The Disease Mechanism Analysis And Reliability Evaluation Of In-service Reinforced Concrete Girder Bridges In The Dry And Cold Regions Of Northwestern China

Bridges,as important nodes and hubs of the transportation system,play an irreplaceable role in transportation.Their carrying capacity and capacity are the key to ensuring the normal operation of traffic.In the process of use,the bridge will be affected by increasing loads,defects in the material itself and the natural environment,which will cause different degrees of damage.The continuous accumulation of these injuries will inevitably affect their normal use.Especially in the dry and cold areas of China,the bridges in this area are severely endangered by the harsh environment such as cold,dry,large temperature difference between day and night,which seriously endanger the bridge's health.At present,the evaluation of the reliability of concrete beam bridges in dry and cold areas mainly focuses on scoring experts based on the detection of various components,lacking judgment on the influencing factors,and the evaluation is more subjective.Therefore,it is necessary to conduct an objective and accurate comprehensive evaluation of the reliability of concrete beam bridges in dry and cold areas,so as to provide a scientific basis for the maintenance and repair of bridges in this area.The main research object of this paper is the concrete beam bridges in service period in dry and cold areas.By selecting 325 concrete beam bridges in Gansu Province for disease investigation,the main diseases affecting the health status of the active beam bridges are determined.And analyzing the samples,the disease conditions approximately obeyed the normal distribution,and further verified by the D-test method for large sample occasions.It was proved that the disease degree of the beam bridges in the dry cold region was roughly Normal distribution.On this basis,the disease mechanism of the main diseases of the concrete beam bridge in dry and cold areas is analyzed.Then,construct the reliability evaluation index system of the concrete beam bridge with the environmental characteristics of the dry and cold area,determine the reliability evaluation level of the active beam bridge with reference to the limit values of each index stipulated in the relevant standards and codes,and meet or fail to meet the main components Existing standards or specifications have formulated maintenance and reinforcement strategies with corresponding evaluation levels.Through analysis and comparison of various evaluation methods,an evaluation model of concrete beam bridge based on improved similar weight matter-element extension is established.Through the conversion of matter-element,a matter-element system for the reliability evaluation of beam bridges in dry and cold areas is constructed,and the improved similarity weight is used to determine the objective weight of the matter-element index.Obtain the comprehensive correlation degree and ranking of the reliability evaluation level of the beam bridge to realize the comprehensive evaluation of the beam bridge.Finally,this model is used for example analysis to verify the feasibility and practicability of the model,and then provide a theoretical basis for the reinforcement and maintenance of beam bridges in the area.