Study On The Anti-Overtuning Stability Of Continuous Girder Bridge

In the national transportation infrastructure,the continuous beam bridge is widely applied because of its good mechanical performance and mature construction method.According to the radius of curvature,it can be divided into straight beam bridge and curved girder bridge.The mechanical characteristics of curve beam bridge are more complex than those of the straight girder bridge,the bending torsion coupling and prestressing loss is particularly prominent.The current bridge design specifications are focused on the strength(bending,shear,compression)of the bridge,while the anti-overturning stability is not explicitly stipulated.This results the judgement of the bridge anti-overturning stability is whether there is negative reaction or even void.A large number of accidents that the negative reaction or void did not appear before the bridge bearing,but when the vehicles overloaded,the bridge rolled over showing the inherent problems of the bridge anti-overturning stability.In this paper,the mechanism of the overturning failure of continuous beam bridge is analyzed,and the main factors which can easily lead to the overturning of continuous beam bridge are studied.An effective anti-overturning design proposal and an improved method for checking the stability of the anti-overturning stability in the design code and the anti-overturning and reinforcement measures in the service bridge are put forward.The main contents are as follows:(1)The common features of overturning in many accidents bridges are concluded.For example,the form of loading beam,the structural characteristics of the bridge itself and the overturning failure form,and the mechanism analysis and the stability identification process of the overturning failure of the continuous girder bridge.(2)The relevant regulations of the current bridge specifications for overturning stability at home and abroad are introduced,and some problems are presented according to the shortcomings of the specifications,and the improvement measures for checking overturning stability are proposed.(3)Based on 4x30 m real bridge,a set of Midas/Civil models is established according to the parameter control method.The anti-overturning stability,the bearing characteristicsand the void sequence of continuous girder bridge under load,support,curvature radius and bridge width are analyzed.(4)On the basis of the situation of continuous girder bridge likely to overturn,to provide design attention for the design target of "overturning failure before strength failure",and provide reinforcement measures for overturning problems of existing bridges.