Assessment Method Research To Concrete Beam Bridges Health Conditions Based On Long-term Monitoring Data

Bridge is the throat of highway, its carrying capacity is also the key to connecthighway. In recent years, with the rapid development of national economy, bridge bearsthe heavy transportation task for a long time. So the security status of the bridgestructure is more and more attention by people. Regular check can’t sustainably andtimely grasp the security status of Bridges. And effective online health monitoring andsecurity status evaluation can provide structure safety with early warning, so as toprevent the happening of the major disasters and accidents.On the basis of theory and technology of bridge health monitoring and security statusevaluation at home and abroad, this paper takes long-term monitoring data of concretebeam bridge health status judgment method as a research key. It takes Yangtze RiverBridge health monitoring system as the project background. Based on theory of whichand engineering practice, a series technical issue on bridge health monitoring andsecurity status evaluation has been studied. The main contents and results are stated indetail as following:①F irstly, we discuss the goal and the significance of bridge structure healthmonitoring, and introduce the present situation of it and security status evaluationmethod research at home and abroad, analysis some problems of it at the current status．②T hispaper introduces the theory and method of time series analysis, provides anew train of thought for mass bridge monitoring data processing. Using MATLABmathematical tool, first of all, the bridge monitoring data preprocessing, and thenthrough data mining function of the time series, analysis of monitoring data in timeseries model. So as to achieve the prediction effect of monitoring data, that makes itpossible to bridge health warning.③Study temperature effectsof the real-time monitoring data, based on linearregression analysis of mathematical statistics, to find the relationship between thetemperature and the monitoring index, then date can be obtained which reflects thefeatures of bridge health state after eliminating the influence of temperature load.④Based on the analytic hierarchy process and variable weight synthesis principle,health state evaluation system and the index evaluation system of concrete girder bridgeare established. Firstly, this paper introduces the basic steps and the fundamental ofanalytic hierarchy process (AHP), and the calculation method of weighting is realized.Secondly the data between different monitoring index values can be evaluated throughdimensionless processing and grading evaluation of the underlying index. Usecomputational analysis of structure finite element model, the threshold of deflection andstress under load combination can be listsed. Found a way that is out of the artificialsubjective factors and relatively stable to constructed measuring point judgment matrixof stress and deflection. Finally this paper evaluates the safety performance of thebridge structure based on variable weight synthesis principle, it solves the issue thatmay affect the working state of the whole bridge due to the small weight and notobvious factors in total results.This method is applied to make evaluation results morereasonable.