Study On Mechanical Properties Of Cable-stayed Bridge Structure With Truss Box Girder

Because static load and dynamic load of railway bridge are very large, the bridge type often chose composite bridge. With the gradual perfection of national railway network, the previously various composite bridge (such as steel-concrete, beam-arch and ect) are more and more used in railway bridge, but it still can not meet the needs of railway bridge construction. So, it has very important significance for application and theory, which the new composite bridge is proposed and analysed in mechanics property.The main research contents are as follows:(1)Based on the original cable-stayed bridge with truss box girder, the truss box girder and rigid rod were improved to form the cable-stayed bridge structure with truss box girder and rigid rod combined with the load characters of railway, which stay cables is prestressed concrete rigid rod, and truss box girder consist of concrete filled steel tubular brace and prestressed concrete flange plate.(2) Comparative analysis on stress and deformation for cable-stayed bridge with truss box girder and rigid rod and cable-stayed bridge with truss box girder and flexile cable under train load, it was found that the first bridge has the virtue of small deformation and low stress in girder. The influence laws are received, of which mechanical behavior of girder by girder constitution parameter and rigid rod section dimension parameter.(3) It analysed influence of style of cable and the web member filling concrete or not filling concrete on the dynamic characteristics of cable-stayed bridge with truss box girder. The result show that vibration performance of cable-stayed bridge with truss box girder and rigid rod is better than cable-stayed bridge with truss box girder and flexile rod, the web member with concrete can improve the dynamic performance of cable-stayed bridge with truss box girder and rigid rod, and the dynamic influence parameters of cable-stayed bridge with truss box girder and rigid rod on the girder and rigid rod is obtained.(4)The comparative study of seismic performance between cable-stayed bridge with truss box girder (rigid rod) and cable-stayed bridge with truss box girder (flexile cable) was done. And it was found that the displacement response of the first bridge is smaller. The seismic effect of the ventral bar concrete of cable-stayed bridge with truss box girder (rigid rod) and cable-stayed bridge was also investigated. It was found that the ventral bar concrete can improve the seismic performance of structures.(5) With the characteristics of rigid rod cable-stayed bridge, taking cable-stayed bridge with single loading plane as the research object, the analytical formula for the lateral elastic stability coefficient of the cable-stayed bridge with rigid rod was derived with the torsional deformation of rigid rod considered for the first time, based on energy principle.The contradistinctive calculation of lateral elastic stability coefficient was made with derivation formulas, finite element method and modified elastic support method onthe same example respectively. Result show that the derivation formulas result agree well finite element method ones and the correctness of derivation formulas was verified.(6) In order tosolve the problems that the influence of rigid rod angle on lateral stability of cable-stayed bridge pylon, the derived analytical formula for the lateral elastic stability coefficient of the cable-stayed bridge with the torsional deformation of rigid rod considered was used, for which analyse influence of rigid rod angle on lateral stability of cable-stayed bridge pylon with three difference type cable plane which were radiation-type, harp-type and sector-type cable plane was investigated, and the influence laws of the angle change of rigid rod with difference type cable plane on lateral stability of cable-stayed bridge pylon and non directional force are obtained.It is found that harp-type planecable-stayed bridge withrigid rod has higher stabilitycoefficientand lower effect of structural parameters. So, it is put forward that suggestion on cable plane of cable-stayed bridge with rigid rod is harp-type cable plane.