Research On Optimization Design And Applicability Of New Large Longitudinal Rib Orthotropic Steel-Concrete Composite Bridge Deck

In order to enhance its fatigue resistant performance,large longitudinal rib orthotropic steel bridge deck was proposed by domestic and overseas scholars.Preliminary study showed that:large longitudinal rib orthotropic steel bridge deck possesses outstanding advantages in the field of anti-fatigue capability of the whole structure and high economical efficiency compared with conventional orthotropic steel bridge decks. However,there exists some tough issues that its fatigue strength was insufficient in rib-to-deck welded joints and local region of rib and web.Further improving the structure design and enhancing fatigue properties of the above control sites is the key to promote the application of large longitudinal rib orthotropic steel bridge deck.Arranging concrete structure layer on the large longitudinal rib orthotropic steel bridge deck to form new large longitudinal rib orthotropic steel-concrete composite bridge deck was an effective approach to improve the fatigue performance of predominant types of vulnerable fatigue details of large longitudinal rib orthotropic steel bridge deck.And optimization design and the applicability in typical bridge types of new structure were conducted.The main work was as follows:(1)The development course of orthotropic steel bridge decks and two typical problems of conventional orthotropic steel bridge decks was summarized.And large longitudinal rib orthotropic steel bridge deck was introduced and its advantages and disadvantages were pointed out.On the base of that,the development of new large longitudinal rib orthotropic steel-concrete composite bridge deck was briefly discussed.(2)Finite element model was established based on typical large longitudinal rib orthotropic steel-concrete composite bridge deck to analyze the effectiveness of adding concrete layer in improving the stress and strain distribution and increasing local stiffness of large longitudinal rib orthotropic steel bridge deck. The composite bridge deck could greatly increase the stiffness of the bridge deck,decrease the stress of predominant types of vulnerable fatigue details.(3)The sensitivity of main design parameters which influence the load-bearing of new large longitudinal rib orthotropic steel-concrete composite bridge deck was analyzed.On the base of that, optimization design of new large longitudinal rib orthotropic steel-concrete composite bridge deck was conducted using Kriging method. Through the comparison with the same type of bridge built, it was found that the Kriging method was suitable in the optimization design of large longitudinal rib orthotropic steel-concrete composite bridge deck.(4)According to hot spot stress method, take the optimized results into application to investigate the anti-fatigue performance of three kinds of bridge deck.The combined system of orthotropic steel bridge deck with concrete layer could greatly reduce fatigue stress amplitude and improve the fatigue life.(5)Relying on the Hongkong-Zhuhai-Macao bridge deep water area of the non navigable span in standard combined continuous steel box girder bridge to explore the applicability of large longitudinal rib orthotropic steel-concrete composite bridge deck in long span continuous beam bridge.Results showed that large longitudinal rib orthotropic steel-concrete composite bridge deck possessed hig applicability.