| In recent years,a number of bridge superstructure overturning accidents have occurred in China,resulting in bridge collapse and car destruction.In-depth analysis of these accidents,we can find that the main causes of the accidents are: one is serious overloading and partial loading of vehicles;Third,the industry on the overall overturning of the bridge problem of inadequate understanding.After the overturning accidents of bridge superstructure happened continuously,scholars at home and abroad have carried out active research on the overturning problem of bridge superstructure,and put forward some measures to improve the anti-overturning ability of bridge,the simplified formula for checking the stability of bridge against overturning is also given in the relevant code.However,due to the complexity of the whole bridge overturning problem and the short time of related research,people’s understanding of the bridge overturning problem and the study of the effectiveness of some anti-overturning measures need to be further deepened.In this paper,combined with the actual project,the whole bridge overturning problem is studied by fine numerical simulation.The research work and main conclusions are as follows.2.According to the actual structure of the basin-type rubber bearing,a refined three-dimensional finite element model of the basin-type rubber bearing is established in the analysis of the whole process of the bridge overturning,considering the interaction between the bearing and the pier,the stress of the bearing at different stages during the overturning of the superstructure is obtained,and the position of the weak point of the bearing under the eccentric load is determined.3.In view of the design parameters which may affect the anti-overturning capability of the bridge,such as the bearing spacing,the ratio of side to middle span,the radius of curvature and the height of the bridge pier,the relevant parameters are changed and the three-dimensional solid finite element model of the bridge is adopted,the influence of the parameters on the anti-overturning capability of the bridge is analyzed.The results show that increasing the distance between the end supports and the ratio of the side span to the middle span can improve the anti-overturning ability of the bridge,and the anti-overturning ability of the bridge does not change monotonously with the curvature radius,the curve bridge with the most disadvantageous curvature radius has the weakest anti-overturning ability,and the small curvature radius and the straight box girder bridge have the relatively high anti-overturning ability,the increase of Middle Pier Height will increase the angle of upper structure to some extent,and the influence of Middle Pier Height increases with the decrease of curvature radius.4.In order to improve the anti-overturning ability of the bridge,some designers put forward the consolidation method of the single column Pier in the middle of the bridge and the main girder,the single-column pier with consolidation will be subjected to great bending moment,and may be destroyed,and the deformation of the pier may also affect the anti-overturning ability of the superstructure.In this paper,the problem is studied deeply,the nonlinear material of bridge pier is considered in the calculation,and the damage of pier column in the process of overturning is analyzed.The results show that the pier-beam consolidation method effectively improves the overall anti-overturning ability of the bridge,but under the eccentric load,the strength of the bearing and the pier column becomes the new weak point of the anti-overturning ability of the bridge,when the rotation angle of the upper structure increases gradually under the same load,its anti-overturning ability decreases gradually,but the influence of the deformation of the bridge pier on the rotation angle of the main beam deepens further,the Height of bridge pier has more obvious influence on the anti-overturning ability of bridge. |
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