Side Span Closing Research Of Continuous Rigid Frame Bridge Based On Measured Temperature Field

The conventional sequence of cantilever pouring construction for continuous rigid frame bridge side span closure is: first complete pouring of all cantilever segments,pouring the side span cast-in-place section at the same time,and then set up a rigid skeleton between the side span cast-in-place section and the cantilever end.Then select the appropriate temperature to lock the rigid skeleton,and finally pour concrete to complete the side span closure.This article uses a new method of integrally pouring the side-span cast-in-situ section and the side-span closing section based on the project when the side span is closed.The new sidespan closing method does not set rigid skeleton,and on the basis of accurate calculation of the cantilever displacement,a more effective and refined control method is adopted,which solves many problems in the conventional closing method,such as passive control,inaccurate control and long construction time.In view of the key issues of the new side span closure method,the main research content and conclusions of this paper are as follows:(1)According to the measured temperature field data,the temperature gradient distribution curve of each part of the main pier and main girder was fitted,and ANSYS software was used to model and calculate the displacement and change rule of the cantilever end at each time in a day.(2)The influence law of main pier offset on the deflection of cantilever end under the action of temperature is analyzed,and the counterweight on both sides of the cantilever end of T structure is calculated in detail,and the main pier offset is adjusted with accurate counterweight and the deflection of the cantilever end of T structure is finely controlled.(3)The effect of main pier deviation on beam end displacement under sunshine temperature and the variation law of beam end displacement after counterweight are analyzed.The concrete control method of longitudinal displacement is proposed and the control effect is calculated by modeling.(4)Establish a finite element analysis model according to the design drawings,and compare the stress and linearity of the main girder and pier at each stage of the two closure methods.Up to now,this paper relies on the project to use the new side span closure method has been completed and opened to traffic for more than a year,the technical indicators are good.