Techno Press
Techno Press

Structural Engineering and Mechanics
  Volume 97, Number 5, March10 2026 , pages 643-666
DOI: https://doi.org/10.12989/sem.2026.97.5.643
 


Performance assessment and fragility analysis of base-isolated steel frames with semi-rigid connections
Said H. Boukhalkhal, Soumia Taleb, Abd Nacer T. Ihaddoudène, Abdallah Y. Rahmani

 
Abstract
    This research presents a numerical study to investigate the influence of node flexibility on the seismic performance and fragility of medium- to high-rise base-isolated buildings. A computational program was also developed to design the isolator bearings used in the models, enabling a comprehensive evaluation of both structural response and isolation performance. The results confirm that seismic isolation effectively reduces inter-story drifts and minimizes both structural and non-structural damage. Moreover, semi-rigid connections were found to increase target displacements up to twice those of rigid connections while reducing shear forces by approximately 30%. The study further indicates that isolation systems are particularly effective for low- and medium-rise structures, whereas taller buildings may experience a risk of shear failure at the bearing supports, where semi-rigid connections can provide a more favorable solution. Overall, the findings offer valuable insights into the interplay between node flexibility and seismic isolation, highlighting both the advantages and limitations of these strategies for enhancing the seismic resilience of medium- to high-rise buildings.
 
Key Words
    base-isolated structures; fragility analysis; HRB isolator; pushover analysis; semi-rigid connections
 
Address
Said H. Boukhalkhal: Faculty of Civil Engineering, University of Sciences & Technology Houari Boumediene of Algiers (USTHB), BP.32 El-Alia, Bab Ezzouar, 16111, Algiers, Algeria; Department of Civil Engineering, University of Djelfa, Djelfa, 17000, P.O.B. 3117, Algeria; Laboratory of Mechanics and Materials Development, University of Djelfa, PO Box 3117, 17000, Djelfa, Algeria
Soumia Taleb: Department of Civil Engineering, University of Djelfa, Djelfa, 17000, P.O.B. 3117, Algeria; Laboratory of Mechanics and Materials Development, University of Djelfa, PO Box 3117, 17000, Djelfa, Algeria
Abd Nacer T. Ihaddoudène: Faculty of Civil Engineering, University of Sciences & Technology Houari Boumediene of Algiers (USTHB), BP.32 El-Alia, Bab Ezzouar, 16111, Algiers, Algeria
Abdallah Y. Rahmani: Department of Civil Engineering, University of Djelfa, Djelfa, 17000, P.O.B. 3117, Algeria
 

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