Comparative seismic fragility assessment of buckling restrained and self-centering (friction spring and SMA) braced frames

Anas Issa, M. Shahria Alam

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


In seismic regions, steel braced frames are one of the most commonly used seismic lateral force resisting systems for their reliable performance. This study presents a comparative seismic performance of different braced steel frames at their system levels. Three types of bracings for steel frames are investigated: Buckling Restrained Bracing (BRB), Superelastic Shape Memory Alloy (SMA) bar reinforced Piston Based Self Centering (named as PBSC) bracing, and Friction Spring Based Piston Bracing (named as SBPB). A methodology to evaluate the structural response of the building in a probabilistic framework is used. The procedure to estimate the probability of exceeding certain limit states conditioned on the ground motion intensity is applied to the structures. Emphasis is given to the estimation of the probability of exceedance of peak Interstory Drift Ratios (IDR). The peak interstory drift ratio provides a way to estimate the damage to structural components. For this purpose, four, six, eight, and twelve-story structures, designed with the three bracing types are used. A large number of Incremental Dynamic Analyses are performed to derive three-dimensional (3D) vulnerability functions that involve building heights and bracing types. This versatile 3D format enables the interpolation of results to arrive at the seismic fragilities of structures with different stories. The results show that the SBPB and PBSC frames outperformed the BRB frames in terms of damage probability.

Original languageEnglish
Article number055029
JournalSmart Materials and Structures
Issue number5
Publication statusPublished - May 2020
Externally publishedYes


  • Braced frames
  • Fragility
  • Incremental dynamic analysis
  • Piston
  • Sma
  • Spring

ASJC Scopus subject areas

  • Signal Processing
  • Civil and Structural Engineering
  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering


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