• 한국터널지하공간학회 논문집
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• 제7권2호
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• pp.165-176
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• 2005

최근 전세계의 대형화재 사고이후, 터널안전에 관한 많은 연구들이 진행되고 있다. 특히 실물 및 축소모형 실험에 대한 다양한 연구가 진행되면서, 터널구조물에 대한 내화성능에도 많은 관심이 모아지고 있다. 이미 외국에서는 터널구조물의 내화성능에 대한 설계기준이나 권고안이 발표되고 있으나, 아직 국내에는 설계기준으로 마련되지 못하고 있다. 본 연구의 목적은 각 나라별 화재온도 (온도-시간) 곡선, 특히 ISO 834 표준온도곡선, HC곡선, RWS곡선, ZTV곡선, EBA곡선을 분석하여 국내의 도로, 지하철 및 철도터널의 내화성능 평가 기준에 적합한 화재특성을 도출하는데 있다.

• 한국구조물진단유지관리공학회 논문집
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• 제28권2호
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• pp.9-16
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• 2024

본 논문에서는 부피단위의 화재곡선을 단위면적당 화재곡선으로 구하여 화재곡선 식을 FDS 표면열방출율법에 대입할 수 있도록 하고자 하였다. 화재곡선을 총 연소특성시간을 고려하여 무차원으로 표현하였으며, 성장구간비 𝛽_i, 유지구간비 𝛽_s , 감쇄구간비 𝛽_d를 고려하여 화재강도에 대한 적절한 비율을 나타내도록 개선하였다. 또한, 질량증가에 따라 변화하는 연소 특성시간 보정함수 𝛾(m/m₀)를 도출하였으며, 질량비가 증가함에 따라 성장시간 값을 제어하기 위해 성장구간비 𝛽_i를 보정하는 함수 α_i(m/m₀)를 도출하였다. 이에 따라 기존 데이터를 활용하여 연소물의 기준질량을 선정하고, 질량 증가에 따른 화재곡선을 예측할 수 있는 식을 확립하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1426-1431
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• 2011

A study on the standardization of design fire HRR(heat release rate) curve was conducted for various railcar from the fire simulation or the fire tests. These standard curves are listed on the tunnel fire safety manual which will be used for the QRA(quantitative risk analysis) process of the long railway tunnels. The design fire curve is based with four simple factor representing the key of fire curve characteristics. Flashover time, maximum HRR and burn out time are the key factors of the design fire curve. Specially total heat release is decided by the burnable material amount in the car.

• 국제강구조저널
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• 제18권4호
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• pp.1470-1481
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• 2018

Building-level response to post-earthquake fire hazards in steel buildings has been assessed using primarily two-dimensional analyses of the lateral force resisting system. This approach may not adequately consider potential vulnerabilities in the gravity framing system. For this reason, three-dimensional (3D) finite element models of a 10-story case study building with perimeter moment resisting frames were developed to analyze post-earthquake fire events and better understand building response. Earthquakes are simulated using ground motion time histories, while Eurocode parametric time-temperature curves are used to represent compartment fires. Incremental dynamic analysis and incremental fire analysis procedures capture a range of hazard intensities. Findings show that the structural response due to earthquake and fire hazards are somewhat decoupled from one another. Regardless of the level of plastic hinging present in the moment framing system due to a seismic event, gravity column failure is the initiating failure mode in a fire event.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.51-54
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• 2005

Reinforced Concrete structures have been commonly regarded as fire-resisting constructions. In the case of high-strength concrete, however, the behavior of a concrete member under fire and after fire has characteristics in different way with normal strength concrete members because of spalling. The resonable evaluation about the residual strength and stiffness of members as well as material properties has to be conducted before reusing the fire-damaged structures or retrofitting or strengthening them. Therefore, the guideline is needed for evaluation the residual strength and stiffness. In this study, the fire test is conducted with parameters like concrete strength, fire time and cover thickness, etc. The loads-deflection curves are used for comparison and analysis with the parameters.

• 한국화재소방학회논문지
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• 제32권2호
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• pp.7-16
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• 2018

본 연구에서는 화재 시뮬레이션에 사용하기 위해 제안된 기존의 디자인 화재곡선을 일부 수정한 디자인 화재곡선을 제안하였다. ISO 9705 구획실 내 형성된 헵탄과 옥탄 풀화재를 대상으로 기존에 제안된 1-stage 디자인 화재곡선과 수정된 2-stage 디자인 화재곡선을 입력조건으로 적용하여 FDS와 CFAST를 이용한 시뮬레이션을 수행하고 실험결과와 비교하였다. FDS와 CFAST 시뮬레이션 결과에서 온도와 $O_2$, $CO_2$ 농도에 대해서 전체적으로 2-stage 디자인 화재곡선이 1-stage 디자인 화재곡선보다 잘 예측하였으며, 특히 화재 초기 성장단계에서 온도에 대한 예측은 2-stage 디자인 화재곡선의 결과가 더 합리적임을 확인하였다. 구획실 내 온도변화에 대한 FDS와 CFAST 시뮬레이션 결과는 상층부에 대해서는 비교적 합리적으로 예측하였고 두 계산결과에 차이가 크지 않았지만 하층부에 대해서는 두 계산 모두 너무 낮게 예측하였으며 두 계산결과에도 차이가 크게 나타나는 것을 알 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.371-374
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• 2003

The degree of changes in mechanical properties of fire-damaged reinforced concrete column depends mostly on sectional geometry, duration exposed to fire, and moisture containment. In order to reasonably assess the deterioration of structural capacity of fire-damaged reinforced concrete column, it is necessary to develop a theoretical model predicting column behavior based on nonlinear heat transfer equation in addition to the traditional mechanics. This research focuses on the development of theoretical model to predict moment-curvature relations of fire-damaged reinforced column. The model is used for the assessment of structural capacity of fire-damaged column in terms of moment-curvature relations and PM interaction curves.

• Structural Engineering and Mechanics
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• 제6권3호
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• pp.275-289
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• 1998

The objective of the paper is to present a method whereby the time required for a steel structure to sustain the effects of a prescribed temperature rise according to real fire curves can be calculated. The method is divided into two parts. The first part deals with the post-yield behaviour of steel structures at elevated temperatures. It takes into account the variation of the properties of steel material with temperature in an incremental elastoplastic analysis so that the safety factor of the structure under certain fire conditions can be assessed. The second part deals with the heat transfer problem of bare steel members in real fire. Factors affecting the heat transfer process are examined and a model for predicting the temperature variation with time under real fire conditions is proposed. This model results in more accurate temperature predictions for steel members than those obtained from previously adopted model.

• 한국안전학회지
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• 제37권4호
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• pp.101-112
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• 2022

Expanding urbanization practices result in high numbers of buildings being developed in city centers. This high building concentration leads to an increased fire risk, resulting in higher casualty rates and increased economic damages compared to fires in the past. The purpose of this study was to analyze the structural behavior of fire-damaged reinforced concrete buildings using analytical methods and to suggest methods of improving fire resistance in the event of a fire. Damage levels were measured using commercial software to apply the finite element method, ABAQUS, and MIDAS GEN to the dataset. Load-deflection curves were calculated using the effective area and moment of inertia of the fire-damaged columns provided by ABAQUS. The results of this analysis indicate that fire-damaged beams with experience greater deflection from indoor fires than they will from outdoor fires. Fires that occurred on the middle floors were more dangerous than those occurring on higher floors, and eccentrically loaded columns experienced more damage than axially loaded columns. The results indicate that these methods accurately predict structural behaviors of fire damaged concrete columns by considering fire exposure area and eccentric loading.

• Structural Engineering and Mechanics
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• 제77권5호
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• pp.661-672
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• 2021

In this article, the role of spans number and length in fire-resistance ratings (FRRs) of fireproofed steel frames are investigated. First, over a span-lengthening scenario, two one- and three-bay frames under the ISO834 fire are examined. It is shown that the FRRs of the frames rely highly on the changes made on their span length. Second, a building designed for three spans number of three, four, and five under natural fire is investigated. The beams are designed for two load-capacity-ratios (LCRs) of optimum and ultimate. The fire curves are determined through a probabilistic-based approach. It is shown that the structural vulnerability vastly increases while the number of spans decreases. The results show that for an optimum LCR, while the five-span frame can meet the required FRR in 87% of the fire scenarios, the four- and three-span frames can meet the required FRR in only 56%, and 50% of the fire scenarios, respectively. For an ultimate LCR, the five-, four- and three-span frames can meet the required FRR in 81%, 50%, and 37.5% of the fire scenarios, respectively. Functional solutions are then proposed to resolve the insufficiencies in the results and to rectify the application of the standard-based FRRs in the cases studied. The study here highlights how employing current standard-based FRRs can endanger structural safety if they are not connected to structural characteristics; a crucial hint specifically for the structural engineering community who may be not well familiar with the fundamentals of performance-based approaches.