Research On Key Technology Of Seismic Resistance Of Continuous Beam-arch Composite Bridge

Bridges are a very important part of the traffic line,and they are also the most vulnerable part under earthquake.Once they are damaged in the earthquake,it will not only be a major loss of public property,but will also seriously hinder the subsequent earthquake relief and material transportation,causing greater loss of life and property.Therefore,the study of seismic isolation and isolation technology of bridge structures is of great significance.The seismic isolation bearing provides an effective solution for the seismic isolation of the bridge,which can effectively reduce the cost while improving the seismic capacity.Most of the previous studies focused on seismic isolation design of continuous beam bridges or arch bridges.For the new type of composite bridges such as continuous beam arch bridges,there is less research on seismic isolation,which needs further research and analysis.In addition,domestic scholars have studied the mechanical parameters of lead rubber bearings,but most of them only studied the influence of mechanical parameters of a certain size on the seismic response of bridge structures,which may not be universal.In this paper,a plurality of lead rubber bearings are selected to study the influence law of mechanical parameters?Finally,some scholars believe that the PGA/PGV values of seismic waves can represent certain spectral characteristics.On this basis,this paper studies the effects of ground motion parameters such as PGA/PGV values on seismic response and seismic isolation effects of structures,and the following aspects are completed:(1)On the basis of collecting a large amount of data and reading domestic and foreign literatures,it briefly describes the huge losses caused by earthquake disasters to the people,and introduces in detail various forms of damage effects of earthquake disasters on bridges,and summarizes the current mainstream analysis methods of seismic response,various effective seismic isolation measures and their principles.(2)The finite element model of the continuous beam-arch composite bridge is established,and its dynamic characteristics are analyzed.Then the seismic response of the structure under the design earthquake is calculated by the response spectrum method,and the force characteristics under the action of the earthquake are analyzed.After that,the dynamic time history analysis is used to investigate the influence of pile-soil interaction on the internal force and displacement response of the structure.It is found that the structural response may be underestimated and unsafe,by dynamic time-history analysis without considering the interaction of pile-soil.(3)Set the lead rubber bearing to reduce the response of the bridge structure,study the influence of various mechanical parameters of the bearing on the seismic response of the structure,analyze its influence law,and find that the seismic response does not change monotonously with the mechanical parameters.Then select multiple sets of lead rubber bearings of different specifications,briefly analyze and compare the effects of seismic isolation and isolation,and select the bearing specifications suitable for the bridge structure.Finally,based on this,the seismic isolation effect and seismic isolation mechanism of lead rubber bearing are analyzed systematically.(4)Select multiple seismic waves with different PGA/PGV values,change their peak acceleration amplitudes,and study the effects of PGA/PGV values and ground motion intensity changes on structural response and seismic isolation.