Research On Bridge Safety Early Warning Based On Statistical Analysis Of Time-frequency Domain Features Of Monitoring Data

In order to ensure the safety of the bridge,grasp the health status of the bridge in real time,and avoid unexpected accidents,many bridges in the world have applied health monitoring systems,but the collected data is based on statistical analysis of time-frequency domain characteristics.There is very little research on safety early warning.Therefore,discussing the alarm methods based on the statistical analysis of the time-frequency domain characteristics of the monitoring data has an important guiding role in the development of the entire bridge health monitoring system.Based on the statistical analysis of monitoring data,this paper studies the safety early warning methods of bridges.The main research contents and results are as follows:(1)For the collected actual acceleration data,use MATLAB program to write a time series ARMA model to model it,and then analyze the stability of the built model and the damage sensitivity of the extracted early warning indicators.The results show that the model parameters of different monitoring data are less affected by the environment and other interference factors.When damage occurs,the model parameters will fluctuate to a certain extent.The damage simulation conditions also verify the sensitivity of the parameters to the damage.Therefore,the first three-order parameters are used to construct the characteristic indicators of safety warning,and the corresponding safety warning process is given according to the numerical simulation.Finally,the actual data analysis verifies the effectiveness of this method.(2)The similarity measurement methods and data transformation theory applied to monitoring data are sorted out,the feature display of the original series is constructed based on the transformation of vibration data,and the distance function index is used to measure the similarity,including Euclidean distance,correlation coefficient,etc.parameter.Furthermore,the phases generated by the moving load of the bridge under different damage conditions are simulated by numerical simulation,and the above-mentioned characteristic indicators are used to give safety warnings to their damage conditions,so as to illustrate the effectiveness and accuracy of the application of distance function indicators.(3)Summarized the safety early warning method based on the energy spectrum index constructed by wavelet packet analysis,and compiled a safety early warning program based on the energy spectrum using MATLAB;further established a numerical model to verify the early warning effect of the energy spectrum early warning index,and the results showed that the constructed the indicator has a good application effect.(4)According to the early warning characteristics of the structure,the preliminary design of the bridge multi-index early warning system concept based on the statistical analysis of the time-frequency domain characteristics of the monitoring data is proposed,and the early warning level is divided into different levels according to the setting of the index threshold to achieve the Early warning purposes of varying degrees of injury.