Numerical Study on Post-Fire Flexural and Shear Behavior of Reinforced Concrete Beams

Dongjun Han; Donghyuk Jung

doi:10.23310/PF.2025.2.3.186

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2025 Vol.2, Issue 3 Preview Page

Research Article

Numerical Study on Post-Fire Flexural and Shear Behavior of Reinforced Concrete Beams 화재 후 냉각된 철근콘크리트 보의 휨 및 전단 거동에 대한 수치해석 연구

20 August 2025. pp. 186-192

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Abstract

Recent large-scale fire incidents have highlighted the importance of ensuring the structural safety and post-fire residual capacity of reinforced concrete (RC) buildings. In particular, RC beams, where flexure and shear act in combination, undergo nonlinear structural responses due to high-temperature-induced material degradation and microcracking during the cooling phase, necessitating a quantitative assessment. This complexity makes experimental evaluation challenging, especially after the cooling phase, emphasizing the need for reliable numerical analysis. In this study, the structural performance of RC beams cooled to ambient temperature after fire exposure was analyzed using the nonlinear finite element analysis program ATENA. The analytical model was developed in conjunction with a heat transfer analysis, with primary variables set as the fire exposure duration and a/d ratio (the shear span to effective depth). By evaluating the load–displacement response, crack patterns, strength reduction under varying conditions, the study investigates the transition in failure modes after fire.

Keywords

Reinforced concrete beams

Fire exposure

Strength degradation

Residual strength

Failure mode

최근 빈번히 발생하는 대형 화재는 철근콘크리트 건축물의 구조 안전성과 화재 후 잔존 성능 확보의 중요성을 부각시키고 있다. 특히 휨과 전단이 복합적으로 작용하는 보 부재는 고온에 의한 재료 열화와 냉각 중 발생하는 미세 균열 등으로 인해 구조 응답이 비선형적으로 변화하므로 정량적 분석이 요구된다. 본 연구에서는 비선형 유한요소해석 프로그램인 ATENA를 활용하여, 화재 후 상온으로 냉각된 철근콘크리트 보의 구조 성능을 분석하였다. 해석 모델은 열전달 해석과 연계하여 구성되었으며, 주요 변수로 화재 노출 시간과 a/d(가력점과 지점 사이 거리를 단면 유효깊이로 나눈 값)를 설정하였다. 각 변수 변화에 따른 하중-변위 응답, 균열 양상, 강도 저감을 분석함으로써 화재 후 파괴 양상 전이를 규명하였다.

키워드

철근콘크리트 보

화재 노출

강도 저감

잔존 강도

파괴모드

References

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Information

Publisher :Korea Protective Facility Institute
Publisher(Ko) :한국방호시설학회
Journal Title :Protective Facility
Journal Title(Ko) :방호시설
Volume : 2
No :3
Pages :186-192
Received Date : 2025-07-26
Revised Date : 2025-08-13
Accepted Date : 2025-08-13
DOI :https://doi.org/10.23310/PF.2025.2.3.186

Protective Facility ISSN:3058-7816(Print) 3058-8618(Online) 방호시설

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