Research On The Stability Of Compression Stiffened Plates Of Orthotropic Steel Box Girder

Since the 21st century, with the rapid development of long span bridge, the rthotropic Steel Box Girder was widely used. Under the commission of National Natural Science Foundation of China (50608005), combining China's application experiences of rthotropic Steel Box Girder and on the basis of previous research and design code of some countries, the dissertation presented systematical study of stiffened compression plates mechanical behavior in of rthotropic steel box girder through theoretical calculation and finite element analysis. The main works involved in this research are as follows.Firstly,the history and the state-of-the-art in bridge engineering are introduced, secondly the theorical solution of critical buckling stress of plate and stiffened plate simply supported along its four edges is analyzed, as well as the stability query of arrangments and calculations of these codes is introduced.Through the comparison of the existent methods (finite element method, Timoshenko method and Ichiro Konishi method) with the method proposed by this dissertation, the parameter analysis for the critical buckling stress of the simple-supported stiffened rectangular plate with one couple edges under uniform compression were performed. The important factors in the parameter analysis include the width-height ratio of the parent plate and the flexural stiffness ratio of the stiffener to the parent plate was carried out.The codes regarding the initial imperfections and residual stress from different countries have been compared. In this dissertation, the ultimate bearing capacity for the general thickness plates, open stiffened plates and closed trapezoidal stiffened plates of typical steel box girder were studied, taking account of the geometrical and material non-linearility, initial imperfections and residual stress. After that, the important factors in the parameter analysis include the thickness of the parent plate, Stiffness of stiffener and the geometrical imperfections on the ultimate bearing capacity was carried out.Finally, the impact of the elastic modulus and thickness of deck surfacing and vehicle load on the closed trapezoidal stiffened plates buckling performance were studied.