| The expansion joint disease of large bridges is a common problem in the daily maintenance of bridges,and may adversely affect the overall function of the bridge.Using the measured data of the bridge health monitoring system to evaluate the service status of the expansion joints is one of the key issues in the damage assessment of the bridge structure.Based on the health monitoring data of a real bridge,this paper considers the uncertainty relationship between the displacement and the temperature of the expansion joint,establishes a Bayesian linear model between the displacement and the temperature,and further proposes the expansion joint damage assessment method to carry out the damage of the bridge expansion joint Work with reliability assessment.The main content has the following aspects:(1)Establish a Bayesian linear model between the displacement and temperature of the expansion joint and determine the model parameters.Based on the measured data,a probability model conforming to the uncertainty relationship between the expansion joint and the temperature is established,and the Bayesian estimation value of each parameter in the model is solved by the MCMC method,and the probability model of the displacement under the action of temperature is obtained.(2)Propose a method for judging damage when the expansion joint is blocked.Based on the Bayesian linear model,firstly,the mean value control chart is used to determine whether the structure is abnormal,and then the damage type of the expansion joint is determined based on the change characteristics of the measured displacement curve,and finally the corresponding relationship between the damage degree and the initial temperature when the abnormal displacement data appears,Assess the degree of damage to the expansion joint.By simulating the situation of different degrees of damage,it is verified that the proposed method can be used to judge the degree of damage when the expansion joint is blocked.(3)A damage identification method for abnormal displacement data of expansion joints caused by abnormal bearing restraint is proposed.Firstly,the mean value control chart is used to judge whether the structure is abnormal,then the damage type of the expansion joint is judged based on the change characteristics of the measured displacement curve,and finally the damage location of the support is judged based on the change characteristics of the abnormal data.By simulating abnormal data in different situations,the effectiveness of the proposed damage identification method is verified.(4)The reliability analysis method of bridge expansion joints is established using reliability theory.Based on the Bayesian linear model,reliability indicators and abnormal indicators are established,which can be used to evaluate the reliability of bridge expansion joints.In this paper,the damage assessment and reliability analysis methods of bridge expansion joints are established to provide theoretical and technical support for the operation and maintenance of expansion joints during the service period. |
