The Research On Thermal Action Of Box Section Of Long-Span Continuous Rigid Frame Bridge

Bridge structure, in a constantly changing natural environment conditions, will be affected by the surrounding environment inevitably. The influence of the environment mainly reflects in:The sun sunshine radiation, the surrounding temperature changes, etc. Because concrete is poor in transferring heat, bridge structure will produce non-uniform temperature field under the effect of solar radiation. The ever-changing temperature field will produce temperature stress in concrete structure, especially the statically indeterminate structure system, and it will form potential threat on the durability of bridge structure.It is of great significance in theory and practice to reveal the regularities of temperature distribution in concrete structure, because the temperature stress due to ever-changing field is sometimes even greater than other stress due to other load. The observation data show that different geographic environment and atmospheric environment conditions have great influence on the temperature stress of bridge structure. The temperature distribution of different climate conditions and region in concrete structure has different characteristics. Temperature load will exert more obvious influence on the state stress and displacement of bridge structure, especially in region of great temperature difference.There is a big difference of temperature between morning and night in Henan Linzhou located in TaiHang Mountain due to its strong sunlight, and the special kind of climate condition is of great significance in the research of temperature field distribution of the bridge structure.This paper do some observation of the temperature distribution on the bridge structure of box girder,which located in Henan and its name is the dew bridge, and then using ANSYS to establish model to simulate the temperature distribution in the box girder section, establish the pattern of the distribution of temperature gradient which conforms to TaiHang Mountain. This observation has great important theoretical significance and engineering practical value.This paper makes a three-dimensional entity model of the dew river bridge while it is at the stage of cantilever construction by ANSYS to calculate the influence of the temperature stress on the vertical displacement and longitudinal stress when the construction is still on. Finally, it makes a three-dimensional beam element model of the dew river bridge through the MIDAS/CIVIL to calculate the influence of temperature load on the vertical displacement and longitudinal stress when the construction is done. It concludes that the temperature effect should not be ignored, and it should consider the influence of temperature load during the design of bridge structure.