The High-speed Railway Prestressed Simply Supported Box Girder Mechanical Properties Of Finite Element Analysis,

The simply supported prestressed box girder is widely used in the high-speed railway construction in China for its excellent static and dynamic performance and short construction period. Qin-Shen, Jing-Hu, Wu-Guang, Ha-Da passenger dedicated railway lines, for example, are a few of those employing double-tracked contents whole-span box girders. The box section girder is in complicated mechanic situation and demonstrates apparent spatial effect, but it is traditionally analyzed in plane state to substitute its complicated spatial mechanical properties, which would lead to error.Yunlianghe bridge, a part of Ha-Da passenger dedicated railway line which applies 32-meter simply supported prestressed box girder, serving as the object of research, the spatial finite element analysis model is built by finite element software ANSYS to analyze its mechanical properties precisely, and suggestions are given on the design and construction of the box girder. The main contents and achievements of the research are presented as follows:1. The result of the bending experiment under static load is analyzed by ANSYS, after which the precision of this finite element model is verified. Due to the limitation of the experiment, it is considered that an overall and real understanding of the box girder properties can be realized through finite element analysis.2. The shear lag effect distribution rule of the girder is revealed from the analysis of its longitudinal normal stress under different loads and of different sections; the influence of eccentric load on the stress distribution is discussed, and then the theoretical calculating method applied to the analysis and design of unbalanced load effect of the box girder in high-speed railway is concluded by comparing calculations of unbalanced load ratio; the influence of bearing irregularity effect on the distribution of girder stress and bearing reaction is analyzed, and the limiting value of bearing irregularity is set.3. The dynamic properties of the girder are evaluated from the analysis of its free vibration, and the relation between the prestress and free vibration is discovered.