Static Analysis Of Large Curvature Straddle Monorail Steel-Concrete Composite Track Beam

Steel-composite beam is a common type of track beam in straddle monorail transportation.In order to adapt to the urban road traffic layout,straddle-type monorail bridge needs to set curved beam.Straddle-type monorail steel-hybrid track beam has centrifugal force on the curve section,so it needs to set high to offset part or all of the influence of centrifugal force.However,the simulation of curve superelevation is complex,and most of the previous studies did not consider the influence of superelevation,so it is difficult to accurately reflect the static performance of straddle monorail steel-hybrid track beam.In this paper,a strap-type monorail steel-hybrid track girder model considering superelevation is established to analyze the influence of train speed increase on the static performance of the track girder,discuss the speed limit standard of trains under different curvature radii,and compare the influence of different superelevation rates on the static calculation of the track girder.The main work contents are as follows:(1)The finite element model of straddle-type monorail steel-hybrid rail curved beam with a superelevation ratio of 12%was established in MIDAS.(2)Static calculation and checking of track beam.The loads in the model are explained in detail.Calculate the deformation and stress of the rail beam under the action of load combination,and check the deformation and stress according to the requirements of the code,check the result is that the deformation and stress are in line with the requirements of the design code,the structure is safe.(3)The influence law of the train speed on the deformation and stress of the beam and the reaction force of the support is studied,and the reasonable running speed is determined.The results show that:With the increase of the speed,the vertical displacement,stress and support reaction force of each section of the track beam monotonically decrease,while the transverse deformation monotonically increases.When the speed exceeds a certain value,the track beam with small curvature radius has negative support reaction force and the transverse deformation does not meet the requirements of the specification,indicating that the speed limit of the track beam with small curvature radius is needed.Rail beam with curvature radius of 70m shall have speed limit of 40km/h,and rail beam with curvature radius of 100m shall have speed limit of 80km/h.The speed is slightly higher than the speed limit value in the specification,which can be used as a reference for engineering design and speed increase(4)Establish the model of the track beam with different curvature radius and different ultra-high rate,and explore the influence of curvature radius and ultra-high rate on the static calculation results of the track beam.The results show that with the decrease of the curvature radius of the track beam,the vertical displacement and stress of each section of the track beam decrease monotonously,while the transverse deformation increases monotonously,and the support is easier to be tensile,and the speed limit value of the train decreases continuously.Under the same load condition,whether to simulate the superelevation has a great influence on the stress of the track beam,and if not,the stress of the track beam will be seriously underestimated,which explains the importance of the simulation of the superelevation in MIDAS modeling.