Research On Temperature Field And Temperature Effect Of Box Girder Bridge With Corrugated Steel Webs Under Sunlight

The corrugated steel web box girder bridge is a new type of bridge that uses corrugated steel webs to replace traditional concrete webs,and has been widely used in recent years.The bridge structure is affected by solar radiation and temperature changes,resulting in a temperature gradient between the surface and the inside of the bridge,which can cause the bridge to crack in severe cases,which affects the durability and safety of the bridge.The current researches of domestic and foreign scholars mainly focus on the mechanical properties of corrugated steel web box girder,but there are few researches on temperature field and temperature effect.Therefore,this article focuses on the temperature field and temperature effect of the corrugated steel web box girder bridge under sunshine.The main work and results are as follows:(1)It systematically expounds the current research on bridge temperature field and temperature effect at home and abroad,and introduces the basic theory of bridge temperature gradient and box girder temperature field in national standards.(2)Choose a suitable solar radiation model under sunshine was selected,starting from the differential equation of heat conduction and its definite solution conditions,combined with the empirical formula,the vertical temperature gradient distribution curve was derived,and it was compared with the measured temperature gradient and the temperature simulated by the finite element software The gradient is compared.The results show that the formula deduced in this paper can better fit the measured temperature gradient curve.(3)The temperature field and temperature effect of Qianshan River Bridge were analyzed by the finite element software,and the temperature changes of the typical cross-section were obtained.The temperature of the concrete top slab changes according to an exponential function,the temperature difference between the corrugated steel webs in the vertical direction,and the temperature difference between the upper edge of the concrete floor and the lower edge of the floor changes linearly.The calculated temperature gradient is applied to the model,the vertical displacement of the bridge as a whole,the transverse stress and the longitudinal stress of the section are analyzed,and the temperature effect produced by the temperature gradient in the highway code is compared.The results show that the vertical displacement and the tensile stress of the lower edge of the roof under the calculated temperature gradient are larger than those under the temperature gradient according to the highway code.(4)The influence of the change of the geometrical parameters of the corrugated steel web section on the transverse temperature stress is analyzed.Under the condition of the same paving form and the same span,the three parameters of aspect ratio,roof thickness and corrugated steel web thickness were simulated by finite element method respectively,and their changing laws were obtained,there is a large transverse tensile stress on the lower edge of the top plate;The calculation formulas for the transverse temperature stress of the lower edge of the roof and the three parameters are derived and verified through numerical analysis.