| In order to reduce environmental pollution and alleviate the travel pressure of urban population,straddle-type monorail,as a kind of urban rail transit,has attracted widespread attention due to its advantages such as small footprint,strong ability to adapt to terrain and landform,and low noise environmental pollution.Traditional box-section straddle monorail steel-concrete composite track beams with a beam width of 850 mm mostly have problems such as self-heaviness and insufficient bearing capacity.In order to solve the above problems,this thesis proposes a beam width It is a 1250 mm pre-bent corrugated steel web steel box-concrete composite track beam,and the research is carried out from the perspective of mechanical properties and section parameter analysis.The main research contents and results are as follows:(1)Preliminary selection and design of the pre-bent corrugated steel web steel boxconcrete composite track beam with a beam width of 1250 mm,the establishment of a numerical model,the calculation of the vertical natural frequency of the numerical experiment beam by the finite element software and the theoretical calculation results By comparison,the feasibility of the proposed track beam selection and the reliability of the modeling technology are verified.(2)Carry out flexural bearing capacity experiments and bridge static load experiments on pre-bent corrugated steel web steel box-concrete composite track beams by using numerical simulation methods to study the failure form and mechanism of the structure under the ultimate bearing state,and evaluate the track beams under different conditions.Performance under load combinations.The results show that the track beam has a strong bending bearing capacity and a large safety reserve;the strength and stiffness of the track beam can meet the structural design requirements under the most unfavorable load combination.(3)Establish a dynamic finite element model of a pre-bent corrugated steel web steel box-concrete composite track girder bridge,analyze the dynamic characteristics of the bridge,and calculate the longitudinal and longitudinal directions of the bridge under response spectrum analysis and nonlinear time history analysis.The seismic response in the transverse direction of the bridge is used to study the internal force and displacement change law of the main control section of the bridge during the whole earthquake process.The results show that the piers of the steel-concrete composite girder bridge always maintain an elastic state during the seismic response process,and no yield phenomenon occurs,indicating that the bridge has good seismic performance and reflects the advantages of the steel-concrete composite structure in terms of seismic performance.(4)When the span of the track beam and the main section size are determined,analyze the bending performance and the most unfavorable load condition of the track beam,and study the influence of the material strength and the thickness of the steel box girder plate on the ultimate bearing capacity of the track beam and the applicable sexual influence.The results show that the strength grade of concrete above C50 and the thickness of the steel floor of the steel box girder are the key parameters affecting the ultimate bearing capacity of the steel-concrete composite track beam;the thickness of the corrugated steel web of the steel box girder mainly controls the maximum shear stress at the support of the steel box girder.The thickness of the steel base plate is the key influencing parameter to control the maximum normal stress at the mid-span,the maximum vertical deflection at the mid-span,and the maximum lateral deflection at the mid-span of the steel box girder. |
