Lateral Anti-overturning Stability Analysis And Reinforcement Research Of Single-column Pier Ramp Bridge Based On Large Rotation Of Elasticity

With the rapid increase in traffic flow in and between cities in my country,urban elevated,overpasses,and highway overpasses have been widely used in the past 30 years.Since most of these bridges are built at densely intersecting traffic networks,the land There are high requirements for space utilization.The single-pillar pier continuous box girder bridge is widely used in the construction of this type of bridge because of its beautiful appearance and small footprint.In the past 10 years,the single-pillar pier continuous box girder bridge overturning and falling beam accidents caused by overloaded vehicles have occurred frequently,causing huge losses of people’s property and bad social impact.Explore the single-pillar pier continuous box girder bridge overturning mechanism and overturning influencing factors And anti-overturning reinforcement measures have direct guiding significance for the design,reinforcement and safe operation of bridge structures,and have great social significance for building a harmonious society.In the context of the release of local documents in many places to carry out the safety investigation and treatment of single-pillar pier bridges,this article is based on the investigation of bridge overturning accident cases and existing research results,based on the elastic large rotation geometric nonlinearity and contact nonlinearity theory Through the establishment of a box girder-support-pier interaction model,numerical analysis is used to study the overturning mechanism and overturning influencing factors of a single-pillar pier continuous bridge bridge,and a bridge in Hai’an,Zhejiang Province is used as an engineering background to stabilize it against overturning Comparison of calculation and reinforcement schemes,the main research results and work content are as follows:(1)Considering the elasticity of the bridge structure,the nonlinearity of geometric large rotation and the nonlinearity of the contact between the support and the beam body,a linear and curved single-pillar pier continuous box girder-support-pier interaction model is established.(2)Taking Chunhui Bridge as an example of overturning,study its critical overturning load in the state of rigid body and elastic body,and explore the change law of support deformation,support reaction force distribution,overturning axis and beam overturning angle with overturning load,Reveals that under eccentric load and overload,the deformation of the support and the beam body will change the reaction force of the support and cause the offset of the resultant reaction force of the support and the position of the overturning axis,thereby accelerating and intensifying the increase of overturning moment.The degree of vacancy of the support and the friction between the beam and the support cause the beam to slide down after the friction exceeds the limit.(3)By analyzing the anti-overturning stability coefficients of linear beam bridges and curved beam bridges under the action of lane load and vehicle load,and comparing the advantages and disadvantages of the new and old codes,the results show that the calculation of the stability coefficients in the code is more concise and applicable to any bridge type.(4)The overturning stability analysis is carried out with the radius of curvature,support spacing,support size,and side-to-span ratio as the factors affecting the overturning stability,and the curve box under the load of the highway-Class I lane and the 55 t vehicle load are respectively discussed.The anti-overturning ability of the beam bridge.The results show that the stability coefficient decreases with the increase of the radius of curvature,the distance between the supports increases,the size of the supports increases,and the side-to-span ratio increases.(5)Based on a certain bridge,the four options of adding steel cap beams,adding tie rods at joint ends,adding auxiliary piers and widening pier columns were used to analyze the anti-overturning reinforcement,and the structural size of the reinforcement model was optimized.analysis.Among the four reinforcement schemes,the effect of adding a cap beam,adding auxiliary piers and widening pier columns to single-pillar piers is the same.The specific use depends on the bridge type.The addition of tie rods at the joint ends can effectively prevent the support from being emptied,but under heavy load conditions.The effect is drastically reduced.