Seismic Mitigation Mechanism of FPB Applied in Underground Structure

Abstract

There are significant difference in the dynamic responses between the underground and aboveground structures. Based on the seismic mitigation and isolation concept of aboveground structure and the characteristic of seismic response of underground structure, two seismic mitigation schemes with FPB under the bottom of structure and FPB on the top of central column, are designed in this paper. The influences on the seismic responses of a typical subway station are compared by the dynamic time-history analysis of the soil and underground structure system. The results show that the FPB under the bottom of structure can only reduce the transmission of the soil shear effect under the bottom of the underground structure, and the decrease rate is not obvious. However, the shear force and horizontal deformation of the key vertical support components are greatly reduced when the FPB is installed at the top of central column, which can be considered as an effective seismic mitigation measure for underground structure.