Effects of superstructure response on damage to foundation in liquefied soil

Abstract

Magnitude of damage to structures in liquified soil is affected by various parameters such as input motion, soil density, water table level and contact pressure of structures. This study conducted centrifugal shaking table tests, in which foundations with or without a superstructure were placed on liquefiable soil layer, and investigated the effects of superstructure response on foundation settlement in liquefied soil. The test results show that the overturning moment of structure due to the superstructure response induces an increase in the relative settlement of the foundation. The relative displacement of the foundation is larger with a superstructure than without a superstructure. However, in a case under an input motion with long-time duration, the relative settlement of the foundation without a superstructure becomes almost the same as that with a superstructure. The lengthy input motion causes extensive liquefaction and keeps soil liquefied in a long time. As a result, the soil strength might drop down significantly and the soil could not support the weight of the structure.