Research On The Influence Of Data Quality On Identification Of The Health Status Of Large-span Bridges

The research object of this subject is the health status identification of the support cable of the long-span suspension bridge.Based on the Suspension bridge finite element model,the effects of different quality strain data generated after random measurement error and model deviation on the health status identification effect of the hanger or main cable anchorage area with random damage degree within 30% were mainly studied.The main research content of this paper includes the following aspects:First,the structural response parameters were performed.Analysis of the rate of change of axial strain in the presence of damage to the supported support cable,it was found that the rate of change of the axial strain of the the support cable was changed significant when the support cables were damaged.So,the axial strain was selected as the structural response parameters to carry out the follow-up research on health status identification.Secondly,health status identification under random measurement error was performed.Through the research on the health status identification of the suspension bridge after the randomm easurement error,it was found that when the standard deviation of random measurement error was 0.5%,the interference to the strain was relatively small and can be effectively identified.When the standard deviation was 0.75 % and 1.5%,the health status identification failed.Next,health status identification under model deviation was performed.The research on the health status identification of suspension bridges after prestressing deviation and damage to the key parts of the main tower as well as stiffening beam was carried out.Effective health status identification can be made for the suspension bridge,when the standard deviation of the prestressing deviation was 5% alone or the standard deviation of the damage of the main tower and the stiffening beam were 5% and 10%,or the combined effect of the standard deviation of the damage of the main tower and the stiffening beam and the prestressing deviation were all 5%.Then,the health status identification method correction under random measurement error was carried out.Considering the random measurement error can be mitigated by taking the average after multiple measurements.Thus,the health status identification of the suspension bridge after the random measurement error continues to be studied by this way.When the standard deviation of the random measurement error was 1.5%,after more than 10 times of data acquisition and processing,effective health status identification can be made.When the standard deviation of the random measurement error was 3.75% or 2.5%,effective identification can be performed after 30 times of data acquisition and processing.Studies have shown that increasing the number of data acquisition and processing can effectively reduce the adverse effects of strain data under random measurement error on health status identification.Finally,health status identification under comprehensive error was performed.The research on the health status identification of suspension bridges under the combined action of random measurement error and model deviation was carried out.After 30 times of data acquisition of the random measurement error and the standard deviation of the random measurement error level was 1.25%,the standard deviation of the prestressing deviation was 5%,and the standard deviation of the damage of the main tower and the stiffening beam was 5%,the strain has some bad effects on health status identification.However,these effects were not sufficient to interfere with the effectiveness of health status identification.