Standardized Evaluation Method Of Service Status Of Heavy-haul Railway Bridges

With the rapid development of railway transportation in China,following the high-speed railway,Heavy-haul Railway has become the new focus of railway transportation development due to its advantages of high load,high density,energy conservation and environmental protection.The development of Heavy-haul transport in China can be divided into two modes: carrying out capacity expansion and transportation transformation for the existing conventional speed railway(increasing traction and operating density on the basis of medium-live load design to increase traffic volume)and increasing axle load(27-30 t);New dedicated Heavy-haul freight railways.At present,the main development mode is expansion and reconstruction.With the existing railway transport capacity of further development,more and more railway bridges' structure performance degradation is increased because of the increase of axle load and under the influence of factors such as environment for a long time.it's becaming a top priority to develop a method for evaluating the comprehensive state of the structure of Heavy-haul Railway bridges in service.In this paper,the standardized evaluation method of service status of Heavy-haul Railway bridges is taken as the main research direction.The main research contents and conclusions are as follows:(1)The six sub-items for evaluating the service status of Heavy-haul Railway bridges are defined,which are preliminary investigation and assessment of bridges,risk source inspection and assessment,structure deterioration assessment,special parameter detection and assessment,operation performance test and bearing capacity calculation assessment.The respective weights and rating criteria were determined.(2)The risk sources of Heavy-haul Railway bridges are divided into three categories: general risk sources,major risk sources and disaster risk sources.(3)The evaluation of structural deterioration of Heavy-haul Railway bridges is defined,and the evaluation indexes and scales of longitudinal displacement of beam body and eccentricity of line beam are added on the basis of the evaluation of structural deterioration of existing bridges.The related evaluation index and scale of bearing disease were added.The evaluation index and scale of deterioration of anti-falling beam are added.(4)A method for checking the bearing capacity of Heavy-haul Railway bridges based on structural deterioration and special parameters detection is proposed.The method can quickly and effectively evaluate the bearing capacity of Heavy-haul Railway bridges without load test or affecting normal railway transportation.(5)Taking a bridge of Heavy-haul Railway as an example,a complete standardized evaluation of its service status was carried out,and the weight of the method based on structural degradation and special parameter detection was determined through static load test,which verified the feasibility of the method.