| Sunshine will make the temperature stress of the bridge during construction exceed the live load stress.The nonlinear temperature gradient will even affect the stability of the long-span bridge,endangering the construction safety,and the displacement caused by the temperature effect during the construction may affect the alignment of the bridge.At present,none of the temperature gradient models in the national norms have not considered in detail the influence of the location of the bridge site and the direction of the bridge,etc.,and only given a general model.Although China Railway Regulation considered the influence of geography,direction and so on,the given temperature gradient only gives the most unfavorable situation,and does not give any temperature gradient at any moment.Can better guide the design,but can not guide the construction.Accurately determining the temperature distribution in bridge construction has important theoretical significance and practical value for construction accuracy and safety.In this paper,the effects of sunshine temperature difference in bridge construction are studied in detail by taking the Weihe River Bridge(100 + 192 + 100)m and the Pengjiachong Bridge(72 + 128 + 72)m as the research object.The main contents include:(2)Establish an analysis model to accurately calculate the temperature field that takes into account various factors such as climatic conditions,geographical location and the direction of the bridge at any moment;(3)Propose a method based on(4)field experiments to verify the accuracy of the program;(5)to improve the temperature gradient in the existing bridge specification,put forward a new,new method of temperature stress and deformation calculation of the entire bridge structure;The refined temperature gradient model.The research in this paper can satisfy the precision requirements of temperature deformation calculation in the construction control of long-span bridges which are urgently needed to be solved,and provide a reference for the refinement of the standard temperature field model.Finally,it is feasible to use finite element software ANSYS thermal analysis function to analyze the temperature field of concrete box girder.In actual projects,it is only necessary to calculate the most unfavorable temperature field in the temperature field.The exponential curve can basically simulate the vertical temperature gradient in the entire section,but it needs to be improved near the floor.When calculating the temperature field problem of large-span structural box girder,the three-dimensional temperature field problem can be transformed into a two-dimensional temperature field problem.By using the ANSYS secondary development thermal stress analysis system for concrete bridges,a box girder plane model was built,the temperature field of the box girder was simulated,and the calculated temperature field was applied to the bridge structure model to calculate the deflection accurately.When the cantilever is constructed with a long cantilever,the displacement due to temperature effects cannot be ignored.Of course,the vertical model can be performed at a time when the effect of temperature effect is relatively small,and the lower deflection caused by the temperature effect can be avoided,but the secondary development software based on ANSYS can more accurately calculate the lower deflection due to temperature,so that the construction process is not affected by The time limit can be performed at any time.So you can promote the use of and continue to in-depth study of ANSYS real-time temperature field simulation. |
PDF Full Text Request