Distribution Monitoring Research On Bending Deformation Of Single Cell Box Girder By The Way Of The Distributed Strain Measuring

Too much longitudinal deflection in the midspan of many bridges in China has always been present in our country as one of main problem during the period of the construction and maintenance of one bridge. As a parameter being long-term adopted for monitors, longitudinal deflection has become more and more important in the monitoring of bridge. But the current widespread use of the "point" measurement technology can only get the deformation of very small amount of the Preset points.The existing study of monitoring for the distribution of deformation monitoring is mostly aimed at solid rectangular beam while neglect the special research in the bridges with common sections(eg. box girder cross-section forms).For that reason, With the example of simple box girder, this paper conducts a series of research, the main results are lifted as follows:(1) research on Computational theory based on the strain distribution of box beam deflectionWith reference of the characteristics of box beam, this paper focus on the research of shear lag effect of the flange and transverse shear deformation of the web, which has the larger effect on box girder deflection. Based on elementary beam theory and improved conjugated beam method, the paper puts forward method of deformation monitoring for box girder beam based on the distributed strain.(2) theory of box girder deformation monitoringCombining the finite element software ANSYS and MATLAB, this study fulfills the validation of the theory about the calculation of deformation used in the monitoring of deformation in the girder beam, and puts forward the rational method which is suitable for monitoring of the girder beam based on the strain distribution.(3) Experimental study of box girder deformation monitoring methodIn order to test the proposed monitoring method, a relevant test artifact is made based on a simply supported box girder single room in this paper. And the experiment result shows that the average tolerance is floating within7%, when detectors are at the best setting position.