High-speed Rail Orthotropic Steel Bridge Deck Pilot Study

Orthotropic steel decks are light, good integrated, and easy for manufacture and installation, due to these advantages, they are increasingly used in large span high-speed railway bridges.The research on this paper is sponsored by scientific research and development plan projects of railway department "Research of design technology of special passenger railway-- Research of technology of orthotropic steel bridge deck on special passenger railway bridges" (Contract number 2008G007-B).This paper takes Anqing Railway Yangtze River Bridge which is being designed as background.Through the method of combining model test and finite element analysis, this article systematically studies the mechanical behaviors of the orthotropic steel bridge panels from different structural constructions and styles. The main tasks accomplished are as follows:1.A1:4three-panel model was designed and made.Simulation methods of various loads were studied:the axial force of the cables was simulated by tensioning external prestressing tendons;the vertical force of the cables was simulated by the supporting of the elastic beams; the surface load on the birdge deck was equivalent to be replaced by more concentrated force in the model test.2.The plate-shell element method was used to establish a sophisticated spacial FEA model for the segmental test model by ANSYS.Several working conditions are analysed by finite element method, and the deformation and stress state of the orthotropic integral steel bridge panel was studied.3.The model test accomplished all the working conditions, and the measured deflection and stress under various conditions of the model test agreed well with the finite element analysis.This suggested it was feasible to adopt plate-shell element method to establish the sophisticated FEA model for the orthotropic integral steel bridge panel.4. The stress state in "first system" of the segmental model was studied. The results showed that the cross girders of the orthotropic steel bridge had out-of-plate bending stress, and the bridge deck had obvious shear lag phenomenon under the function of the "first system".5. Every cable provides vertical action to deck system which is similar to elastic supporting. Vertical displacement of deck system under vertical load contains two parts. One part is vertical displacement of anchorage point(cross beam) aroused by the deformation of cables and pylon, while the other is steel deck's vertical displacement relative to anchorage point. The former depends on stiffness of cables and pylon while the latter depends on stiffness of deck system.6. The mechanical properties of the the orthotropic steel bridge deck with and without longerons under the track were comparatively studied.The results showed the longitudinal setting can reduce the displacement and stress of steel deck both in the uniform load and in the partial load.7.This paper comparatively studied how the opening L-shape ribs and the silent U-shape ribs affect the mechanical properties of the orthotropic steel bridge deck.The results showed:the mechanical properties of the orthotropic steel bridge panel under deck load didn't make much difference when the two kinds of ribs had equivalent vertical stiffness, and the U-shape ribs took a slight advantage.The research results in this paper provide basis for orthotropic steel bridge panel design of Anqing railway Yangtze River Bridge,and they also provide references for other similar bridges.