Seismic assessment of bridge structures isolated by a shape memory alloy/rubber-based isolation system

Abstract

This paper explores the effectiveness of shape memory alloy (SMA)/rubber-based isolation systems for seismic protection of bridges against near-field earthquakes by performing a sensitivity analysis. The isolation system considered in this study consists of a laminated rubber bearing, which provides lateral flexibility while supplying high vertical load-carrying capacity and an auxiliary device made of multiple loops of SMA wires. The SMA device offers additional energy dissipating and re-centering capability. A three-span continuous bridge is modeled with the SMA/rubber-based (SRB) isolation system. Numerical simulations of the bridge are conducted for various near-field ground motions that are spectrally matched to a target design spectrum. The normalized forward transformation strength, forward transformation displacement and pre-strain level of the SMA device, ambient temperature and the lateral stiffness of the rubber bearings are selected as parameters of the sensitivity study. The variation of seismic response of the bridge with considered parameters is assessed. Also, the performance of the SRB isolation system with optimal design parameters is compared with an SMA-based sliding isolation system. The results indicate that the SRB isolation system can successfully reduce the seismic response of highway bridges; however, a smart isolation system that combines sliding bearings together with an SMA device is more efficient than the SRB isolation system.

A State-of-the-Art Review of Seismic Isolation Technology in Bridge Engineering

“…In recent years the SMA has attract comprehensive attention in building and bridge vibration control field. Hurlebaus (2011a and2011b) have analyzed the parameter sensitivity and effectiveness about the combined isolation system made of SMA with LNRB or flat steel-PTFE sliding friction bearing in bridge structures.…”

Analytical Description of SMA Actuator Dynamics based on Fermi-Dirac Function

“…They are used in civil engineering to protect buildings or bridges exposed to earthquakes (e.g. as seismic protection system) [9]. Passive SMA actuators can suppress vibrations.…”

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

“…The two most prominent properties of SMAs are the shape memory effect, which is the ability of the material to return to its original shape after heating, and superelastic effect, which is the ability of the material to recover its large inelastic deformations upon the removal of the load. 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.…”