Study On The Test And Analysis Methods Of Bridge Structural Self-vibration Characteristics

Self-vibration characteristic parameters of the bridge structure is thecomprehensive index to reflect the overall structure of working performance, is thefoundation of the bridge structure dynamic analysis, is the important basis to evaluatebridge dynamic performance. Therefore, testing and analysis of the natural vibrationcharacteristics has the important status in the structure performance evaluationsystem.However, the vibration form of the bridge structure has complexity andrandomicity.Current study on natural vibration characteristics of evaluation index is alsoat the exploration, has not formed the perfect system and unified standard. On the otherhand, the result of natural vibration parameters is affected by many factors, such as thetest method, test results analysis and data processing method.In Engineering practice,the vibration parameter identification precision is low, even you can see phenomenon ofmisjudgment. In this paper, through theoretical analysis, and combined with scene test.Aim at the limitations and deficiencies of the existing test analysis method, Throughstatistical analysis the sample and test methods. On how to improve the bridgeself-vibration test method, the reliability of the data processing method,as well as howto effectively use the measured data to judge the correctness of the results, and otheraspects to spread out study and analysis.At first, this paper points out that the arrangement of measuring points in thepresent situation of natural vibration characteristics test blindness, test method lack ofpertinence, parameter setting is not reasonable, the writer give the improvesuggestions.Discusses the optimization of the natural vibration characteristics testmethod, at the same time with real bridge as the object, the natural frequency ofvibration test, analysis of the test sample frequency settings make the acquisition ofsignal distortion, and puts forward reasonable suggestions on the sampling parameterssetting.Second, the author discusses the natural vibration parameters test data processingmethod, a quantitative analysis for time domain method in this paper, the results of thecalculation of the size of the sampling frequency of the measured frequency effect, anddiscusses the average cycle on the improvement of the precision. The frequency domain method in this paper, based on average method of energy project identification ofdamping ratio, further,the influence of different time with the result of calculation ispresented. At the same time using the half power point method to identify the dampingratio, in order to improve the frequency resolution, statistics of the number of differentspectral lines on the analysis result.Finally, this paper quantitatively analyze the relationship of stiffness and frequencybetween the theoretical calculation and the actual test.Put forward according to thestructure of the field measured frequency, obtained by the change of the structure of theactual stiffness and stiffness, evaluate the structure performance.Analyzed on the basisof the measured damping ratio on the structure performance evaluation has certainreliability, and statistical analysis of the damping ratio and impact coefficient ofcorrelation.