Feasibility Assessment of an Innovative Isolation Bearing System with Shape Memory Alloys

Abstract

The objective of this work is to investigate the feasibility of a new seismic isolation device concept based on the superelastic effect given by shape memory alloys. Seismic isolation is one of the most effective options for passive protection of structure, which modifies the global response and improves performances, in particular regularizing the structural response, shifting the fundamental period of vibration, and increasing the global energy dissipation. Shape memory alloys (SMAs) are characterized by unique mechanical properties due to a solid-solid transformation between phases of the alloy. They show high strength and strain capacity, high resistance to corrosion and to fatigue. Regarding the stress-strain constitutive law, the nonlinear hysteresis due to the superelastic effect, that for particular range of temperature can be described like a flag shaped relation, avoids residual deformation, provides some hysteretic energy dissipation and limits the maximum transmitted force. An isolation bearing system based on a SMA superelastic effect is intended to provide the nonlinear characteristics of yielding devices, limiting the induced seismic force and providing additional damping characteristics, together with recentering properties to reduce or eliminate the cumulative damage. Flag-shape hysteresis is characterized by much less energy dissipation with respect to other isolation device technology force-displacement relations, therefore its effectiveness has to be investigated. In this work the dynamic response of the proposed innovative SMA isolation devices has been compared with equivalent traditional bearing response through dynamic time history analyses. Results show that force and displacement demands in the two systems are quite similar for medium to high flag-shape dissipation capability range.

Design of isolated buildings with S-FBI system subjected to near-fault earthquakes using NSGA-II algorithm

“…A number of researchers have explored the potential application of superelastic SMAs in a seismic isolation system (Jalali et al 15 ; Ozbulut and Hurlebaus [16][17][18][19] ; Bhuiyan and Alam 20 ; Gur et al 21 ). Attanasi et al 22 conducted an analytical study to investigate the feasibility of isolation systems with SMAs. They found that an isolation system that relies solely on SMAs for energy dissipation provides less favorable seismic performance than isolation system with bilinear force-deformation characteristics.…”

Shaking Table Tests of the Smart Restorable Sliding Base Isolation System (SRSBIS)

“…Recently, recentering friction-based isolation systems have been proposed based on the coupling between Flat Sliding Bearings (FSBs) and auxiliary Shape Memory Alloy (SMA) devices [Song et al, 2006;Cardone et al, 2003Cardone et al, , 2006Casciati et al, 2007;Attanasi et al, 2009].…”

Performance of Isolated Buildings with Superelastic-Friction Base Isolators under High Seismic Hazards

“…A number of researchers have explored the potential application of superelastic SMAs in a seismic isolation system (Jalali et al, 2011;Ozbulut and Hurlebaus, 2010a, 2011a, 2011b, 2012Rahman Bhuiyan, A., and Alam, 2013;Gur et al, 2013) . Attanasi et al (2009) conducted an analytical study to investigate the feasibility of isolation systems with SMAs. They found that an isolation system that relies solely on SMAs for energy dissipation provides less favorable seismic performance than isolation system with bilinear force-deformation characteristics.…”