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Seismic Performance of concrete buildings reinforced with superelastic shape memory alloy rebars Hossain, Afrin

Abstract

In this study, superelastic shape memory alloy (SMA) rebar was used as reinforcement in the plastic hinge regions of reinforced concrete beams. Twenty different reinforced concrete (RC) moment resisting frames of three different heights (3, 6, and 8-storys) were used in this study where SMA is gradually introduced from level 1 to the top most floor. The frames were designed according to the recent code of (CSA A23.3-04 2004) and assumed to be located in the high seismic zone of Western Canada. Nonlinear static pushover analysis and incremental dynamic analysis, (IDA) considering 20 earthquake records were performed to determine the best distribution of SMA rebars and investigate the seismic performance factors (SPFs). The best distribution of SMA rebars was determined based on the results of the seismic performance of steel and SMA frames obtained from the nonlinear incremental dynamic analysis (IDA) in terms of the maximum inter-story drift ratio (Max.ISDR), maximum residual inter-story drift ratio (Max.RISDR), roof drift ratio (RoofDR) and residual roof drift ratio (RRoofDR). The seismic performance of the SMA RC frames was evaluated where the acceptability of a trial value of the response modification coefficient, R factor was assessed and appropriate values of system overstrength factor, Ω0 and the deflection amplification factor, Cd were determined. The recent FEMA P695 (2009) methodology, was followed for this purpose. The obtained results on SPFs of all individual frames from nonlinear static pushover analysis (POA) and incremental non-linear dynamic analysis, (IDA) represent that the proposed seismic factors were within the range of permissible limit and when subjected to maximum considered earthquake, (MCE) a sufficient margin could be provided against collapse. Steel-SMA-RC frames experienced 4%-17% lower probability of collapse compared to the steel-RC frames.

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