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Bulletin of Earthquake Engineering

, Volume 17, Issue 2, pp 781–802 | Cite as

Seismic performance of reinforced concrete frames retrofitted using external superelastic shape memory alloy bars

  • Y. I. Elbahy
  • M. A. YoussefEmail author
  • M. Meshaly
Original Research
  • 147 Downloads

Abstract

Pre-1970s designed and built reinforced concrete frame structures are considered unsafe when subjected to seismic loads. Insufficient anchorage of the beam reinforcement in the beam-column joints of these structures is considered a main deficiency. Newly built frame structures are seismically designed for safety, where high inelastic deformations can occur under moderate to strong earthquakes. Minimizing these inelastic deformations makes the structure repairable. One way to minimize these residual deformations is by using smart materials such as superelastic shape memory alloys (SMAs). In this paper, the seismic performance of RC frames retrofitted using external superelastic SMA bars is investigated and compared to the behaviour of a regular steel RC frame structure. Nonlinear time history analysis is performed for a six storey RC frame structure located in a high seismic region. After performing the analysis, two retrofitted frames are assumed and analyzed at the load intensities causing failure of the steel RC frame. The performance of the retrofitted frames is compared to the steel RC frame in terms of the damage level, the Maximum Inter-Storey Drift (MID) ratio, Maximum Residual Inter-Storey Drift (MRID), Maximum Roof Drift Ratio (MRDR), Residual Roof Drift Ratio (RRDR), and the earthquake intensity at collapse. Analysis results show improved seismic performance for the two retrofitted frames as compared to the original steel RC frame. This improvement was represented by lower level of damage at the same earthquake intensity; small reduction (10–15%) in the MID and MRDR values; significant reduction (50–70%) in the MRID and RRDR; and increased seismic capacity.

Keywords

Reinforced concrete (RC) Shape memory alloys (SMAs) Moment frame Seismic damage Seismic residual deformations Retrofitting 

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Copyright information

© Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.Department of Civil and Environmental EngineeringThe University of Western OntarioLondonCanada
  2. 2.Structural Engineering DepartmentAlexandria UniversityAlexandriaEgypt

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