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Earthquakes and Structures
  Volume 21, Number 5, November 2021 , pages 515-530
DOI: https://doi.org/10.12989/eas.2021.21.5.515
 


Performance based assessment for tall core structures consisting of buckling restrained braced frames and RC walls
Ali Alinaghi and Hamid Beiraghi

 
Abstract
    In a tall reinforced concrete (RC) core wall system subjected to strong ground motions, inelastic behavior near the base as well as mid-height of the wall is possible. Generally, the formation of plastic hinge in a core wall system may lead to extensive damage and significant repairing cost. A new configuration of core structures consisting of buckling restrained braced frames (BRBFs) and RC walls is an interesting idea in tall building seismic design. This concept can be used in the plan configuration of tall core wall systems. In this study, tall buildings with different configurations of combined core systems were designed and analyzed. Nonlinear time history analysis at severe earthquake level was performed and the results were compared for different configurations. The results demonstrate that using enough BRBFs can reduce the large curvature ductility demand at the base and mid-height of RC core wall systems and also can reduce the maximum inter-story drift ratio. For a better investigation of the structural behavior, the probabilistic approach can lead to in-depth insight. Therefore, incremental dynamic analysis (IDA) curves were calculated to assess the performance. Fragility curves at different limit states were then extracted and compared. Mean IDA curves demonstrate better behavior for a combined system, compared with conventional RC core wall systems. Collapse margin ratio for a RC core wall only system and RC core with enough BRBFs were almost 1.05 and 1.92 respectively. Therefore, it appears that using one RC core wall combined with enough BRBF core is an effective idea to achieve more confidence against tall building collapse and the results demonstrated the potential of the proposed system.
 
Key Words
    buckling restrained braces; core structures; incremental dynamic analysis; reinforced concrete wall
 
Address
Ali Alinaghi:Department of Civil Engineering, Mahdishahr Branch, Islamic Azad University, Mahdishahr, Iran

Hamid Beiraghi:Department of Civil Engineering, Mahdishahr Branch, Islamic Azad University, Mahdishahr, Iran
 

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