Girder Transmission Property Study Of Long Span Railway Steel Truss Cable-Stayed Bridge

Due to the steel girder cable-stayed bridge with good strength and stiffness, this kind bridge has been used wildly in large span railway bridges in recent years.While local vertical and longitudinal force transmission of railway steel truss steel truss girder cable-stayed bridge seems to be rather complicated under load and the overall deformation.a variety of bridge deck structure such as densely covered beams or orthotropic bridge deck was used to reduce the local complex stress distribution and force transmitting.This master’s thesis taking Gui-Guang railway Beijiang steel truss girder cable-stayed bridge as engineering background, the Beijiang Bridge used vertical and horizontal beam system orthotropic surface lines with k-shaped brace, overcoming the complexity of traditional simply supported steel truss bridges and improving the stress state of nodebeam.The vertical and horizontal beam system with k-shaped brace was a new deck system of steel truss girder architecture, read and summarized steel truss girder cable-stayed bridge architecture characteristics and behavior analysis of the relevant literature at home and abroad, and as a basis for research in this Master’s thesis and expanded. The main research contents and conclusions are as follows:(l)Using the Midas finite element method, the k-shaped brace of Beijiang Bridge deck system was calculated and analyzed, reaching the k-shaped brace dominated by the axial force (transmitting horizontal longitudinal force).(2) The DC deck system scheme was put forward at the level of KS deck system scheme, and then analyzing coMParatively two kinds deck-based schemes stress and deformation of the bridge deck structure.The shared deck architecture (bottom chord beams and nodes) in two kinds of deck schemes were calculated and analyzed, the force of KS was less than the DC scheme. The deflection and span ratio of KS scheme was 94% of DC scheme, indicating the overall stiffness of KS scheme is better.The short-wave and shear-wave in section 16 of KS scheme was 94% of DC scheme, the short-wave and shear-wave in section 25 of KS scheme were 88% and 76% of DC scheme, indicating the local stiffness of KS scheme is better (taking short-wave and shear-wave of track deformation as evaluation indexes).(3)Transferring force route of bridge deck systems(KS and DC) was analyzed; then taking after crop permanent load (uniformly distributed load) for example, transferring force ratio bridge deck systems-was coMPared. The difference of transferring force ratio between DC scheme and KS scheme was 4.56-9.52%, meaning the KS scheme improved force of node beams.The transferring force ratio of steel deck section was coMPared in the case of the worst-case live load. The difference of transferring force ratio between DC scheme and KS scheme was 4.92%-8.13%, this result meaning the node beam of DC scheme transmitted more deck load.(4)On the basis of chapter 4, the forms of k-shaped brace, stiffness of k-shaped brace, stiffness of node crossbeam key design parameters which effected the steel truss girder transmission force were analyzed, obtained K T-shaped support was clearly superior to inverted T-shape and crisscross;Under the same steel consumption, the nodebeam was more stronger, more load transfer to the bottom chord by nodebeam.The results of this master’s thesis provide design basis for Beijiang Bridge,and are of reference value to other similar bridges.