Construction Control And Temperature Effects Study Of Prestressed Concrete Box-girder Bridge

In recent years, as technology continues to progress and improvement, using Cradle cantilever casting method to build large-span continuous beam bridge has been very common. In order to ensure that the into linear and internal forces of final bridge consistent with the design requirements, the bridge construction process must be strict construction monitoring and control. A great deal of Researches found that in the effect of sunshine temperature, will result in a different temperature between the top and bottom surface of the box girder, and a downward distortion in the end of the cantilever box girder, it will make adverse effect on determination of formwork erection elevation, and ultimately affect the linear and force of the bridge,therefore, the research of prestressed concrete box girder bridge in temperature field and the temperature difference between the effects of sunshine has important practical significance.In this paper, using the thermal- structural coupling analysis and secondary development capabilities of ANSYS, develop new calculation program modules to achieve the calculation of the temperature effect of sunshine on box girder cantilever deflection, combined with MIDAS / Civil model to achieve construction monitoring considering the effect of the temperature difference between of sunshine, it has great scientific value to fine calculation of actual construction monitoring.In this paper,take Harbin to Qiqihar Railway Passenger Dedicated Line ballasted track(60 + 100 + 60) m prestressed concrete continuous beam bridge as the research object, using the bridge software MIDAS/ CIVIL do a whole process simulation calculations and simulation analysis of its cantilever construction process,and then use the self-development program to calculate the sunshine thermal effects of cantilever,realized the calculation of camber considering the effect of sunshine temperature in real time, making the construction can accurately determine the camber value of a segment at any time.The methods and calculation procedures in this paper to solve the precise calculation of box girder under the effect of sunshine temperature, considering the solar radiation, longwave radiation beam between ministries and with the outside world,the convective heat transfer and heat transfer and other issues, can be accurately calculated temperature field considering the climatic conditions,geographical and direction of bridge, material properties, structure size, shading effects of flange plate on the web and other factors,then using a three-dimensional beam elements to achieve the calculation of sunshine temperature stress and deformation of bridge structure.