The Characteristics Of Temperature Field On High Speed Railway Bridge Structure

Abstract:During the heat exchange process between high speed railway bridges and environment, a nonlinear temperature field would be generated under the effects of sunlight, heat convection and radiation heat transfer. With the development of high-speed rail in China, the influence of temperature mainly displayed in:First, there was an interaction between bridges and tracks, the temperature in this system was very complicated, China’s relative codes about the temperature were too simple, the shielding effect of the track system wasn’t considered; Second, temperature effect became a very important subject that concerned the walkability of long-span steel bridge, but the rules about steel bridge’s temperature loads were faultiness. Therefore, it was necessary to research the temperature effects and temperature modes of ballastless track concrete bridge and long-span steel bridge. No2girder in Shangrao and Hutong highway-railway combined bridge were cited as examples to research. The main content included:1. On the basis of Ansys, thermal boundary conditions of simply supported bridges without laying CRTSⅡ (China railway track system) were simulated in the form of heat flux density. The changing law of inside temperature field over time was analyzed. The result was quite close to field test data, the accuracy of the finite model calculations were confirmed.2. A thermodynamic model about simply supported bridges with CRTSII was established. The temperature effect under the shielding effect of CRTSII was researched. The sunshine temperature distribution rules of CRTSII were investigated.3. Thermal stress distribution laws of CRTSII in the typical times were analyzed. Transverse and vertical temperature modes were carried out. Compared with the vertical temperature mode of codes in different countries, the temperature gradient curve proposed by the thesis was more reasonable.4. Hutong highway-railway combined bridge was cited as the example; a finite element model of long span steel truss bridge with double decks was established. The shielding effect of highway deck was considered. The temperature field was researched and the sunlight temperature mode of long span steel truss bridge was preliminary studied.