Seismic Behavior Analysis Of A New Structure System Based On Multilevel Displacement Restricting And Energy Dissipation Device

With human's increasing understanding of earthquake and structure's seismic response, seismic design thoughts also develop and become perfect. Seismic fortification criterion has developed from a single level one to a multilevel seismic fortification which is widely accepted nowadays. However, seismic mitigation and isolation skills still stay on a single level stage. Therefore, a structure system based on a multilevel displacement restricting and energy dissipation device is introduced in this paper. This system has built many defending lines of energy dissipation and seismic mitigation, which can cause a dual effect of both mitigation and isolation of earthquakes. It also solves the problem of a conventional continuous girder bridge. That is overloading of fixed pier. By compounding combin39 element and combin40 element of general finite element software ANSYS many times and setting proper element parameters, a finite element model of multilevel displacement restricting and energy dissipation device is established. Based on an approach bridge of a cross-sea bridge, a research is performed on the seismic mitigation and energy dissipation ability of the new structure system based on the multilevel displacement restricting and energy dissipation device, compared with a conventional structure model without any anti-seismic design. The results indicate that the new structure system introduced can significantly increase the anti-seismic ability of the structure compared with the conventional structure. It can also dramatically reduce the pier bottom's bending moment and pier top's shear force on the condition that displacement of main girder never increases.According to the design principle of multilevel displacement restricting and energy dissipation device, adjust each of the factors that affect seismic mitigation and study on the influence rule of each factor. It is shown that first-order and second-order stiffness have little effect on longitudinal displacement of main girder and bending moment of pier bottom. But they have strong influence on shear force. Before yielding of the damping device, the shear force has a proportional relation to the stiffness. After yielding, the shear force remains constant. The first-order yield load can influence and decide the magnitude of pier's bending moment and shear force of damping device with a linear proportional relationship. It has an inversely proportional relation to longitudinal displacement of main girder but with low correlation degree. With the increase of second-order yield force's magnitude, displacement of main girder becomes smaller with a gradually slower decline tendency. But the shear force of damping device linearly increases. Bending moment of pier bottom also increases but with a small increment.