LAUSR

Abstract Steel-reinforced rubber isolation bearing has been widely adopted in ground structures to improve structural seismic resistance property. However its use in underground structures is not elaborately examined. Through a series of shaking table tests, the functionality of isolation bearings connected to structural intermediate columns' feet in underground structure during seismic actions is investigated, compared with the dynamic response characteristics of model structure with general reinforced concrete columns. Result analysis shows that dynamic reaction of underground structure is fundamentally determined by soil motions, the isolation bearing can not shift structural fundamental period away from the prominent frequency of seismic waves to enhance structural seismic resistance capacity like the way in the case of ground structures. However, as the soil-structure interaction changes a lot along structure height, isolation bearings can effectively obstruct lateral shear forces developed in top structural part from transferring into down structural part, which will avoid force concentration in low structural part, making structural deformation distributed uniformly along structure height in comparison with the deformation in structure without isolation device. Other changes of underground structural dynamic reactions to earthquakes brought out by isolation device will be also detailed.