Seismic Response Analyses of Piled Raft with Grid-form DMWs Using 3D Nonlinear FE Model under Large Earthquake Loads

摘要

To evaluate seismic performance of a piled raft foundation with grid-form DMWs subjected to large earthquake loads, seismic response analyses are conducted in this study. The 3D nonlinear FE SSI model that was well calibrated to the records of the 2011 off the Pacific Coast of Tohoku Earthquake is used in the analyses. For the input motion, the artificial earthquake called 'Level 2 earthquake' defined by the Japanese building design code for performance design is used. The case without the DMWs is also conducted for comparison. As a result, partial tensile failure occurred in DMWs, however, the bending moment of the piles is markedly smaller compared to the case without DMWs. And the sectional force of the piles is reduced to an acceptable level. This indicates that the grid-form DMWs are quite effective in reducing the sectional force of piles under large earthquake load, even if the induced stress in the DMWs partially reaches its tensile strength.