Analysis Method Of Temperature Field Of Concrete Box Girder Bridge Based On Shared Weather Data

Bridges have made significant contributions to China's economic construction and social development,but the severe service environment and overload operation have led to serious bridge diseases,huge cost of maintenance and reconstruction and frequent major accidents.Temperature is an important environmental load form of bridges,and it can significantly affect the mechanical properties of bridges.Moreover,temperature is one of the main causes for the damage and performance degradation of bridges,and even causes serious safety accidents.Therefore,the research and engineering application of bridge temperature effect is of great significance for timely detecting and controlling diseases,ensuring safe operation of bridges,improving the durability of bridges and preventing the occurrence of major sudden accidents.However,the current analysis methods of bridge temperature effect rely heavily on the data of field monitoring,thus they cannot meet the engineering analysis demand of most bridges,which greatly limits the ability of temperature analysis and assessment technique to solve engineering problems.Therefore,this paper proposes the analytical method of bridge temperature effect based on meteorological shared data.The basic idea is to adopt the meteorological shared data in large spatial scale,which covers the bridge site,to predict the meteorological condition of the bridge site,and then carry out numerical calculation of the bridge temperature field based on the finite element transient thermal analysis method,so as to obtain the time-varying temperature field,which can reflect the real-time temperature load state of bridges.Meanwhile,the scale model and the actual box girder bridge are used to study and verify the method.The main research contents are as follows:(1)The method of using ground meteorological shared data to forecast the meteorology of bridge site is studied.Firstly,the commonly used interpolation prediction methods and evaluation standards for ground meteorological data are summarized and analyzed;secondly,the content and acquisition methods of the ground meteorological shared data are analyzed;finally,taking into account the geographical location,topography and weather conditions,an optimized analysis is conducted on the main meteorological parameters affecting the temperature effect of bridges,namely,air temperature and wind speed,the optimal prediction method of meteorological parameters and site types are obtained,and the method is verified and analyzed based on the measured data.(2)The calculation and prediction methods of the main and complex radiation parameters that affect the temperature effect of bridges are studied.Firstly,the calculation theories and methods of the main radiation parameters in sunny weather are expounded and analyzed;secondly,the process and attenuation mechanism of the solar radiation from the outer boundary of atmosphere to the ground are analyzed;thirdly,the prediction method of total solar radiation and scattered radiation on the ground based on the meteorological satellite data is put forward.With the statistical analysis of long-term measured big data,two kinds of radiation prediction models are established,and the model is evaluated and verified by using the site monitoring data.(3)Based on the meteorological shared data and the finite element thermal analysis,experimental investigation and engineering verification on the numerical calculation of temperature field of box girder bridges are carried out.In view of the laboratory box girder bridge model on reduced scale and a practical engineering box girder bridge,an ANSYS refined finite element thermal analysis model is established.Besides,the meteorological parameters of the site are predicted by the data shared by surface meteorological stations and meteorological satellites around the site,the corresponding thermal analysis boundary conditions are determined,and the structural temperature field is analyzed by using the method of transient thermal analysis,and a comparative analysis is conducted with the measured data.The results show that the method proposed in this paper has high analysis efficiency and calculation accuracy,thus it is very suitable for the analysis and evaluation of bridge temperature effect without on-site monitoring.