Supertall building is featured by the huge construction cost and difficulty, so the most efficient location and a minimum number of outrigger trusses are key design issues. Because the deformation shape of high-rise building presents bending characteristics, compared with other energy dissipation schemes, a viscous damped outrigger can reduce the wind-induced acceleration with less viscous dampers while still yielding a high vibration reduction efficiency. The vibration reduction schemes used to control the wind vibration include tuned damping schemes with a tuned mass damper (TMD) and energy dissipation schemes with viscous dampers. There are two methods to solve the problem of the wind-induced vibration comfort of structures, namely, adjusting the dynamic characteristics of the structure or adopting energy dissipation and vibration reduction schemes.
#WEBWALL BENT STIFFNESS SEISMIC CODE#
This type of structure system is often accompanied by damped outriggers because as the height increases, the wind-induced horizontal vibration acceleration at the top of the structure is more likely to exceed the code provisions this is the wind-induced human comfort problem of tall buildings. The prevalent structure system adopted in supertall (>300 m) and megatall (>600 m) buildings is the mega-frame core wall structure system, where the mega-frame is characterized by a secondary system. Thus, applying this optimal design method in combination with the simplified model can save significant analysis and design time and is conducive to the application of viscous damped outriggers in practical engineering. The accuracy and effectiveness of the simplified model and the optimal design method proposed in this study are illustrated. A 600-m supertall building is presented as a case study. An optimal design method combined with the simplified model, which aims to minimize the damped outrigger system cost, is proposed. Parametric analysis shows that the simplified model has high acceleration prediction accuracy. This simplified model is a plane model that includes both core walls and frames whose member size can be extracted from the original structure.
In this study, a simplified wind-induced vibration prediction model is proposed based on the mechanical characteristics of megastructures. Additionally, the conventional simplified model composed of one cantilever beam cannot be used for the analysis and design of a viscous damped outrigger. However, time history analysis of the prototype model considering the nonlinear characteristics of viscous dampers is time-consuming, which is not conducive for iterative design optimization. Because the deformation of a supertall building usually presents bending characteristics, a viscous damped outrigger can reduce the wind-induced vibration of a supertall building with the installation of a small number of viscous dampers. Megatall and supertall buildings often adopt megastructure systems characterized by secondary structure systems, and the serviceability problem caused by wind-induced vibrations often becomes the dominant factor in the structural design.
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