STUDY ON EARTHQUAKE DESTRUCTION MODE OF THE LARGEST CANAL CROSSING HIGHWAY BRIDGE BASED ON IEM BOUNDARY IN SOUTH-TO-NORTH WATER DIVERSION

Abstract

  To study the dynamic failure mechanism and damage development law of highway bridge structure under the boundary effect in the process of seismic dynamic duration, the Wenchang Highway Bridge with the largest canal crossing in the South-to-North Water Diversion is taken as an example for seismic design analysis. Based on the finite element and infinite element coupling theory, the infinite element method boundary is introduced, the concrete damage plasticity is introduced, and the half-space free field model is established to study the energy dispersion phenomenon of waves in the boundary and the absorption effect of the infinite element method boundary on wave energy is verified. Under different peak acceleration intensities, the seismic response analysis of the bridge structure was carried out. The results show that: Under the action of selected artificial waves, the damage location of the bridge mainly concentrated in the junction of the box girder supported by the pier, the bottom of the pier and the junction of the pier and beam. The damage tends to develop downward near the bottom of the box girder. The damage at both ends of the beam extends from both ends to the middle. And the bottom and top of the pier have penetrating damage. These are weak points in seismic design. At a horizontal peak acceleration of 0.6g, in addition to damage to the pier column, damage also occurred to the bottom of the box girder. Therefore, when the horizontal peak acceleration of the seismic wave is greater than 0.6g, the failure of the bottom of the box girder is paid attention to. Moreover, the IEM boundary has a good control effect on the far-field energy dissipation of the wave, which is simpler and more efficient than the viscous–spring boundary.