Design and analysis of braced frames with shape memory alloy and energy-absorbing hybrid devices

A hybrid seismic device that provides both energy-absorbing and re-centering capabilities to overcome external forces is developed and evaluated. The hybrid device is composed of three main components: (1) a set of re-centering wires fabricated from shape memory alloy (SMA) material, (2) two energy-absorbing struts, and (3) two high-strength steel tubes to guide the movement of the hybrid device. The SMA wires are located within the guiding high-strength steel tubes and designed to be sufficiently long such that their deformation strain is within the 6% target strain limit. A conservative value of 6% strain, instead of 8%, or 10%, is adopted to (1) avoid the SMA stiffening phase that increases strength up to 5 times that of its forward transformation yield forces, resulting in a serious damage to the adjacent structural members, and (2) to retain the full re-centering capability of the SMA wires even when the hybrid device is under large displacement. The energy-absorbing struts are pin-connected outside of the guiding steel tubes and may be fabricated of mild steel or low strength aluminum. To reduce the possibility of buckling in the energy-absorbing struts when subjected to compression, they are designed to be stocky and seismically compact, or buckling restrained. An optimal proportion of the SMA wires and energy-absorbing struts is formulated such that the hybrid device retains re-centering capability, while maximizing energy dissipation. Results obtained through the seismic analysis reveal that the hybrid braced frame system exhibits a similar energy dissipation capacity to the buckling restrained braced system, while also having excellent re-centering capabilities.

[1]  Roberto T. Leon,et al.  Analytical Study of SDOF Systems with Superelastic Shape Memory Alloy Properties , 2008 .

[2]  Donatello Cardone,et al.  Implementation and testing of passive control devices based on shape memory alloys , 2000 .

[3]  Davide Fugazza,et al.  Use of Shape-Memory Alloy Devices in Earthquake Engineering: Mechanical Properties, Advanced Constitutive Modelling and Structural Applications , 2005 .

[4]  Krzysztof Wilde,et al.  Base isolation system with shape memory alloy device for elevated highway bridges , 2000 .

[5]  Reginald DesRoches,et al.  Seismic retrofit of simply supported bridges using shape memory alloys , 2002 .

[6]  Roberto T. Leon,et al.  Pushover Response of a Braced Frame with Suspended Zipper Struts , 2008 .

[7]  J. Perkins,et al.  Shape Memory Effects in Alloys , 1975 .

[8]  Jason McCormick,et al.  Cyclic Behavior of Shape Memory Alloys: Materials Characterization and Optimization , 2006 .

[9]  T. W. Duerig,et al.  Engineering Aspects of Shape Memory Alloys , 1990 .

[10]  Songye Zhu,et al.  Performance Based Seismic Design of Steel Braced Frame System with Self-Centering Friction Damping Brace , 2008 .

[11]  Reginald DesRoches,et al.  Effect of hysteretic properties of superelastic shape memory alloys on the seismic performance of structures , 2007 .

[12]  Mehdi Ghassemieh,et al.  Implementation of shape memory alloy dampers for passive control of structures subjected to seismic excitations , 2007 .

[13]  Chin-Hsiung Loh,et al.  Experimental Investigation of Super-Elastic Semi-Active Damping for Seismically Excited Structures , 2008 .

[14]  P. C Tsopelas,et al.  NCEER - Taisei Corporation Research Program on Sliding Seismic Isolation Systems for Bridges : Experimental and analytical study of a system consisting of sliding bearings and fluid restoring force/damping devices , 1994 .

[15]  S. Bruno,et al.  Comparative response analysis of conventional and innovative seismic protection strategies , 2002 .

[16]  Johnny Sun,et al.  Development of Ground Motion Time Histories for Phase 2 of the FEMA/SAC Steel Project , 1997 .

[17]  Robert E. Bachman,et al.  The Use of the Energy Dissipating Restraint for Seismic Hazard Mitigation , 1993 .

[18]  Ramesh Chandra,et al.  Active shape control of composite blades using shape memory actuation , 2001 .

[19]  E. Sacco,et al.  A one-dimensional model for superelastic shape-memory alloys with different elastic properties between austenite and martensite , 1997 .

[20]  Roberto T. Leon,et al.  Design and behavior of zipper-braced frames , 2008 .

[21]  Chin-Hsiung Loh,et al.  GA-optimized fuzzy logic control of a large-scale building for seismic loads , 2008 .

[22]  N. Null.  Minimum Design Loads for Buildings and Other Structures , 2003 .