Sunlight Temperature Field And Temperature Effect Of Flat Steel Box Girder Of Half-through Single-rib Arch Bridge

The flat steel box girder has beautiful appearance,light weight and good wind resistance,and is widely used in large-span bridges.Due to its large span,the shear lag effect of the main beam is significant.At the same time,the stress level generated by the flat steel box girder under the effect of sunshine temperature is even equivalent to the live load effect.Therefore,it is of practical significance to analyze the sunshine temperature effect of flat steel box girder.In this paper,taking the Tianyuan Bridge in Xiamen as the engineering background,based on the measured temperature data and the finite element model,the sunshine temperature field and temperature effect of the flat steel box girder are studied.main tasks as follows:(1)The sunshine temperature field of the bridge was established based on the measured data.The temperature tester was used to monitor and collect the temperature of Tianyuan Bridge for three consecutive months.Focus on the distribution characteristics of the horizontal and vertical temperature differences of the flat steel box girder of the Tianyuan Bridge,and based on this,use the generalized extreme value analysis method to calculate the extreme value distribution functions of the horizontal and vertical day temperature differences of the Tianyuan Bridge,and further calculate Standard temperature difference.By combining the standard values of temperature difference,eight kinds of the most unfavorable lateral temperature difference calculation models were established.(2)Finite element analysis of the effect of sunlight temperature field.This article introduces the requirements of domestic bridge codes on temperature gradient mode and calculation of temperature effects,and summarizes,analyzes and compares them.The ANSYS finite element software was used to establish the finite element model of the Tianyuan Bridge,and the temperature stress,temperature displacement and distribution characteristics of the top web,and bottom plates of the flat steel box girder of the Tianyuan Bridge under different sunlight temperature fields were calculated.And compare it with relevant regulations in China.(3)Analysis of influencing factors of sunshine temperature field.According to the basic principle of heat conduction,the boundary conditions of heat conduction in accordance with the climate environment of Xiamen were established.The finite element software ANSYS was used to establish the instantaneous temperature field of Tianyuan Bridge on August 9,2019,and compared with the measured temperature data,the accuracy of the instantaneous temperature field was verified.Based on the transient temperature field of the Tianyuan Bridge,the influence of climate and environmental factors on the temperature field of sunlight was changed by changing the solar radiation intensity and wind speed;the cross-section size and surface coating were changed to study the influence of structural factors on the temperature field of sunlight.