%0 Journal Article
%T Hybrid Recentering Energy Dissipative Device for Seismic Protection
%A Wenke Tang
%A Eric M. Lui
%J Journal of Structures
%D 2014
%R 10.1155/2014/262409
%X A hybrid recentering energy dissipative device that has both recentering and energy dissipation capabilities is proposed and studied in this paper. The proposed hybrid device, referred to as the hybrid shape memory alloy (SMA) recentering viscous fluid (RCVF) energy dissipation device, connects the apex of a chevron brace to an adjoining beam using two sets of SMA wires arranged in series on either side of the brace and a viscous fluid damper arranged in parallel with the SMA wires. The viscous damper is used because being a velocity-dependent device it does not exert any force that counteracts the recentering force from the SMA wires after the vibration of the frame ceases. In the numerical study, the Wilde¡¯s SMA constitutive model is used to model the SMA wires, and the Maxwell model is used to simulate the viscous fluid damper. To demonstrate the viability and effectiveness of the proposed hybrid device, comparative studies are performed on several single-story shear frames and a series of four-story steel frames. The results show that the frames equipped with the hybrid device have noticeably smaller peak top story displacements and residual story drifts when subjected to ground motions at three different intensity levels. 1. Introduction The concept of performance-based seismic design (PBSD) was developed as a result of a series of devastating earthquakes that occurred in the 1990s [1¨C3]. The primary objective of PBSD is to provide guidelines and methods for siting, designing, constructing, and maintaining buildings so they have enough margin of safety to perform in a predictable manner under earthquake excitations. The Building Seismic Safety Council¡¯s (BSSC) National Earthquake Hazards Reduction Program (NEHRP) and the Structural Engineers Association of California¡¯s (SEAOC) Vision 2000 have set design objectives, prescribed design criteria, introduced analytical techniques for performance evaluation, and attempted to define the margin of safety for buildings designed and constructed in accordance with the proposed guidelines [4]. Figure 1 shows the SEAOC prescribed building performance levels for several types of buildings subjected to three different levels of ground motion. For essential buildings and structures (e.g., hospitals, fire stations, and dams) and hazardous facilities (e.g., nuclear power plants) to remain fully functional or operational after a frequent or rare earthquake event, they need to have the capability to dissipate a sufficient amount of seismic energy during an earthquake and remain almost damage-free after the
%U http://www.hindawi.com/journals/jstruc/2014/262409/