Seismic fragility analyses of steel building frames installed with superelastic shape memory alloy dampers: Comparison with yielding dampers

Abstract

Smart materials such as shape memory alloys have unique material properties that can potentially mitigate earthquake hazards on the built environment. Implementation of shape memory alloy-based devices on building structures should incorporate two key factors: (1) distinct mechanical features of the devices and (2) inherent large uncertainty stemming from material properties, building geometry, and ground motions. This study conducts seismic fragility analyses of steel building frames installed with superelastic shape memory alloy dampers, which enable both factors to be appropriately considered. First, a thermomechanical constitutive model is utilized to capture all essential characteristics of the shape memory alloy damper. Next, a probabilistic seismic analysis framework is developed to obtain the seismic demands of three critical engineering demand parameters (i.e. peak interstory drift ratio, residual drift ratio, and top floor acceleration) of the building when subjected to modeling uncertainty and a large set of realistic ground motion inputs. Nonlinear time history responses and the associated short-time Fourier transform demonstrate the superior control efficiency of the shape memory alloy damper in limiting the building’s residual drift and top floor acceleration. Furthermore, seismic fragilities of the buildings when installed with shape memory alloy dampers are compared with those when equipped with yielding dampers. The study indicates that under different levels of ground motions and various ranges of modeling uncertainty in structural parameters, shape memory alloy damper consistently outperforms the yielding damper in reducing the seismic fragility of the building at both component and system levels.

Strain rate dependent formulation of the latent heat evolution of superelastic shape memory alloy wires incorporated in multistory frame structures

“…However, modern models have been so far quite rarely used in structural control applications. Gur et al (2019) also report this. They use in their study the rate dependent model of Helm and Haupt (2003) to simulate SMA dampers in steel buildings.…”

Behaviour of Smart Steel Column‐Beam Connection Under Blast Loading

“…The accuracy of the simplified approach is within 1% in comparison with the original Kingery results. Simplified Kingery Airblast Calculations approach recommended the following polynomial equation to determine the blast wave parameters, = [ + × (ln( )) + × (ln( )) 2 + × (ln( )) 3 + × (ln( )) 4 + × (ln( )) 5 + × (ln( )) 6 ]…”

“…The study showed that joint configuration equipped with NiTi SMA bolts experienced a fully flag-shaped hysteresis loop. Recently, Gur et al examined the effect of SMA bars to improve the seismic performance of steel frames equipped with SMA dampers [4]. The study observed the novelty of SMA comparing with other damper models, e.g., yielding damper.…”

Design and experimental analysis of a smart bearing using shape memory alloy springs

“…Phase transformations provided by SMA can be enjoyed to reduce vibration with significant results. One of the approaches is to dissipate energy through a hysteretic phase transformation of its microstructure (Gur et al, 2016(Gur et al, , 2019Mishra et al, 2013;Savi et al, 2011). Assuming that SMA behavior is similar to a damper, through this strategy it leads to employment as tuned mass damper (SMA-TMD), reaching proper results (Mishra et al, 2013;Savi et al, 2011).…”