Analogy of the seismic behavior of composite frames (concrete columns and steel beams) with steel and reinforced concrete frames in low-rise, mid-rise, and high-rise buildings

Articles in Press

Document Type : Original Article

Authors

1 Professor, School of Civil Engineering, Tehran University, Tehran, Iran.

2 Master, School of Civil Engineering, Tehran University, Tehran, Iran.

3 Master, Department of Civil Engineering, Sharif University of Technology, Tehran, Iran.

10.22065/jsce.2024.413941.3208

Abstract

Steel Beam - Reinforced Concrete Column (RCS) frames are a new seismic load-bearing system. However, there has been limited research comparing the behavior of RCS frames to steel and concrete frames. This study aimed to fill that gap by examining moment frames in composite (RCS), steel, and reinforced concrete forms in three different height categories: 5, 10, and 20 stories. The frames were seismically loaded according to ASCE7-22 code and then designed and optimized based on AISC360-22 and ACI318-19 codes. Two-dimensional frames were extracted from the designed three-dimensional structures and subjected to nonlinear modeling in the finite element software OpenSees. Initial static nonlinear analyses were conducted to evaluate preliminary seismic responses in the post-yield regions, followed by incremental dynamic analyses on all models. The collapse states of the models were compared using fragility curves. The study found that the seismic intensity index for steel frames is roughly 1.27 times greater than that for RCS frames. Similarly, the intensity index in RCS frames is about 0.9 times that of concrete frames. Additionally, the collapse-related behavior in RCS frames was found to be more desirable than in concrete frames as the number of stories increases. At a given seismic intensity, the probability of collapse is lower in RCS frames than in concrete frames. The modified collapse margin ratio in ten-story frames and twenty-story RCS frames, compared to the concrete frame, is about 1.1 and 1.26, respectively. In conclusion, the study shows that RCS frames have a more favorable seismic performance compared to steel and concrete frames, especially as the number of stories increases. This research contributes to a better understanding of the behavior of RCS frames in seismic conditions.

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Journal of Structural and Construction Engineering

Articles in Press, Accepted Manuscript
Available Online from 01 January 2024

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History

  • Receive Date: 03 September 2023
  • Revise Date: 30 November 2023
  • Accept Date: 01 January 2024

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