• 한국화재소방학회논문지
• /
• 제24권2호
• /
• pp.31-37
• /
• 2010

비대칭 슬림플로어 합성보(Asymmetric Slimfloor Beam, 이하 ASB)는 비대칭 형강의 일부를 콘크리트 슬래브에 삽입한 합성보로서, 유럽에서 개발되었다. 근래 국내에서도 건축물의 층고저감, 물량감소, 내화 성능 증대 등의 목적으로 ASB의 연구가 진행되고 있다. 본 연구에서는 실험을 통하여 ASB의 내화성능을 확인하고, 열전달해석을 통하여 내화성능 시간에서의 모멘트 내력(Moment capacity)을 산정하였다. 그 결과를 바탕으로 방화석고보드와 ASB로 구성된 3시간 내화구조를 선정하고, 내화 성능을 검토하였다.

• 대한건축학회논문집:구조계
• /
• 제33권12호
• /
• pp.19-27
• /
• 2017

This paper is a study to improve the fire-resistance capacity of reinforced concrete (RC) members strengthened by fiber-reinforced-polymer (FRP). The fire resistance of the RC members strengthened by FRP was evaluated through high temperature exposure test. In order to improve the fire resistance of the FRP reinforcing method, a fire-proof board was attached to the reinforced FRP surface and then the high temperature exposure test was carried out to evaluate the improvement of the fire resistance performance. It was confirmed that the resistance to high temperature of NSMR could be improved somewhat compared with that of EBR from the experiment that exposed to high temperature under the load corresponding to 40% of nominal strength. When 30 mm thick fire-resistance (FR) board is attached to the FRP surface, the surface of the reinforced FRP does not reach $65^{\circ}C$, which is the glass transition temperature (GTT) of the epoxy until the external temperature reaches $480^{\circ}C$. In particular, when a high performance fire-proof mortar was first applied prior to FR board attachment, the FRP portion did not reach the epoxy glass transition temperature until the external temperature reached $600^{\circ}C$.

• 한국화재소방학회:학술대회논문집
• /
• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
• /
• pp.518-523
• /
• 2008

The modular beam made of steel material is wholly responsible for the load stress of the structure, therefore securing the fire-resistant capacity of the steel beam is absolutely important. The economic efficiency achieved by minimizing the thickness of the fire-resistant board attached, is also essential at the same time. Accordingly, a study of optimization of the thickness and interval of fire-resistant boards shall be conducted side by side. Therefore, in this study we have anticipated fire-resistant capacity by using a general-purpose S/W for finite elements, ABAQUS(6.7.1), in order to propose the configurable conditions that can secure the optimal fire-resisting capacity of modular beam. As a result of this analysis, it was impossible to secure the fire-resistance capacity when directly attaching fire-resistant board(30mm) on the modular board in accordance with KS F 2257-1, and the fire-resistant boards were manufactured in shape of module in consideration of its installation interval rather than direct application.

• Steel and Composite Structures
• /
• 제13권2호
• /
• pp.171-185
• /
• 2012

The calculation of fire resistance for a composite structural element comprises the calculation of the temperature within its cross-section and of the load bearing capacity, considering the evolution of the steel and concrete mechanical properties, function of the temperature. The paper proposes a method to calculate the bending capacity under ISO fire, for Slim Floor systems using asymmetric steel beams, with a wider lower flange or a narrow upper flange welded onto a half hot-rolled profile. The temperatures in the cross-section are evaluated by means of empirical formulas determined through a parametrical analysis, performed with the special purpose non-linear finite element program SAFIR. Considering these formulas, the bending capacity may be calculated, using an analytical approach to determine the plastic bending moment, for different fire resistance demands. The results obtained with this simplified method are validated through numerical analysis.

• Earthquakes and Structures
• /
• 제10권4호
• /
• pp.867-891
• /
• 2016

This paper addresses numerically the behavior of steel structures under Fire-after-Earthquake (FAE) loading. The study is focused on a four-storey library building and takes into account the damage that is induced in structural members due to earthquake. The basic objective is the assessment of both the fire-behavior and the fire-resistance of the structure in the case where the structure is damaged due to earthquake. The combined FAE scenarios involve two different stages: during the first stage, the structure is subjected to the ground motion record, while in the second stage the fire occurs. Different time-acceleration records are examined, each scaled to multiple levels of the Peak Ground Acceleration (PGA) in order to represent more severe earthquakes with lower probability of occurrence. In order to study in a systematic manner the behavior of the structure for the various FAE scenarios, a two-dimensional beam finite element model is developed, using the non-linear finite element analysis code MSC-MARC. The fire resistance of the structure is determined using rotational limits based on the ductility of structural members that are subjected to fire. These limits are temperature dependent and take into account the level of the structural damage at the end of the earthquake and the effect of geometric initial imperfections of structural members.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
• /
• pp.395-396
• /
• 2010

본 연구는 최근 국내 초고층 건물의 고강도콘크리트 화재시 내화성능 확보와 관련하여 자체 연구개발한 폴리믹스(PP섬유 + 폴리머분말)를 적용 80MPa 고강도 콘크리트에 대한 내화성능 확인 실험을 실시함으로써, 초고층 펌프압송이 가능한 초고층용 고내화콘크리트를 개발하는데 그 목적이 있다.

• Steel and Composite Structures
• /
• 제15권6호
• /
• pp.705-724
• /
• 2013

The behaviour of steel column at elevated temperature is significantly different than that at ambient temperature due to its changes in the mechanical properties with temperature. Reported literature suggests that steel column may become vulnerable when exposed to fire condition, since its strength and capacity decrease rapidly with temperature. The present study aims at investigating the lateral load resistance of non-insulated steel columns under fire exposure through finite element analysis. The studied parameters include moment-rotation behaviour, lateral load-deflection behaviour, stiffness and ductility of columns at different axial load levels. It was observed that when the temperature of the column was increased, there was a significant reduction in the lateral load and moment capacity of the non-insulated steel columns. Moreover, it was noted that the stiffness and ductility of steel columns decreased sharply with the increase in temperature, especially for temperatures above $400^{\circ}C$. In addition, the lateral load capacity and the moment capacity of columns were plotted against fire exposure time, which revealed that in fire conditions, the non-insulated steel columns experience substantial reduction in lateral load resistance within 15 minutes of fire exposure.

• 대한토목학회논문집
• /
• 제32권4A호
• /
• pp.245-253
• /
• 2012

본 연구에서는 장대터널이나 지하차도 등에 시공되는 횡류식 환기시스템을 구성하는 내화패널이 부착된 프리캐스트 풍도슬래브의 구조성능을 평가하기 위해서 실물모형 구조실험을 수행하였다. 또한, 내화패널의 휨강도와 Pull-off test를 통하여 내화패널과 슬래브의 부착성능 등의 기초성능을 우선적으로 확인하였다. 실물모형시험은 내화패널과 프리캐스트 PSC 슬래브의 정적 휨성능과 차량의 통행 시 발생하는 표면압력 이상의 하중에 대한 동적피로부착성능을 평가하였다. 동적피로하중 시험에서 내화패널과 PSC 슬래브 사이의 탈락이나 손상은 발생하지 않았으며, 정적재하시험에서도 매우 안정적인 거동을 보였으며, 하부에 부착된 내화패널의 탈락은 발생하지 않았다. 따라서 시공 중이나 시공 후 외부하중에 의해 내화패널의 탈락은 발생하지 않을 것으로 판단된다.

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

• 한국강구조학회 논문집
• /
• 제19권4호
• /
• pp.357-366
• /
• 2007

본 연구는 비대칭 H형강을 사용한 슬림플로어 보의 화재시 구조성능에 관한 실험 및 해석적 연구로서, 화재시 본 합성부재의 구조거동을 파악하여 합리적 내화설계의 자료를 얻는 것이 목적이다. 화재실험으로 계획된 여러 변수의 시험체를 제작하고 상온과 고온에서 휨실험을 수행하여 시간에 따른 온도분포, 하중-처짐 관계를 분석하였다. 해석적 방법은 설계된 단면에 대하여 완전 합성을 가정으로, 열전도 해석으로 온도분포를 구하고 재료의 잔존강도를 분할된 메쉬에 입력하여 휨강도를 예측하였다. 웨브의 두께와 깊이를 변수로 하여 슬림플로어 보의 화재시 휨내력을 고찰하였다.