The Study Of Bearing Capacity Evaluation Of Bridges Based On The Dynamic Model Modification

With the rapid development of economy in China,A provincial highway as the main framework of the highway network has basically taken shape,at the same time the bridges along in which play a very important role.However, because of the increasing present traffic volume by a wide margin, as well as the improving traffic density and vehicle load,the existing highway bridges that designed base on the original design standard can’t meet the requirements of normal use and severely restricted the development of the transportation industry.In order to ensure traffic safety or improve the current load level,it is particularly important to evaluate the bridge bearing capacity,at the same time also for old bridge for prolonging the service life of reinforcement and reconstruction measures provides a reliable basis for calculation and analysis.This paper adopts grillage method using beam element set up multi span continuous girder bridge model,using of the measured modal parameters(frequency,mode of vibration) and dynamic finite element model to calculate the corresponding value of the residual constructed the goal function,using ANSYS optimization algorithm for the model geometry density elastic modulus of correction, target function has minimum value. After optimization of finite element model and the modal parameter value and measured value are basically the same,namely model after correction of the finite element model can better reflect the actual mechanics of the bridge condition.By utilizing the optimum model for the section bearing capacity of the bridge is about the actual bearing capacity.In this article, the main completed includes:(1) Introduced the theory of finite element model correction and the commonly used method of optimization model.(2) Introduces domestic and international current situation of bridge and the meaning of the evaluation of bridge, At the same time introduces the commonly used evaluation methods both at home and abroad and its research present situation and the development tendency, and has developed a set of bearing capacity based on the bridge bearing capacity evaluation methods.(3) Modal test of motive power for Hansangou Bridge,get the modal shapes and frequencies.(4) According to the design drawing,establish the finite element model,get the initial mode shapes and frequencies. (5) Using ANSYS software to initial model optimization,make the calculation frequency and vibration mode approach in the measured value.(6) For fixed good model of load effect and the calculation of bearing capacity and complete the bearing capacity evaluation..