Analysis Of Temperature Field And Temperature Effect Of PC Partial Cable Stayed Bridge In Railway

The partial cable-stayed bridge is a kind of high order statically indeterminate structure, which consists of the main girder, the stay cables and the tower. The solar radiation and air temperature variation will induces temperature problems of partial cable-stayed bridge, such as nonlinear temperature distribution in main girder, temperature difference between cable and girder, overall temperature change. Then the bridge will raise thermal stresses and deformations. The thermal stress and the live load stress are almost equal in value. In additional to the complexity characteristic of partial cable-stayed bridge and the different thermal conductivity of materials, the temperature effect problems of partial cable-stayed bridge are more serious. The current paper about the temperature problem of railway partial PC cable-stayed bridge is very few, further research is necessary. Based on the Dongping waterway bridge program, the temperature problems of the PC partial cable-stayed bridge of railway are analyzed. The three problems are the temperature gradient of box beam, temperature variation between cables and beams, system temperature variation.The research on the temperature gradient problems of the box girder were mainly done in the following four points:In order to study the temperature gradient problems of the box girder, the temperature field of box girder were established. The main work is shown as follows:(1) Based on astronomy, astrophysics and heat transfer theory, the boundary conditions arrays of box girder temperature were established. The influence of azimuth Angle, temperature, date and atmospheric transparency to short wave radiation, long-wave radiation and convection heat transfer were considered in the boundary conditions arrays which also named equivalent air temperature arrays.(2) Two-dimensional thermal analysis model which neglect the longitudinal heat conduction was numerically calculated. The cross section temperature distribution of each time was analyzed and the most unfavorable temperature difference was obtained. Then the results were compared with practical codes.(3) The transverse temperature stress and the longitudinal temperature self-stress were calculated by indirect coupling method. The FEM software MIDAS/CIVIL was used for calculation of longitudinal temperature secondary stress. According to the same deformation, the equivalent linear temperature difference curves were obtained.(4) The parametric researches were conducted to investigate the influence of various factors on the temperature distribution, such as solar radiation, air temperature, thermal conductivity change and cantilever plate.The research on temperature variation between cables and beams, system temperature variation are shown as follows:Both the whole bridge model and the largest cantilever construction model were established by FEA software MIDAS/CIVIL. The effects of system temperature variation and temperature variation between cables and beams were calculated.