategy formulating. The effectiveness of the proposed method is well validated by the application in the component rating of Longwan Bridge.