Dynamic Response And Safety Assessment Of Reinforced Concrete Girder Bridge Under Blast Loading

In recent years,with the rapid development of the highway,the transportation is more and more convenient,and people's travel efficiency is greatly improved.As an important part of the highway,the bridge plays a unique role.In the use of bridge,accidental explosion causes damage to the bridge,such as structural damage and serious collapse accident,resulting in the disruption of traffic lines,which is difficult to restore in a short time.The consequences are inestimable.According to this phenomenon,a finite element numerical analysis model is established by program ANSYS/LS-DYNA in this paper.The dynamic response and safety assessment of reinforced concrete girder bridge under blast loading are studied,including the numerical simulation method,dynamic response and influence parameter analysis,and safety assessment of reinforced concrete girder bridge.(1)Consult many relevant documents and research achievements.The properties of blast wave are analyzed and summarized,including the classification of blast loading,basic parameters,similarity law,decay of pressure history curve and calculation method of blast load.The simulation method of blast loading is determined.(2)Based on the explicit dynamic program ANSYS/LS-DYNA,simulate the dynamic response of reinforced concrete beam under blast loading.In the reinforced concrete model,the common node method is adopted.The concrete adopts 3D-SOLID element and uses the material model J-H-C which can consider the material strain rate and damage.The failure criterion of concrete is defined by the limit strain.The steel bar adopts 3D-BEAM element and the material model Plastic-Kinematic which can consider the strain rate and failure.(3)Based on the numerical simulation method,the dynamic response of reinforced concrete beam simply supported under blast loading is studied.The dynamic response results are analyzed,including displacement,velocity,acceleration,pressure,principal stress and bar axial stress.The effects of the parameters on the dynamic response of the structure are discussed,including the explosive equivalence,proportional distance,compressive strength of concrete and longitudinal position of explosive.(4)Under the blast loading,the local or global damage of bridge may occur.A reasonable safety evaluation criterion is proposed to evaluate the safety of experienced explosion bridges.