Features of Bridge Damages in Wenchuan Earthquake and Application of Damping Bearing System

摘要

Wenchuan earthquake, occurred in Sichuan province on May 12th, 2008, brought great casualties and property loss to the disaster zone. Bridge damages which appeared in various modes have profound influence on transportation system. In order to reduce dynamic response of bridge in earthquakes which may occur in the future, we researched into the typical bridge damages in Wenchuan earthquake and then take a large railway simply supported bridge as example, to facilitate the research, whose full-bridge model will be reduced to a three-span simple beam model. In this paper, we compare the seismic response reduction effect brought by damping device of the simplified model in two cases: case one consolidates the end of pier, case two considers pile-soil interaction. Further analysis in the effect of damping support in the second case is also carried out. In addition, we introduced a new damping bearing which is called E-beam damping bearing. After the analysis we come to the conclusion: ① E-beam damping bearing can effectively reduce the maximum shear and moment at the end of the pier when the bridge encounters earthquake, especially to the reduction of moment. ② When consider pile-soil interaction the pier end reaction is smaller than that in the case of consolidation at the end of the pier. Consideration of pile-soil interaction is equivalent to the case that foundations change into flexible foundations and will extend the natural period of structure, which would be a favorable factor bridge vibration reduction under earthquake. ③ Because the bridge natural period is extended after adding the damping bearing, the reduction effect of maximum internal force is smaller when consider pile-soil interaction. That is, the effect of damping bearing is not brought into full play under the case of pile-soil interaction. These results can be used as reference in Seismic Design and research of large bridge.