Prestressed Concrete Bridge Structure Damage Assessment Research

In engineering, it is circumscribed that the damage assessment and reinforcement analysis for the existing bridge structure generally use the experimental test and the finite element modeling analysis. Especially, in the finite element modeling, all kinds of hypothesis to the real structure causes the error between the finite element model and the actual structure, so that calculation value can’t well consistent with experimental measurements. It increases difficulty for the bridge condition assessment and the remaining life prediction.Therefore, to amend the finite element model and improve the modeling accuracy for the existing structures has always been the hot spot of study. At present, the generally accepted and feasible method is to amend the finite element model by use of integration the experimental test results with computer simulation. According to the above, in the paper, the initial ANSYS finite element model for the structure is established. Combined with the actual bridge structure test result, the sensitivity of structure parameters is analyzed, and the major correction parameters are gained. By means of the parameter estimation technology of first-order search optimization theory in the ANSYS optimization module, the initial finite element model is corrected strategically. The feasibility and effectiveness are compared with different finite element correction technique. Putting the revised finite element model as the baseline model, the bearing capacity evaluation and reinforcement analysis of the prestressed real bridge are investigated. Analysis results show that the method proposed in the paper can be used for the health state evaluation of prestressed concrete bridge structure. The main research work is as follows:1.Based on the load test of the on-site large prestressed concrete girder bridge, the main girder and the connecting components of bridge are detected. The bridge actual operation data is gained by means of the static test, the dynamic test and other means. According to the direct damage information resulted from the preliminary diagnosis analyze, the basis data is provided to establish ANSYS damage numerical model.2.According to test results of the real bridge, the parameterized finite element model is set up. Trying to adopt the targeted correction strategy, and using the first-order optimization search algorithm, the finite element model of the test components is updated respectively based on the static test, the dynamic test and the combined the static and dynamic test. Being Compared the model updating efficiency and effectiveness of different methods, introducing the selection of optimization method, and it is pointed out that the finite element model updating is a highly specific technology, almost no a general algorithm can update. Therefore, the appropriate corresponding updating method should be developed for different types of engineering structures, as far as possible to obtain relatively accurate updating model.3.Considering that the mechanical characteristics of long-span prestressed concrete bridge structure is influenced by more factors than normal one, the artificial intervention is bigger in updating parameter selection, the stability and applicability of the updating result of the traditional finite element is bad. In the paper, the finite element model updating is tried based on the ant colony optimization algorithm by which the complex, uncertain and nonlinear problems can be well solved. It provides a new train of thought for the finite element model updating of large structure.4.Relying on the existing prestressed concrete bridge, Putting the revised finite element model as the baseline model to access the bearing capacity of this bridge. Result shows that the real stress state of the bridge can be more accurately reflected by using the revised finite element model. This model can be used to the damage assessment and recognition of the prestressed concrete bridge structure. On this basis, the reinforcement scheme on serious damage structure parts is put forward, and then the finite element model for the reinforced structure is established. The effectiveness of the method is verified by comparing the bearing capacity of the bridge before and after which is reinforced.