Application Research On Buckling-Restrained Braces In Longitudinal Seismic Design Of Continuous Beam Bridge

Mass of Continuous Beam Bridge is very large. There is a fixed bearing along longitudinal direction,which bears enormous seismic load.If the techniques of seismic mitigation and isolation is adopted, currently most of the isolation bearings exist some problems. First, their stiffness can not meet the requirements of normal operation of high speed vehicles. Second, the damping control process is too complex and can not meet the engineering needs of the durability and reliability. Third, they have problems of high cost and difficult repairing of post-earthquake.The idea of Support Functional Separation is changing fixed bearing into activities bearing.In normal service condition, supports bear vertical force and beam-end corner, but horizontal force and displacement of beam are beared by energy dissipation device. When the earthquake happens, seismic horizontal force will transfer into pier through e-nergy dissipation device. Buckling-Restrained Braces have plump hysteretic curve and good energy dissipation performance.Therefore, its application in longitudinal direction of continuous beam bridge will be an effective isolation design method.For Bucking-Restrained Braces, this paper esplains the theoretical analysis,includ-ing thestructure and the force performance, work principle and design method. Then re-quirements to the stiffness and damping design principles of Buckling-RestrainedBraces are analysised, which make the braces not only have enough stiffness assure vehicles s-mooth operation, but also have enough deformability reduce seismic force.Through the finite element software MIDAS,under three kinds of earthquake wave, the solid models of three Continuous Beam Bridge in different span beam and different height pier are built.The seismic responses of Continuous Beam Bridge with Braces and without Braces are compared, including static mode of first ten modes, bottom moment and shear of fixed pier, axial force of beam,top displacement of pier and longitudinal di-splacement of beam.In addition, braces damping effect to Continuous Beam Bridge with different numbers of braces, different height pier and different arrangement pattern of braces are compared. Support a reasonable choice of the number and layout can achieve more satisfactory damping effect.