Dynamic Reliability Evaluation Of Existing Prestressed Concrete Bridge Based On Bearing Capacity

Along with the increasingly development of evaluation, maintenance and reinforcing for the bridge structure, it is a major direction to prestressed concrete Bridges in service capacity evaluation which based on reliability theory. Along with the development of prestressed concrete Bridges, It has great significance to improve the bearing capacity of the existing Bridges on which we conducted detection and reliability evaluation. We take a continuous girder bridge in Hebei province as analysis object, and then calculate the reliability of the upper structure in three failure modes(bending, shear and stress limit).At last, give the corresponding conclusion of the capacity assessment. The specific content is as follows:Firstly, from the main ingredients of bridge structure, introduces the index requirements of every material in specification, and through the collection and analysis of relevant test data, draw the sensitivity of the main parameters on bearing capacity,such as concrete strength,the area of common reinforced and prestressed reinforced.Secondly, in the basis of reliability theory, discusses the reliability characteristics on the existing prestressed concrete bridge,then confirms two failure criterias of the bridge component which are carrying capacity limit state and normal use limit state; Base on the combination of neural network technology and the response surface method, according to literature statistics to prove it works, and summarizes the process of reliability calculation.Thirdly, in using the continuous girder bridge, as the materials own aging and external environment factors, structural resistance is continuously cut over time.For this reason, the parameters measured in different time with structure resistance are differents. In addition, with overload phenomenon increasingly heavier and vehicles change, makes the load effect is changing too. According to the existing research results, get resistance and load effect random process model of bridge structure.Finally, establishs the link between reliable indicator and the rank deviation of bearing capacity assessment standard, puts forward that we should combine bridge capacity ratings with reliability division, so it can provide reasonable and effective basis for existing bridge reliability evaluation.In the ending part of this paper, makes a brief summary for research work, gives some research conclusions and based on the current research situation, points out the problems need to be further study and solve.