Temperature Effect Analysis Of Concrete Frame Bridge With Stiff Skeleton Under Solar Radiation

The temperature field of bridge structure varies with the temperature of the environment.The temperature deformation and thermal stress produced by the bridge structure under the effect of temperature distribution are one of the main causes leading to cracks in the operation of concrete arch bridges.Arch bridge is one of the main representative types of spatial structure bridges.The temperature field of Jialing River Bridge has obvious difference along the horizontal and vertical directions and varies with time.In this paper,a three-dimensional finite element model of Arch Bridge Considering Spatial azimuth is established by combining the large general finite element software ANSYS and its powerful APDL programming function.According to the multidisciplinary theory of heat transfer,astronomy and computer graphics,the temperature structure coupled field analysis method is adopted,and many complex factors such as the geometry of the bridge,the location of the bridge,the position of the bridge,the covering effect and other conditions are taken into consideration,and the three-dimensional finite element method is used for the rigid skeleton concrete arch.The environmental temperature effect of the bridge is analyzed.The main contents of this paper are as follows:(1)According to the spatial relationship between the sun and the earth,we determine the parameters of solar elevation angle and azimuth at different dates,different times and different geographical locations.Through the ASHRAE clear space model,the radiation intensity of any earth surface is determined,and the subprogram of the covering algorithm based on APDL is compiled,and the covering algorithm is used to determine whether the surface of the main concrete arch ring is covered by the cover of the bridge surface,in order to determine the heat conduction boundary conditions of the main arch ring at different times.(2)According to the geographical location of the bridge,the parameters of the sun astronomy and the three-dimensional finite element model,the ASHRAE clear space model and the covering algorithm are used to establish the flow framework for calculating the temperature field of the arch bridge's main arch and to compile the parameterized calculation program.At the same time,theinfluence of wind speed,air cleanliness,bridge azimuth and latitude on the temperature field of arch bridge is analyzed.The results show that under the action of solar radiation,the cover effect of the bridge deck on the main arch has a great influence on the temperature field of the main arch.The temperature field of the box section of the arch bridge is not uniform in all directions,and the temperature field of the arch bridge varies with time.(3)According to the calculated most unfavorable temperature difference load of typical cross section,a temperature distribution model suitable for stiffening skeleton concrete arch bridge is put forward,and it is compared with the domestic and foreign norms.According to the calculation results,it provides reference for the maintenance and future works of the Jialing River Bridge in Guangnan road.