Mechanical Characteristics Of Integral Abutment Bridges With Different Substructures

The integral abutment jointless bridge is the structure consolidating the beam and abutment to eliminate expansion joints.The integrity of superstructure and substructure will lead to complex load conditions.This paper proposes the calculation models of the structuresoil interaction,use finite element software to analyze the mechanic performances of integral bridge and with different substructures,and analyzed the jointless bridge with the project,it is found that it is not suitable for the application with more rigid substructure.For this reason,this paper analyzes and studies the constructed integrated bridge abutment.The analysis results can be summarized as follows:(1)By summarizing the existing structure-soil interaction model,this paper put out the numerical calculation model considering the abutment-soil,pile-soil interaction.The finite element model is verified by the long-term field monitoring data in the literature,the results show that the model established in this paper can reasonably simulate the boundary condition of the integral abutment,and the finite element calculation is reliable.(2)By using finite element simulation method proposed in this paper,analyzes the different bottom structure form of integral abutment seamless bridge stress characteristics,the key parameters: the temperature effect,after filling properties and bridge span are analyzed.It is found that the stiffness of the substructure can improve the longitudinal and lateral integrity of the structure.However,the sensitivity of the structure to temperature and the compactness of the backfill increased,the sensitivity of the structure increased with the increase of the span diameter,so the structure should not be too long.(3)The spatial finite element model of the project bridge was established.The mechanical characteristics of main girder and abutment under different load cases were analyzed,and the effects of temperature,backfill compactness and bridge span on the mechanical characteristics were studied.Research result shows that,the top of abutment has larger moment and shear force,and the deformation of abutment is complex.The internal of force and deformation of jointless bridge are sensitive to temperature actions.So suitable load cases should be chosen for different members during design process.When the backfill compactness changes from loose to compact,internal force of the structure changes little.The internal force of bridge increases rapidly with the increase of span.Therefore,it is suggested that the bridge span should be restrict.(4)Statistic analysis on foreign and domestic bridges with integral abutment was conducted.The research found that: when the rigid of substructure are higher,it can through the construction with main girder-abutment point,abutment-pile foundation point,and through the back of abutment,the pile filler to achieve the goal of reducing the stiffness of the substructure.