Research On Influencing Factors Of Anti-overturning Capability Of Single-pillar Pier Continuous Girder Bridge

In this paper,based on the theory of bridge stability and finite element method,the paper analyzes the factors influencing the overturning resistance of single column pier continuous beam bridge.According to the analysis results,the technical measures to improve the overturning performance of existing bridges and new bridges and the management strategies of the bridge operation stage are put forward.The main contents and achievements of this paper are as follows:1.By summarizing the literature and research status of bridge overturning at home and abroad,the research contents and methods of this paper are clear.MIDAS-CIVIL is used to analyze the anti overturning performance of 218 bridges.Based on the analysis results,the simplified checking method and the most unfavorable design parameters of single column pier continuous beam bridges are summarized,which lays a foundation for the research on the influencing factors of bridge anti overturning.2.The control variable method is adopted to analyze the influence of curvature radius,support mode,span number and span combination mode,width,temperature and overload on the overturning performance of single column pier continuous beam bridge.The results show:●The influence of radius on anti overturning performance is as follows: Negative reaction force appears on the supports at both ends of the bridge with radius of curvature less than100 m,which does not meet the requirements of characteristic state 1;the bridge with radius of curvature greater than 300 m does not meet the requirements of anti overturning coefficient of characteristic state 2;the bridge with radius of curvature about 200 m is in critical overturning state.●The influence of supporting methods on anti overturning performance is as follows: Increasing the distance between end supports improves the anti-overturning ability of small radius bridges significantly better than that of large-radius bridges;the effect of intermediate support on overturning resistance is the best for double support,the second for pier beam consolidation,and the worst for single support.●The influence of span number and span combination on anti overturning performance is as follows: When each span is the same,the anti-overturning ability of the span number from one-span to five-span bridge first decreases and then rises,and it is the lowest at three-span.When the total span is the same,the two-span and four-span bridge have greater anti-overturning capacity,and the three-span bridge has smaller anti-overturning capacity.The larger the mid span is,the lower the anti-overturning ability is.●The influence of bridge width on overturning performance is as follows: The anti overturning ability is negatively correlated with width.●The influence of temperature gradient on overturning performance is as follows: The temperature gradient(positive temperature difference)has a great influence on the anti overturning performance of the bridge,while the overall rise and drop of temperature have little influence.● The influence of overload on overturning performance is as follows: The anti overturning ability is negatively correlated with the moving load.3.The measures to improve the anti overturning performance of the bridge are put forward.The existing bridges can take measures to increase the bearing spacing or uplift restraint;The new bridge adopts the measures of adjusting the support position,changing the middle support mode and changing the upper structure design;The operation management should strengthen the supervision of overload.