The Mechanical Analysis And Structural Optimization Of The Existing Railway T-beam Whole Span Replacement Special Transport Vehicle

With the rapid growth of railway operation and length under construction in recent years,the damage of railway Bridges caused by various disasters and diseases has become increasingly prominent.Limited technical research on post-disaster repair and restoration of railway Bridges under special conditions such as high pier,deep water and gorge has seriously affected the maintenance and repair work of existing railway Bridges,and the progress of railway emergency support technology has fallen behind the construction and development of railway infrastructure.Therefore,it is very important to study a kind of special transport vehicle for the whole line hole replacement of railway T beam project.It is helpful to improve the construction efficiency of railway bridge replacement engineering and the popularization and application range of online whole hole replacement technology to realize the transportation of whole hole T beam with this special transport vehicle equipment.At present,there is no structural design and related mechanical properties of the special transport vehicle used in the line whole hole replacement of railway T beam engineering,so it is of great significance to carry out the structural design and mechanical properties analysis of the special transport vehicle.In this paper,the SYHJ400/32 all-in-one special transport vehicle for railway bridge transport and replacement designed by the Institute of National Defense Transportation of Shijiazhuang Tiedao University is taken as the research object,and the following research work is carried out in the process of transport,replacement and girder erection involving the special transport vehicle:(1)Based on the original design of SYHJ400/32 all-in-one special transport vehicle for railway bridge,the thesis analyzes the adaptability of the special transport vehicle to the railway construction limit when the straight and curved lines are involved in beam transport,beam replacement and beam erection,and optimizes the center distance of the large frame of the special transport vehicle.Whether the bearing capacity of the existing 32 m,24 m,20 m,16 m span T girder bridge under the load of the special transport vehicle meets the requirements is analyzed,and the center distance of the middle and small bottom frame of the special transport vehicle is optimized.(2)The finite element model of the special transport vehicle is established.The stiffness,strength,mode and stability of the special transport vehicle are analyzed according to the transport and beam working conditions and load combination of different lines,and the dangerous working conditions and unfavorable positions of the special transport vehicle are determined.(3)The mechanical response of the hollowed out position of the large bottom frame,the middle part of the large bottom frame,the connecting shaft of the large bottom frame,the end support cylinder and the middle and low price connection of the special transport vehicle was studied when the whole T-beam of different spans was transported and set up on different lines.The stress of key sections at each position is analyzed and the mechanical response changes of the above structures are summarized.(4)In view of the problems and deficiencies that may occur in the hollow position of the large baseframe,different solutions are proposed,and the section of the hollow position of the large chassis is optimized and designed.The influence of end-of-line support cylinders on special transport vehicles was compared and analyzed,the changes of the supporting force of the end support cylinders under dangerous working conditions were mastered,the mechanical behavior of the connecting shaft of the large base frame and the connection of the middle base frame was analyzed,the stress and buckling stability were analyzed,and the steel plate with higher strength grade was replaced with the connecting shaft.Through the study of this thesis,the structural design of the special transport vehicle is optimized,and the stress and mechanical properties of the bottom frame of the special transport vehicle are mastered,which lays a foundation for the research and development of the new type of special transport vehicle used in the line whole hole replacement of railway T beam project in the future.