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Proposed Configurations for the Use of Smart Dampers with Bracings in Tall Buildings

DOI: 10.1155/2012/251543

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This paper presents wind-induced response reduction in a very slender building using smart dampers with proposed bracings-lever mechanism system. The building presents a case study of an engineered design that is instructive. The paper shows that shear response and flexural response of tall buildings present two very different cases for vibration suppression. Smart dampers are implemented optimally in the building to reduce its response in the lateral directions for both structural safety and occupant comfort concerns. New bracings-lever mechanism configurations are proposed for the dampers to improve their performance. The study shows how the proposed configurations can enable application to flexural response and scenarios where the interstory drift is not enough for dampers to work effectively. In addition, a decentralized bang-bang controller improved the performance of the smart dampers. 1. Introduction In tall buildings, wind-induced vibrations may cause annoyance to the occupants (especially in the upper floors), impaired function of instruments, or structural damage. Safer and more efficient designs are sought out to balance these issues with the reality of limited resources. Structural control can potentially provide more efficient structures. The purpose of structural control is to absorb and to reflect the energy introduced by dynamic loads. Passive, active, and semiactive types of control strategies have been proposed and implemented in a number of civil structures. Although tuned mass dampers (TMDs) and active tuned mass dampers (ATMDs) are shown to be effective in reducing the response of tall buildings under wind loads [1–5], they are large, heavy, and take up valuable space buildings top. Moreover, they present additional cost to the project. Viscous dampers and semiactive dampers can be used as alternatives to overcome the difficulties associated with the application of TMDs and ATMDs. These devices do not require frequency tuning [6]. It is therefore sometimes possible to damp several modes with one device. Smart damping technology is a type of semiactive control that employs variable dampers (e.g., variable orifice, magnetorheological fluid, and electrorheological fluid dampers). Smart damping technology assumes the positive aspects of both passive and active control devices; it can provide increased performance over passive control without the concerns of energy and stability associated with active control. Due to its low power requirements and fail-safe property, magnetorheological (MR) dampers have been shown to mesh well with

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