Seismic performance of base-isolated AP1000 shield building with consideration of fluid-structure interaction.

• Base-isolated AP1000 shield building with FSI effect is investigated in earthquake. • Optimal water level ratio of the isolated building is suggested. • Method of avoiding the water resonance is proposed for the isolated building. • Dynamic performance of both the isolated and fixed buildings is studied comparatively. Seismically-induced FSI effect on dynamic responses of AP1000 shield building with base isolation is focused in this study using numerical simualtion. The numerical model is firstly validated by comparison with existing experimental results, which is capable of simulating dynamic behaviors of the water partially-filled shield building with seismic isolation using high damping rubber (HDR) bearings. The influences of FSI on seismic performance of the base-isolated and base-fixed AP1000 shield building with various water levels and on the corresponding isolation effectiveness are comparatively explored in details. Results show that base isolation can reduce the fundamental frequency of the shield building and make it close to water sloshing frequency. It is necessary to ensure an reasonable isolation design to keep the fundamental frequency away from the sloshing frequency and then to avoid the water resonance. Seismic isolation can offer a substantial benefit for the earthquake-resistant design of the shield building even filled with different levels of water, because the structural primary resonance is effectively transformed to the sub-resonance by application of base isolation. Dynamic responses of base-isolated models are influenced significantly by FSI and an optimal water level ratio of 0.8 is suggested to achieve excellent seismic performance for such structures. [ABSTRACT FROM AUTHOR]