Research On Fatigue Design Parameter Of Orthotropic Steel Bridge Deck Based On Response Surface Methodology

Orthotropic steel bridge deck has been widely used in modern large span bridges because of its light quality, high bearing capacity, easy to be assembled, short construction period and other significant advantages. However, fatigue injury of orthotropic steel bridge deck which under the repeated load may easily to produce cracks due to the error of manufacture and installation, initial defects and significant stress concentration. Fatigue of the orthotropic steel bridge deck directly affects the service life of steel bridges and it has become a difficult and hot issue in bridge construction, so it is necessary to study the anti-fatigue properties of orthotropic steel bridge deck. This thesis mainly analyzed structural details and design parameters of orthotropic steel bridge deck, its core work was as follows:(1) The developing process of orthotropic steel bridge deck was reviewed, the fatigue damage problems of orthotropic steel bridge deck were summarized, domestic and overseas development situations were introduced.(2) The basic theory of steel bridge fatigue was expounded. The basic concept of fatigue, three type theory of fatigue accumulated damage, method of fatigue life evaluation and the design method about fatigue of steel bridge were introduced.(3) Experimental study about the fatigue properties of structural details between longitudinal rib and panel and the fatigue properties of structural details for longitudinal ribs through transverse were carried out according to Hong Kong-Zhuhai-Macao bridge case. At the same time, simulation analysis of these structural details were made by using ANSYS finite element software, the fluctuate of weld stress which different penetration rate of the weld between longitudinal rib and panel caused and mechanical characteristics of intersect area for longitudinal ribs through transverse were studied.(4) Experimental samples were designed in a reasonable range of design parameters of orthotropic steel bridge deck by using response surface method. Parametric finite element models of orthotropic steel bridge deck were established according to experimental samples. Response values about stress of several vulnerability details were obtained through the simulation analysis. Response surface models of various fatigue details and quality of the finite element model were calculated by using the least squares principle. Finally, response surface models were optimized and reasonable parameter matching of orthotropic steel bridge deck with better performance about corresponding fatigue details were proposed.