Study On Mechanical Performance Of J-type Stiffener

The rapid development of welding technology in the last century has directly promoted the application of orthotropic steel bridge decks,especially in the 21 st century.China’s infrastructure construction has ushered in great development.Bridges,as an important structural form in infrastructure construction,have also ushered in the wave of construction.Orthotropic steel bridge decks are widely used during this period.The subsequent stability problems of the steel box girder stiffening plates are becoming more and more prominent,The common method to solve the instability of stiffeners is to add stiffener.Aiming at the stability of stiffeners,this paper proposes a new type of stiffeners: J-shaped stiffeners.On the basis of summarizing the predecessors,a systematic analysis of the stable performance of J-type stiffeners was carried out,and the following work was mainly completed.Firstly,the background and significance of this topic are introduced,and then the research status and development trends of stiffeners at home and abroad are briefly explained.The reasons for the stability problems are briefly described,and then the stability problems are classified;the theoretical formula of the stiffness ratio of the stiffener is introduced in detail and the formula is derived,and the example is used to verify the stiffness ratio formula;Theoretical solution of critical buckling stress of simply-supported four-sided stiffened plates;details the specifications of stiffness ratios of stiffened plates and stiffeners in major countries in the world.The finite element method was used to analyze the elastic buckling characteristics of J-ribbed stiffened plates.The main factors affecting the critical buckling stress of the stiffeners are the thickness of the mother plate,the spacing of the diaphragms,the flexural stiffness ratio of the stiffeners,and the spacing of the stiffeners.The finite element method was used to analyze the stability ultimate bearing capacity of J-ribbed stiffeners.Firstly,the nonlinear problem is elaborated,and then the domestic and foreign regulations on the initial geometric defects are briefly introduced;the residual stress distribution model draws on the research results of Komatsu Dingfu of Japan;the dual non-linearity of the material geometry is considered,and the residual stress and the initial In the case of geometric defects,the stability limit bearing capacity of J-ribbed stiffeners was analyzed,and the influence of the thickness of the mother plate and the spacing of the diaphragm on the stability limit bearing capacity of the J-ribbed stiffeners was investigated.The effect of vehicle load on the stability ultimate bearing capacity of J-ribbed stiffeners is studied.The uniaxial pressure of the rear wheel is used to discuss the influence of the lateral and longitudinal movement of the vehicle load on the stability of the ultimate load capacity of the J-ribbed stiffener.The results show that under the combined effect of the axial pressure and the out-of-plane bending moment,The out-of-plane bending moment provided by the vehicle load improves the stability ultimate bearing capacity of the stiffener,and the stabilizing ultimate bearing capacity is increased by an average of about 2% compared with the axial pressure alone.The number of axle loads of the car load will not have a significant impact on the axial load capacity of the stiffener.Compared with the no-car load,the axial load capacity has decreased by 1%～2%,compared with the single-wheeled vehicle The ultimate bearing capacity under axial load dropped by 3%～4% under load。...