Seismic performance of the visco-elastically connected core tube-suspended frame structure

High-rise buildings incorporating suspended frame substructures have attracted increasing attention due to their advantageous load-transfer mechanisms and architectural benefits. To enhance the seismic performance of such systems, this study proposes a novel core tube-viscoelastic connection-suspended frame (CVSF) structure, and a feasible configuration for the connection is presented. The proposed connection enables relative drift between the core tube and the suspended frame, facilitating efficient energy dissipation while providing vertical support for floor slabs. Analytical models employing flexural and shear beams to represent the core tube and the perimeter frame, respectively, are developed and examined. Compared with the core tube-rigid connection-suspended frame (CRSF) structure, the inter-story drift of the CVSF structure can be reduced by approximately 35%, while the absolute floor acceleration is reduced by about 30-55%. The enhanced seismic performance of the CVSF structure is primarily due to the pronounced deformation of the flexible connection between the core and the suspended frame, which peaks at the lower stories and dissipates more than 50% of the total input energy. The equivalent stiffness ratio α eq has a limited influence (≤ 5%) on the seismic response of the CVSF structure within the investigated range of 1.03-1.68. The peak inter-story drift and the absolute acceleration are moderately reduced (≈ 10%) when more mass is attributed to the shear subsystem (i.e., the suspended frame). For comparative purposes, the analysis is extended to the core tube-viscoelastic connection-grounded frame (CVGF) structure and the core tube-rigid connection-grounded frame (CRGF) structure. The results show that the suspended systems surpass their grounded counterparts, achieving reductions in displacement and acceleration that are more than 20% larger.