| The suspension monorail has little disturbance to the urban surface traffic,and its passenger transport capacity is between subway and bus,which can be used as an important supplement to subway and tram.The track beam of this system adopts the open thin-walled steel box girder with low torsional rigidity,which bears complex forces under the action of dead and live load.Firstly,the existing thin-walled curved beam theory is systematically studied and introduced into the calculation of internal force,deformation and cross section stress of curved steel beam under dead and live loads,and the theory is programmed.In the analysis of track beam,this paper makes full use of the theory to discuss the influence of curve parameters on the static response of track beam in detail.Secondly,a detailed structural analysis of a typical 30 m straight and simply supported track beam in the design scheme was carried out.During the analysis,the track beams were divided into structural systems,and the deformation and stress of each structural system were analyzed and calculated.The numerical value and distribution law of the stress and deformation of the second system of the bottom plate under the load of moving vehicles are mainly discussed.The results show that there is a significant local stress effect on the floor under the action of moving vehicle load,and the stress characteristics of the floor under the action of moving vehicle load are different from those of the continuous beam with multi-point elastic support.At the same time,the mid span stiffener provides some elastic supports for the base plate.In the research process,the static and dynamic test of a full-scale 30 m linear track beam is completed,which mainly includes the stress,deformation,natural frequency,mode and dynamic coefficient of the steel beam under the design load condition.Then,the classical elastic thin-walled beam theory and FEM numerical calculation method are used to study the structure behavior of a typical 25 m curve simply supported orbit beam in the design scheme in detail.The results show that the classical thin-walled beam theory is feasible to calculate the vertical deflection,section torsion angle and section normal stress of the structure under the action of dead and live loads.Because the curved beam adopts the open thinwalled box girder with low torsional stiffness,the section torsion problem is prominent under various loads.The normal stress level of the section caused by dead load is generally low,but the normal stress of the section caused by warping cannot be ignored.At the end of the paper,based on the research and understanding of the structural behavior of the track beams in the previous chapters,referring to the ideas provided by the domestic steel structure design codes,a design method suitable for the bending,shear resistance and local stability of the compression flange of the track beam is proposed. |
