Research On The Mechanical Properties Of The Sunflower Arch Bridge And Node Model Test

Sunflower Arch Bridge is a bridge with elegant design, and novel structure. Its spandrel arch connects with the main arch, replacing the stanchion of traditional Open-Spandrel Arch Bridge. It is named after the blooming sunflower-looking. The Sunflower Arch Bridge differs from the traditional Reinforced Concrete Bridge in the force-transmission pattern, due to its innovated structure and complicated stress system. Therefore, it is significant to conduct further research on the mechanical properties of this kind of bridge. Based on the FEM numerical analysis and model testing, this thesis presents an in-depth research on the mechanical properties and the local stress of the junction, and the following researches of this thesis have been achieved.(1) Taking “ the Second Phoenix Bridge” as a research background, the FEM numerical calculation software of Midas/Civil and Ansys is used to analyze the structure system and the mechanical properties of the Sunflower Arch Bridge. Besides, under the influence of different rise-span ratios, various connecting methods and sectional height of connecting the main arch and the spandrel arch, analysis is made to compare the stress properties. It is shown from the statistics that the rise-span ratio of the bridge should be larger than 1/6. Moreover, the “partially- hinging — —consolidation” method can effectively decreases the negative bending moment in the skewback area, narrows the cracking width of the arch ring, and strengthens the ability of anti-cracking and stress resistance. Also, it is a feasible method of adjusting the stress.(2) With testing points that consist of steel strain, concrete strain, and vertical deformation being set in the crucial places such as the junction of the main arch and the spandrel arch, the 1:5 node model of the Sunflower Arch Bridge is firstly designed and built. By adopting jack-lifting, all the static-loading experiments under different loading conditions is finished, while deformation values of various working situations and strain values of each control section have been yield. Meanwhile, comparative analysis of the testing result and the FEM theoretical value proves the reasonableness of the experiment and the precision of the FEM calculation.(3) According to similar theory, figures of stress and displacement of the prototype can be reached by inverse calculation of the results that derived from the model testing. Conclusion can be drawn by comparatively analyze the results of the FEM calculation and the statistics of the prototype of the bridge. That is: influenced by the worst interaction between permanent loading and live loading, the model bridge has excellent mechanical properties, fabulous rigidity, and enough safety reserve. In addition, not only the junction of the main arch and the pier, but also the dome of the spandrel arch embraces proper and safe structure, as well as satisfactory properties of deformation and stress, which further proves the reasonableness and safety of Sunflower Arch Bridge.