Finite Element Model Updating Of A Flying-swallow-typed Tied-arch Bridge

Now,bridges are an important transportation hub for social development,and some large bridges even have significant economic and social values.Therefore,damage identification,health monitoring and safety assessment of bridge structures have become particularly important.Among them,the establishment of accurate finite element models is an important means to carry out a series of work.This paper takes a flying swallow-style arch bridge in Fuyang as an object.Based on the comparison and analysis with the measured data,the research and discussion of the finite element model modification are carried out by using the response surface method.The updated finite element model can more accurately reflect the actual stress characteristics of the arch bridge.The updated finite element model can be used in structural health monitoring and safety assessment,which has great engineering significance.The research results show that the finite element model modification based on the response surface method has the characteristics of high accuracy,smooth convergence and small amount of calculation,and can effectively improve the efficiency of the finite element model modification.The research results have certain reference value for the updated research of the finite element model of the bridge structure.The main work and conclusions of the paper include:1.According to the original design drawings of the bridge,the initial finite element model of the flying-swallow-type arch bridge was established using the finite element software ANSYS.2.Based on the tensile force of rod of the completed bridge,the iterative method is used to modify the tensile force of rod of the finite element model.After the correction,the error between the calculated value and the measured value of the tensile force of rod is significantly reduced.The error of all tensile force of rod is within 3%,and the maximum error decreases from 34.39% before correction to 2.29% after correction.The effectiveness of this method is verified.3.Based on the load test data,the finite element model was modified using the response surface method.According to the significance analysis of the elastic modulus,density and other parameters of the main components such as suspenders,arch ribs,main beams and diaphragms,it can be seen that the significant influence parameters mainly come from the main effects and secondary effects of the parameters.The updated results show that the parameter changes are within a reasonable range,and no more than 20%.4.The mechanical behavior of the updated finite element model is more consistent with the actual structure.The first-order vertical bending frequency error of the dynamic response was reduced from-14.64% to 2.23%.The deflection value error of the three measurementpoints of the static response characteristic quantity has been reduced to less than 20%,which is within an acceptable range for large bridge structures.5.Using two static load test conditions,the effect of measuring point deflection correction was tested.The deflection error of most measuring points is obviously smaller,indicating that the overall effect of the finite element model correction is better.The modified finite element model can reflect the mechanical state of the actual structure more realistically,and the finite element model updating based on the response surface can take better correction effect.