Self-Mass Damper at Tokyo Swatch
by Ryota Kidokoro
The Swatch Group's new flagship structure in Tokyo, the Nicolas G. Hayek Center, featured in ArchitectureWeek No. 416, is built with an array of innovative elements, ranging from elevating showrooms and multistory retractable glass exterior walls to moving floors for reducing seismic forces induced in the building.
Utilizing a combination of base-isolation technology and a mass damper scheme, the Self-Mass Damper (SMD) system is the result of a seismic control concept inspired by the pendulum movement of an antique clock.
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Typically, mass-damper-type seismic control systems are integrated into the building by augmenting a significant amount of mass on top of a structure — characteristically detrimental to the overall seismic performance of the building. However, by utilizing the existing mass, the actual floor plates in this case, as a mass damper to counteract the seismic response of the building, the unfavorable addition of mass was avoided.
The SMD system was implemented by disconnecting four of the upper floors (9, 10, 12, and 13) from the main structure through a combination of slider and high-damping rubber bearings placed at the interface. Each combination of bearings was tuned to provide the maximum damping to the overall structure while maintaining an acceptable lateral relative deformation limit in all directions.
To bring about this system from concept to reality, rigorous structural analyses and full-scale device testing was conducted to validate that the SMD system would reduce seismic forces in the structure by up to 37 percent under a large-scale earthquake loading.
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This technical paper was presented by Ryota Kidokoro at the 14th World Conference on Earthquake Engineering in Beijing, China, in October 2008.