Damping-Ductility Relationship for Performance Based Seismic Design of Shape Memory Alloy Reinforced Concrete Bridge Pier

In performance based seismic design of structures, estimating the equivalent viscous damping (EVD) using a damping-ductility relationship is a major step. The seismic response of Shape Memory Alloy (SMA) reinforced concrete (RC) bridge pier is different from its traditional steel reinforced or post-tensioned counterparts. Due to its significantly different hysteretic response and material properties, it is necessary to estimate the EVD of SMA-RC pier and establish the damping-ductility relationship. An error in the estimation of equivalent viscous damping can lead to significant errors in the ductility demand of the designed pier. This study aims to develop expressions for equivalent viscous damping and damping-ductility relationship for SMA reinforced bridge pier when SMA rebars are used in the plastic hinge region of the bridge pier. New equivalent damping relations for five different bridge piers reinforced with five different types of SMAs have been developed. Nonlinear dynamic time history analyses were conducted on five different SMA-RC bridge piers using 100 ground motions. The accuracy of the new equivalent damping relation was assessed to ensure the applicability of the proposed relationships. Finally, a general expression was developed that can assist in estimating equivalent viscous damping for performance based seismic design of SMA reinforced bridge pier.

[1]  M. Shahria Alam,et al.  Shape memory alloy wire-based smart natural rubber bearing , 2013 .

[2]  K. Ishida,et al.  Superelastic Effect in Polycrystalline Ferrous Alloys , 2011, Science.

[3]  Yoshikazu Araki,et al.  Feasibility of Cu–Al–Mn superelastic alloy bars as reinforcement elements in concrete beams , 2013 .

[4]  M. Ghassemieh,et al.  Seismic control of concrete shear wall using shape memory alloys , 2012 .

[5]  M. Menegotto.  Method of Analysis for Cyclically Loaded R. C. Plane Frames Including Changes in Geometry and Non-Elastic Behavior of Elements under Combined Normal Force and Bending , 1973 .

[6]  Eduardo Miranda,et al.  Evaluation of approximate methods to estimate maximum inelastic displacement demands , 2002 .

[7]  E. Sacco,et al.  A Superelastic Shape-Memory-Alloy Beam Model , 1997 .

[8]  Moncef L. Nehdi,et al.  Analytical prediction of the seismic behaviour of superelastic shape memory alloy reinforced concrete elements , 2008 .

[9]  M. Shahria Alam,et al.  Erratum to: Seismic fragility assessment of SMA-bar restrained multi-span continuous highway bridge isolated by different laminated rubber bearings in medium to strong seismic risk zones , 2012, Bulletin of Earthquake Engineering.

[10]  K. Ishida,et al.  Ferrous Polycrystalline Shape-Memory Alloy Showing Huge Superelasticity , 2010, Science.

[11]  Moncef L. Nehdi,et al.  Utilizing shape memory alloys to enhance the performance and safety of civil infrastructure: a review , 2007 .

[12]  Mervyn J. Kowalsky,et al.  Equivalent Damping in Support of Direct Displacement-Based Design , 2004 .

[13]  J. Mander,et al.  Theoretical stress strain model for confined concrete , 1988 .

[14]  Mervyn J. Kowalsky,et al.  Displacement-based seismic design of structures , 2007 .

[15]  M. Shahria Alam,et al.  Seismic Fragility Assessment of Concrete Bridge Pier Reinforced with Superelastic Shape Memory Alloy , 2015 .

[16]  M. Saiid Saiidi,et al.  Cyclic Response of Concrete Bridge Columns Using Superelastic Nitinol and Bendable Concrete , 2009 .

[17]  Reginald DesRoches,et al.  CYCLIC PROPERTIES OF SUPERELASTIC SHAPE MEMORY ALLOY WIRES AND BARS , 2004 .

[18]  T. Paulay,et al.  Seismic Design of Reinforced Concrete and Masonry Buildings , 1992 .