Concrete Continuous Girder Bridge Operational Safety Performance Assessment Experiment Research Based On Model Modification

Bridge is traffic line choke points, related to the development of national economy, so the operating safety of the bridge is very critical. At present, the first after the simply supported continuous prestressed concrete continuous girder bridge for construction technology is simple and mature technology, short construction period, as well as good structural integrity and is widely used in highway and city road in our country. In order to fully ensure the safety of existing Bridges can run, must be real technology condition to make scientific and rational assessment of the work. Finite element model updating method can make up for the inadequacy of bridge structure static and dynamic load test, the revised model can better reflect the real working state of the bridge as a whole as well as the force of the local component. Based on this, this paper proposes a model based on modified concrete continuous girder bridge bearing capacity evaluation method.This paper, taking the victory to the datong Shanxi Province an expressway on the engineering background of a viaduct, combined staticand dynamic load test data to carry on the finite element model of bridge structure modification, the revised using the finite element model of the actual operational safety performance and the strength of the under standard load to evaluate the safety stock. In this paper, the main research work is as follows:1.The static and dynamic load test on site of the bridge, the deflection and strain values each measuring point and vertical first six order natural frequency of vibration of bridge structure. Based on the design drawings 1 league 7 across prefabricated prestressed concrete continuous box girder bridge of the shell element model and grillage model. Demonstrates the grillage model mesh reasonable form and equivalent stiffness method.2. On the premise of using the correction method of dynamic and static load model and a dynamic weighting coefficient, based on the parameter sensitivity analysis, the method of selecting high sensitivity of the parameters as design variables of model correction, with real bridge structure static load test of vertical deflection and dynamic test of each control section of the vertical first six order natural frequency of vibration as the static and dynamic respectively the objective function of state variables, and then combined dynamic and static target function structure combined objective function, based on grillage initial finite element model of the construction of bridge design data for model updating. Andthen according to the same as the bridge static test of vehicle load and load arrangement, adopt the method of numerical load to simulate the finite element model of the revised loading, to calculate the strain values, each test section deflection value, and comparing with the bridge static test data, and calculate the relative error between the two, combination of design variables and state variables numerical again, the effect of the comprehensive validation model correction.3.Based on the finite element model of bridge revised model, using the same as the test vehicle load level of load and load arrangement to carry on the numerical simulation, calculates the point of the bridge deflection, strain, and compared with the measured data, and put forward a model based on the basic concept of the generation such as calibration coefficient of correction, based on the model is verified by test generation such as calibration coefficient of correction to assess both the prestressed concrete bridge operation effectiveness and accuracy of safety performance.4.Based on the finite element model of bridge revised finite element model, using bridge design level of vehicle load, and using the method of numerical load, load calculation, calculate the actual structure of the bridge carrying capacity coefficient, and then USES the actual structure of the bridge bearing capacity coefficient of quantitative analysis of both the strength of the bridge structure under current outside load securityreserves, assessment of the structure of the residual bearing capacity.