Study On Mechanical Characteristics And Test Model Of Steel-concrete Composite Section Of Hybrid Girde Cable-stayed Bridge

The concrete side span of the hybrid girder cable-stayed bridge has the effect of pressing the weight,balance the force of medium span.The steel-concrete composite section is an important part of the hybrid girder cable-stayed bridge,but its structure is complex,the stress distribution is complex.At present,the application of long-span railway hybrid girder cable-stayed bridges is relatively few,the study on the force characteristics of steel-concrete composite section is relatively few.Tanjiang River Bridge is a bridge example of steel-concrete composite section used in railway cable-stayed bridge,the steel-concrete composite section adopts the form structure of anteroposterior-plate-type.At present,the research on the steel-concrete composite section of the railway cable-stayed bridge is lacking,and the research on anteroposterior-plate-type steel-concrete composite section with cells is also lacking.Based on the above situation,this paper studies the force characteristics of the constituent components of the steel-concrete composite section of the Tanjiang River Bridge,and carries out the scheme design of the test model.The main research contents and conclusions of this thesis are as follows:1.By establishing the finite element model of the steel-concrete composite section of the Tanjiang River Bridge,The stress distribution state of steel box girder exterior panel,stiffness transition section,front and rear bearing plate,steel compartment longitudinal plate,vertical web and concrete structure and so on is studied,under two conditions of maximum positive bending moment of main force + additional force and maximum negative bending moment of main f-orce + additional force,the stress distribution regularity of each constituent components is studied,the stress variation tendency of each constituent components is researched.2.The model test scheme for nteroposterior-plate-type steel-concrete composite section with cells of Tanjiang River Bridge.According to the structural characteristics and force characteristics of the steel-concrete composite section,the test model is designed.Through the comparison and calculation of the two model test schemes,the second test model scheme is selected as the test model of steel-concrete composite section,and the test scheme and loading scheme of the model test are determined.3.Based on the finite element analysis of the test model of the steel-concrete composite section of Tanjiang River Bridge,the stress equivalence of the test model under 1.0 times design load condition compared with the structure of the original bridge is analyzed.The stress distribution state of steel box girder exterior panel,stiffness transition section,front and rear bearing plate,steel compartment longitudinal plate,vertical web and concrete structure and so on is similar to the original bridge structure,the value of stress extraction point is close to the original bridge structure,the stress change trend is similar to the original bridge structure,and has better stress equivalence.