Mechanical Principle and Properties of a 600 m New Truss Bridge for Four Line Railway

Abstract:

For railway bridges， the increase of span will lead to the decrease of bridge stiffness and the overrun of beam end angle， which limits the development of super long-span high-speed railway bridges. In order to break through this bottleneck， a super long-span new truss bridge is proposed. The structural system has good mechanical properties and its stiffness is much higher than that of the arch bridge， which is especially suitable for railway bridges. In the new system truss bridge， inclined rods with a large stiffness are set at the angle of the truss to effectively restrain the line displacement of the main girder， and double trusses are set in the middle as well as triangular trusses are set on both sides， so that the structure has a better flexural capacity， stiffness， and stability. In addition， the bridge is mainly steel structure， which can be prefabricated and assembled， Therefore the construction is convenient and fast. The structural form and mechanics principle of the new truss bridge are described. By using the finite element software Midas/ Civil， the structure of a 650 m half through span reduction truss bridge is analyzed and studied. The results show that the strength， vertical stiffness， beam end angle， stability， integrity， and dynamic characteristics of the half through span reduction truss bridge satisfy the requirements， and it has better mechanical properties and economy than the traditional arch bridge.

Key words:high speed railway bridge;new truss bridge;finite element;stiffness;beam end angle