Techno Press
Techno Press

Structural Engineering and Mechanics
  Volume 83, Number 6, September25 2022 , pages 811-824
DOI: https://doi.org/10.12989/sem.2022.83.6.811
 


Application of three-dimensional modified inclined braces to control soft-story buildings
Soroush Nodehi and Seyed Mehdi Zahrai

 
Abstract
    Despite its disadvantages, soft story can reduce the damage to the upper floors by concentrating drift in that specific story provided that large drifts are avoided. Gapped-Inclined Brace (GIB) with reduced P-delta effects and the control of soft story stiffness makes it possible to take advantage of the soft story in buildings and increase their capacity for energy dissipation. OpenSees software is used in this study to validate and modify the GIB model's shortcomings. Also, the analysis method for this element is changed for design. The modified element is evaluated in 3D analysis. Finally, to retrofit an existing building, this element is used. Based on the Iranian seismic code, a six-story reinforced concrete building is modelled and studied with 3D analysis. In this building, the construction shortcomings and elimination of infills on the ground floor cause the formation of a soft story. Results of nonlinear static analysis, nonlinear dynamic, and incremental dynamic analysis using both components of seismic acceleration applied to the structure at different angles and the fragility curves indicate the improvement of the retrofitted structure's performance using the modified element to reach the required performance level following the retrofit code.
 
Key Words
    3D nonlinear analysis, infills, modified gapped-inclined brace, retrofit, soft story
 
Address
Soroush Nodehi: School of Civil Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran
Seyed Mehdi Zahrai: School of Civil Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran; Department of Civil Engineering, University of Ottawa, Ottawa, Canada
 

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