Study On Structural Analysis And Construction Monitoring Of Continuous Stell Truss Girder Bridge Considering Temperature

With the rapid development of China’s economy,the bridge construction task has been more arduous than ever,especially the steel truss continuous beam bridge,which occupies a pivotal position in China’s bridge construction.In the natural environment,the structure of the bridge has experienced the change of cold and heat throughout the year.The influence of temperature on the structure of the bridge is widespread,mainly in the two aspects of deformation and stress.The larger the span of the bridge and the more complex the structure,the more obvious the temperature function is,and the temperature effect has become an important factor in the design and construction.In addition,Regardless of highway,railway steel truss beam bridge,the difference between actual linear and internal force and target value will appear in the construction.Therefore,in order to ensure that the steel truss bridge can reach the design line and the allowable internal force,the construction monitoring must be carried out during the erection of the bridge.In this paper,combined with the actual project of the HUOTOUWAN bridge,the theoretical analysis of the temperature and the construction site survey are carried out to ensure the smooth construction of this project.The influence of the MIDAS CIVIL finite element software on the influence of temperature is analyzed.This paper mainly studies the following aspects:(1)Elaborate the concept of temperature effect,the classification of temperature load and the factors affecting the temperature distribution.The analysis of temperature-related problems in steel truss girder bridge engineering shows that it is necessary to pay attention to the influence of temperature effect in the design,construction and operation of the bridge,especially the construction monitoring.(2)According to the temperature data acquired from the construction monitoring of the key bar of the main tunnel of HUOTOUWAN bridge,the temperature distribution of the chord,the lower chord and the belly of the main steel truss is obtained.The extreme low temperature of the truss is-7.7 ℃ while the highest temperature is 68 ℃.The temperature difference of the main truss bar in different weather is analyzed to provide the information on the temperature effect of the steel truss girder bridge in that district.(3)The influence of the whole temperature,local temperature and extreme temperature on the structure of the steel truss girder bridge is studied by using the finite element software MIDAS CIVIL to simulate and analyze the main bridge structure.The local temperature and extreme temperature have a great influence on the structure,and the local stress changes to 40% of the stress of the bar.The overall temperature is less than 1% of the stress of the main truss.Find the most dangerous parts of the internal force for the future bridge construction monitoring and inspection and maintenance to prepare.(4)Based on the actual temperature distribution laws,the sensitivity calculation results of the temperature parameters during the construction stage of the bridge are analyzed,and the construction suggestions such as the joint bridge temperature,the jointing time and the construction method are proposed.To determine the main best closure temperature between 5 ℃ and 10 ℃,guide the bridge closure smoothly.(5)According to the construction monitoring example of the HUOTOUWAN bridge,the difference between the deformation and the internal force of the main truss of each construction section is different from the theoretical value.Through the analysis,find out the most unfavorable construction stage as the research object.Bridge system is completed,the main stress of the main truss is basically the same as the theoretical calculation result,the deviation amount is less than 20%.Considering the large margin of the cross section strength of the bar,both the allowable error range,Is successful.