Temperature Influence Analysis Of HONGQI Bridge

At present,large-span and lightweight continuous rigid frame bridges are used in many projects.In this kind of concrete structure system,the temperature stress caused by temperature difference becomes the main factor of structural cracking,and more and more engineering accidents also prove the importance of temperature effect.Under this background,the influence analysis and prediction of cantilever construction of thin-walled high piers under temperature load are carried out The posture of the bridge is very important in the process.As an important substructure of long-span rigid frame bridge,thin-walled hollow high pier is very vulnerable to the impact of external environment,such as solar radiation and sudden temperature change.Due to the poor thermal conductivity of concrete materials,the temperature difference between the inside and outside of the pier body is often large,resulting in temperature effect,which eventually leads to the deviation of the perpendicularity of the pier and the linearity of the main beam,if not added in time In order to correct the temperature effect,it is not only difficult to meet the requirements of the design specifications,but also a threat to the safety of the whole bridge.Based on the construction monitoring project of Hongqi bridge,a continuous rigid frame bridge under construction at Kaichun high speed in Guangdong Province,through measuring the temperature change inside the pier shaft,this paper uses Midas software to establish the entity unit model of the pier shaft and the pole system model of the whole bridge,analyzes and calculates the displacement of the pier shaft caused by the temperature effect,and simulates the solar incidence angle in summer and winter through the temperature gradient of the corresponding angle to complete the calculation The deflection and stress of the main girder can be corrected by predicting the linearity of the main girder.The research content of this paper is as follows:1,The temperature sensor is embedded in the main pier of Hongqi bridge,and the temperature data of sunny weather in summer and autumn are obtained and analyzed through a large number of data collection,and two most representative temperature modes are selected as the temperature load applied on the concrete pier for analysis.2,The temperature sensor is embedded in the main pier of Hongqi bridge,and the temperature data in sunny summer and autumn are obtained and analyzed through a large number of data collection.The two most representative temperature modes are selected as the temperature load applied on the concrete pier to analyze and summarize the research results at home and abroad,and learn the basic theory and calculation method of temperature field systematically The mechanism of temperature stress generation,the basic theory of heat conduction and the finite element method of thermal stress are described in detail.The calculation method of boundary condition of concrete structure and the calculation method of each parameter contained in it are described in detail.Explore the temperature boundary condition of thin-walled high pier and combine with the local initial temperature condition to complete the establishment of MADIS solid model.3,Based on the analysis of a large number of historical meteorological data of the bridge site and the calculation of the change of the sun azimuth in different periods of summer and autumn,the angle of the sun azimuth in winter and summer is simulated in the model,and the corresponding theoretical temperature field is calculated by the main pier numerical model.The theoretical value is compared with the actual measurement,and the influence of the solar radiation in different seasons on the elevation of the model is analyzed for the actual project in this area The revision of the elevation of the neutral formwork provides reference.