The Detection And Evaluation Of Continuous Box Girder Bridge Base On Nondestructive Testing And The Study On Strengthening Optimization

Based on the conclusion of study on the related research at home and abroad,this thesis studies on the disease detecting,the assessment,the reinforcement program optimization and the final preferred reinforcement—the technique of bolting steel plates, which depending on the process assessment and reinforcement of a long-span continuous prestressed box-girder bridge, in accordance with the main line of detection, identification,assessment and reinforcement of continuous prestressed box-girder.The main research as follows:1. It has formulated appropriate detection schemes aim at the complex actual situation of this bridge.In order to get the real disease of the bridge,It has put forward the way of combining the GPR detection and sample-drilling method with the nonmetal ultrasonic detector, the engineering intelligent crack detector and other advanced instruments to preliminary and detail detecting a long-span continuous prestressed box-girder bridge.Through core sampling method,it verify the non-destructive testing of ground penetrating radar has good practicability.Based on the test result, the durability of the single component( bottom plate) and whole of present bridges has been assessed and determine the need for the reinforcement local in the closure of the cross-section of bridge.2. Based on the results of detection, with the finite element analysis software-MIDAS and local analysis of the bridge, the causes of disease of bottom plate of box beam has been discussed. the conclusion that between the reinforced coating of backplan and reinforcement fabric in web reinforcement is not formed the effective force as a whole framework, which Will weaken the resistance of the bottom plate, making cross-segment of closure increases the possibility of bottom plate collapse.3. In determining the need for strengthening the bridge, it's necessary to rapidly and accurately determine the optimal reinforcement of the program, With the relative membership degree theory of Fuzzy Mathematics and combined with analytical hierarchy process in which quantitative analysis are main and qualitative analysis are lesser,drawing the relative membership degree of optimized strategy model. On these bases, the fuzzy optimum selection model of bridge consolidation is builded.Finally, through an example demonstrates established model is reasonable and practicable.4. It has analysed the stressed characteristics and the principle of design of chemical anchor steel plates which is the optimized way. Based on the specificity of bridge strengthening program and taked into account the effect of structural adhesive, the formula about calculating a norm al section intensity and the cross-section strength has been given.Also, it has discussed the computing method about the ultimate bearing power of the cinch steel and carried out the strength effect of using the technique of bolting steel plates.