Influence Of Seismic Excitation On Anti-Overturn Performance Of Curved Girder Bridge With Single Column Pier

In virtue of the existence of bending-torsion coupling and the relative simplicity of bridge supporting conditions,the curved girder with single pier is prone to capsize under the action of vehicle eccentricity.China is a country with many earthquakes,when the bridge is subjected to seismic action,the stress state of the structure will change.Under seismic action,the structure will produce tremendous lateral or vertical destructive force due to vibration,and the anti-overturning stability of the bridge will be greatly affected..It is of great significance to study the anti-overturning stability of the bridge under earthquake.In this paper,the factors influencing the anti-overturning stability of curved girder bridge with single pier,the overturning failure form of curved girder bridge,the influence of seismic action on the transverse stability of girder bridge and the calculation method of anti-overturning stability coefficient of bridge under seismic action are studied.The main work and conclusions of this paper are as follows:(1)On the basis of summarizing the theory of anti-overturning stability of bridges,this paper explores the overturning limit state of curved girder Bridges,describes the overturning process of curved girder Bridges with single pier under the partial load of vehicles,and gives different overturning failure forms of curved girder bridges.(2)Considering the different influencing factors,the anti-overturning problem under static force is studied.The results show that with the increase of vehicle load,the inner support of the joint end is hollowed out,the supporting effect is lost,and the structure enters the overturning stage.The anti-overturning stability coefficient of the bridge also decreases with the increase of the vehicle load;the pre-eccentricity of the support is increased.The lateral stability of the single-column curved girder bridge can be effectively improved;as the radius of the curved girder bridge increases,the anti-overturning stability coefficient of the bridge decreases first and then increases.(3)In view of the irregular structure of curved girder bridge,considering the translation and rotation of the superstructure of the bridge under the action of earthquake,the calculation formula of anti-overturning stability coefficient of curved girder bridge with single pier and linear girder bridge under the assumption that the action of earthquake is taken into account is derived.Through the response analysis of the bridge structure,the most unfavorable inputdirection of the bridge is determined,and the most unfavorable input direction of the ground motion is carried out.Through the analysis of the supporting reaction force and its deformation characteristics of the bearing,the anti-overturning stability of the bridge under different combination conditions of seismic action and vehicle off-load is studied.(4)The anti-overturning stability of the bridge under different combination conditions of seismic action and vehicle load is checked by theoretical derivation formula,and the feasibility and rationality of the derivation formula is verified.The results show that the rotation Angle of curved girder bridge with single pier under seismic action is very small,and its adverse effect on the anti-overturning stability coefficient of the bridge can be ignored.Under the action of earthquake,the anti-overturning moment decreases,the overturning moment increases,and the stability of the bridge weakens.(5)Established under the various parameters of single column pier curve girder bridge model,the radius of curvature of the bridge,the bridge deck width and the distance between bearing arrangement and pier,considering higher factors according to the formula,the sensitivities of curve girder resistive overturning stability analysis,comparative static analysis results,the seismic action on the influence degree of the curve girder bridge resistive overturning stability and its change rule.The results show that bridges with poor anti-overturning ability are more likely to overturn under the action of earthquake.The effect of seismic action does not change the rule of stability,and the stability coefficient is consistent with the sensitivity under static conditions.