| dc.description.abstract | In the past extreme earthquake, observed from the damaged bridges, bearing failure, column failure and deck unseating caused a more serious loss. Therefore, it is full of curiosity that how large earthquake will cause a bridge to collapse and how the ultimate state will be. This study is aimed to analyze the ultimate situation of bridges with rigid bearing system and isolated bearing system through numerical analysis.
The Vector Form Intrinsic Finite Element (VFIFE), a new computational method is adopted in this study because the VFIFE has the superior in managing the engineering problems with material nonlinearity, discontinuity, large deformation and arbitrary rigid body motions of deformable bodies. In the past, VFIFE was used Central Different Method to be analysis method, there are numerical disperses when to solve the Rayleigh damping analysis. Implicit time integration method(Newmark-β) is adopted in VFIFE . Incremental formulation of the equation of motion is used to do iteration and to solve the response at next time step (i+1) including the displacement, velocity and acceleration. Furthermore, this calculation is also used to calculate the internal resultant force and the internal damping force exerted by the elements surrounding the particle.
Three types of bridges, a six-span simply-supported bridge, a continuous-span bridge with hinge and roller bearings and a continuous-span bridge with high-damping-rubber isolators, are analyzed. Through numerical simulation of three bridges with or without unseating prevention devices, the ultimate states are demonstrated and compared. The results show that the unseating prevention devices do not increase the safety of the studied bridges as expected and the performance of the continuous bridge with rigid bearings is better than simply-supported bridge the and isolated bridge to prevent unseating of the superstructure.
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