Resistive Overturning Stability Analysis Of A Single Column Continuous Steel Box Girder Bridge

In recent years, domestic bridge structure destruction caused by instability occurs sometimes. The overthrow of bridge is becoming more and more valued. The thesis is based on engineering and the predecessors’ research results. The small radius curve of steel box girder bridge transverse overturning stability problem is studied systematically. The mainly following work is finished:First of all, with reference to the actual engineering bridge structure parameters, the 3 X 30m curve of steel box girder single beam model is built with finite element software Midas Civil. By contrast analysis, parameters are one by one modified (bridge width, bridge height, steel box girder bridge counterweight, the radius of curvature, support spacing, pre-eccentricity of support), multigroup comparison model is set up. The overturning resistance of the concrete structure affected by various parameters change is analyzed. The support reaction force, stability against overturning coefficient and overturning load are combined, to analyze impact on the overturning resistance of the concrete structure when the various parameters change, and overthrow calculation results are concluded, comprehensive evaluation of the impact degree on structure overturning resistance when various factors change. Analysis shows support spacing and the increase of pre-eccentricity of support improve the whole rigidity structure obviously, the width of the bridge and the increase of the radius of curvature can moderatly improve the structure overturning resistance. The four parameters can be summarized as the main influence factors. Ratio of beam bottom width and length of cantilever, the change of bridge height and weight of overturning resistance effect is not obvious, which can be summarized as a secondary factor.Finally, on the basis of actual engineering bridge damage and problems found at present stage, the real bridge model is built. The resistive overturning stability is checked. Results show the single bearing block set in the structure has poor overturning resistance. Replace the original bridge pier bearing for double bearing. Results show the pier bearing becomes double support, the structure of the overturning resistance improves significantly, but under 3 times the city-A level vehicle load condition, the inside edge of pier counteracting force value is too small, insufficient safety reserve. On the basis of the pier in the double support, set up 0.2m bearing eccentric. Results show the modified structure fully satisfies the requirement of overturning resistance.