Full-scale Experiment Study On The Stability Bearing Capacity Of Stiffened Plate Of Orthotropic Steel Box Girder

Based on the results of the stability test of the steel box girder scale model for Changhong bridge,the relevant experimental research on the stability bearing capacity of the full-scale stiffened plate is carried out for the main failure place of steel box girder.Main work of this paper includes the following issues:In this paper the stability design criteria,failure modes and commonly used calculation theory of compression stiffened plate of steel box girder of ultimate bearing capacity is adopted,based on which the latest practices in the calculation of bearing capacity of stiffened plate,as well as the application of the relevant provisions of the checking code are analyzed.It indicates that the results calculated using both Chinese and European standards respectively are in good consistence to the test results;less consistent is identified with the American Standard,and the least is found with both the British and Japanese standards.On the basis of the comparison between the different bridges with the same specifications,it is found that the relative stiffness ratio of bearing capacity has a great impact on the calculation results.Better controlling the stiffness of the stiffener can be achieved by using the standard of bearing capacity of stiffened plates.The work in this paper may provide some references for future design of steel box girder.With the Changhong bridge example,a series of stable bearing capacity test of full-scale stiffened plate is designed.The test study on the stability bearing capacity of stiffened plate under two operating conditions is carried out from the angle of whether the stiffener is the main stress structure.Condition 1,the stiffened plate centroid as loading center,plate and rib as a composite section bear the pressure together.Condition 2,the motherboard stiffening plate centroid as loading center,the plate as the main stress components,the rib provides increased stiffness requirements of the role,not as the main stress components The test results show that under different loading conditions,the stiffened plate has completely different failure modes.Under axial compression,the local buckling failure of stiffened plate ends,and under eccentric compression,the stiffened plate presents a trend of arching to the stiffener side.On the basis of the test,the finite element simulation analysis is carried out on the stability bearing capacity of the stiffened plate.The influence of initial geometric imperfection and welding residual stress on the bearing capacity of stiffened plate is analyzed,and the influence of stiffened plate’s bearing position on the bearing capacity is further studied.The analysis results show that the influence of initial geometric imperfections and welding residual stress on stiffened plate stability bearing capacity cannot be ignored,the design must be considered when calculating;stiffened plate subjected to eccentric pressure when the eccentricity is large,the stiffener bearing capacity is low,in practical engineering,in order to improve the bearing capacity of stiffened plate.Reasonable decorate plates,to achieve optimal stress position,give full play to the bearing capacity of plate.