Research On Safety Monitoring Technology Of Railway Steel Structure Overhead System

The railway steel structure overhead system is widely used in the reinforcement of railway bridges in coal mining subsidence areas.The failure of the joint of the steel structure overhead system will not only affect the safe operation of the train,but also threaten the safety of people’s lives.Aiming at the safety monitoring of railway steel structure overhead system,this paper proposes a set of dynamic strain monitoring and analysis methods using theoretical analysis,numerical simulation and in-situ monitoring.This method can be better used for safety monitoring of the railway steel structure overhead system.(1)In order to in-depth study of the problem of measuring point arrangement for safety monitoring of railway steel structure overhead system,this paper firstly starts with the load sharing law of the beam of the structure along the bridge,uses structural mechanics to carry out theoretical analysis,and combines numerical simulation methods in deeply analyzing its force characteristics,and obtaining the law of the load sharing percentage of the beam along the bridge direction.It provides the theoretical basis for measuring point layout,and gives the reference position for measuring point layout.(2)In order to solve the problem of damage identification and optimal layout of sensors,the structural dynamics part of Ansys was used to carry out numerical simulation tests of the structure under operating conditions.Researching dynamic response characteristics of the axial stress and vertical displacement at different positions of the beam under the different combining forms of node failure.The analysis found that the axial stress response of the beam under the track is smaller than that of the one close to the support.When there is no node failure,the axial stress time-history signal waveforms are "inverted mountain" and "parabolic" respectively;when a node fails,the waveform diagram and the maximum increase of the axial force-response time history curve at different measuring points of the beam will change accordingly.This can be used to determine whether the node failure is a diagonal failure,a failure on the same side,or a single point failure.Based on the results of numerical calculations,a strategy for optimal sensor placement in the safety monitoring of railway steel structure overhead systems is proposed.For every three beams,one sensor must be arranged diagonally.(3)Carried out the actual engineering safety monitoring of the steel structure overhead system,using STS-WIFI equipment to verify the reliability of the new vibrating wire dynamic strain monitoring equipment,and long-term monitoring verified the effectiveness of the safety monitoring method of the railway steel structure overhead system.