The new staggered story isolated structure is a new type of seismic isolated structure developed from base isolated structure and inter-story isolated structure. In order to explore the seismic response of the new staggered story isolated structure considering the soil-structure interaction (SSI), the model of a new staggered story isolated structure considering SSI effect is established to analyze the nonlinear dynamic time-history response under rare earthquakes, and the comparison between hard soil and soft soil was carried out. Results show that the stiffness of the new staggered story isolated structure reduced, the modal period extended and the seismic response reduced by considering the SSI effect, the softer the site soil, the more obvious those changes are. Meanwhile, the shear force and the damage of the core tube decreases, while the shear force and the damage of the frame increases, the shear force transfers from the core tube to the frame. Additionally, the energy absorption of the seismic isolated bearings at the frame reduced, the energy absorption of the seismic isolated bearings at the core tube increased, the softer the site soil, the more obvious the trend is.

For vertical isolated structures with excessive vertical eccentricity for mass and vertical stiffness, horizontal-vertical-rocking response needs to be better understood for vertical isolated structures located in near-fault areas, where long-period velocity pulse can be produced. In this study, a seismic isolation system including quasizero stiffness (QZS) and vertical damper (VD) is used to control near-fault (NF) vertical earthquakes. The responses of horizontal-vertical-rocking coupling base-isolated structure including quasizero stiffness (QZS) and vertical damper (VD) subjected to NF horizontal and vertical ground motions are investigated. Nonlinear dynamic analyses are conducted to study the effects of essential parameters such as isolation system eccentricity, static equilibrium position, vertical isolation period, and vertical damping ratio on seismic responses of vertical isolated structure. It is found that increasing vertical period and damping ratio causes the vertical isolated structures to behave well in reducing rocking responses of structure. The effect of horizontal-vertical-rocking coupling on vertical seismic isolation efficiency is insignificant. The vertical seismic isolation remains effective as compared to the system supported on rubber bearings. The vertical damping can significantly control the vertical displacement and rocking moment.

The new staggered story isolated system is developed according to the base isolated system and the mid-story isolated system. Non-linear finite element model of an eighteen stories new staggered story isolated structure is established. For a comparative analysis, the models of a base isolated structure, a mid-story isolated structure, and an aseismic structure are also established, and their shock absorption performances and damages are analyzed for comparison. The results indicate that the new staggered story isolated structure has a small seismic response, good shock absorption performance which is feasible for application. Besides, the shock absorption performance of the new staggered story isolated structure is a little worse than the base isolated structure but slightly better than the mid-story isolated structure. The bottom of core tube and the story below the frame isolated story have large acceleration response which needs to be paid more attention in design.

No abstract

A new real‐time hybrid simulation (RTHS) scheme for fluid‐structure interaction to investigate structures subjected to seismic and hydrodynamic forces is proposed. In traditional testing of underwater structures, the conflict between scaled specimen and unscaled water makes only partial similarity laws can be satisfied. In the proposed scheme, the hydrodynamic force is regarded as physical substructure (PS) and the target structure under earthquake is regarded as numerical substructure (NS). In RTHS, the deformation and displacement of NS are calculated and sent to the controller of loading system. Loading system deforms and drives the “skin” that makes the state of “skin” identical to that of NS, and then the hydrodynamic force on structure is measured and fed back to NS by sensors. “Skin” is a shell whose shape is consistent with target structure and sensors are arranged on the “skin” to measure the hydrodynamic force. Due to NS is simulated and PS is experimentally measured, only the similarity laws of hydrodynamic force should be satisfied in experiment, and the conflict of traditional testing can be avoided. For verifying the proposed scheme, five evaluation indexes proposed by a benchmark problem of RTHS and a modified index are used to quantitatively analyze the experimental results. The results indicate that the response of underwater structures under an earthquake can be accurately obtained by proposed RTHS scheme. Moreover, the proposed scheme is not only applicable to still water but also has the potential to be applied to the environment of waves and currents.