• Steel and Composite Structures
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• 제13권4호
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• pp.309-325
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• 2012

The risk of progressive collapse in steel framed buildings under fire conditions is gradually rising due to the increasing use of combustible materials. The fire resistance of such steel framed buildings is evaluated by fire tests. Recently, the application of performance based fire engineering makes it easier to evaluate the fire resistance owing to various engineering techniques and fire science. The fire resistance of steel structural members can be evaluated by the comparison of the limiting temperatures and maximum temperatures of structural steel members. The limiting temperature is derived at the moment that the failure of structural member results from the rise in temperature and the maximum temperature is calculated by using a heat transfer analysis. To obtain the limiting temperatures for structural steel of grades SS400 and SM490 in Korea, tensile strength tests of coupons at high temperature were conducted. The limiting temperatures obtained by the tensile coupon tests were compared with the limiting temperatures reported in the literature and the results of column fire tests under four types of loading with different load ratios. Simple limiting temperature formulas for SS400 and SM490 steel based on the fire tests of the tensile coupons are proposed. The limiting temperature predictions using the proposed formulas were proven to be conservative in comparison with those obtained from H-section and hollow section column fire tests.

• 국제초고층학회논문집
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• 제2권1호
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• pp.39-48
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• 2013

The fire resistance performance of generic CFT columns has been verified through various tests and analyses and the columns are widely used for fire resistance designs abroad. In this study, 3 groups of specimens (Non-fire protection, reinforcement with steel fiber and fire resistance paint) are suggested in order to evaluate the fire resistance performance of interior anchor type concrete-filled steel tubular columns having efficient cross-sections through loaded heating tests. Axial deformation-time relationship and in-plane temperatures are compared to evaluate the fire resistance performance of the specimens associated with variables. Suggested from the fact that the interior anchors exposed to fire exert influence on fire resistance performance due to thermal expansion, the reinforcements using steel fiber and fire resistance paint are verified to mitigate contraction and improve fire resistance performance. The result obtained from the tests of interior anchor type concrete-filled tubular columns is expected to be used for effective fire resistance design in association with previously conducted studies.

• Steel and Composite Structures
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• 제8권6호
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• pp.491-510
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• 2008

This paper presents a plan and guidelines that were drawn for Korean based research carried out on the fire-resistance of CFT columns. This research was carried out by reviewing the Korean regulations related to the fire-resistance of CFT columns and examining studies which had been made in Korea as well as overseas. The first phase of the study plan was to compare the fire-resistance of square CFT columns without fire protection (obtained through fire-resistance tests and numerical analyses) with estimated values (obtained through fire-resistance design formulas proposed in Korea and overseas). This comparison provided conclusions as outlined below. Fire-resistance tests conducted in this study proved that, when the actual design load is taken into consideration, square CFT columns without fire protection are able to resist a fire for more than one hour. A comparison was made of test and analysis results with the fire-resistance time based on the AIJ code, the AISC design formula and the estimation formula suggested for Korea. The results of this comparison showed that the test and analysis results for specimens SAH1, SAH2-1, SAH2-2 and SAH3 were almost identical with the AIJ code, the AISC design formula and estimation formula. For specimens SAH4 and SAH5, the estimation formula was more conservative than the AIJ code and the AISC design formula. It was necessary to identify the factors that have an influence on the fire-resistance of CFT columns without fire protection and to draw fire-resistance design formulas for these columns. To achieve this, it is proposed that numerical analyses and tests be conducted in order to evaluate the fire-resistance of circular CFT columns, the influence of eccentricity existing as an additional factor and the influence of the slenderness ratio of the columns. It is also suggested that the overall behavior of CFT structures without fire protection within a fire be evaluated through analysis simulation.

• Steel and Composite Structures
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• 제12권4호
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• pp.325-350
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• 2012

Concrete filled steel hollow structural sections (CFSs) are an efficient, sustainable, and attractive option for both ambient temperature and fire resistance design of columns in multi-storey buildings and are becoming increasingly common in modern construction practice around the world. Whilst the design of these sections at ambient temperatures is reasonably well understood, and models to predict the strength and failure modes of these elements at ambient temperatures correlate well with observations from tests, this appears not to be true in the case of fire resistant design. This paper reviews available data from furnace tests on CFS columns and assesses the statistical confidence in available fire resistance design models/approaches used in North America and Europe. This is done using a meta-analysis comparing the available experimental data from large-scale standard fire tests performed around the world against fire resistance predictions from design codes. It is shown that available design approaches carry a very large uncertainty of prediction, suggesting that they fail to properly account for fundamental aspects of the underlying thermal response and/or structural mechanics during fire. Current North American fire resistance design approaches for CFS columns are shown to be considerably less conservative, on average, than those used in Europe.

• 한국구조물진단유지관리공학회 논문집
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• 제22권5호
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• pp.72-81
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• 2018

방화구획 내 벽체에는 콘크리트, 조립식 패널, 건식벽체 등을 사용한 내화구조가 주로 적용되고 있으나 근래에 들어 시야 확보 및 미적 관점에 대한 관심이 증가하여 유리로 구성된 벽체의 수요가 발생하고 있다. 본 연구에서는 차열 유리를 적용한 스틸 내화벽체에 관한 것으로써 내부 방화구획에 적용 가능한 60분 내화벽체와 외부 벽체 및 커튼월에 적용 가능한 90분 내화벽체에 대하여 내화시험 및 성능분석을 수행하였다. 시험 결과, 각 시험체의 요구 내화성능을 충족하는 것으로 나타났으며, 추가적으로 유한요소해석을 통한 유리벽체의 내화성능을 평가하였으며 그 결과 1차적으로 시험체의 내화성능을 예측하는 것이 가능한 것으로 판단되었다.

• Steel and Composite Structures
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• 제43권4호
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• pp.483-500
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• 2022

Cold-formed steel wall panels sheathed with gypsum plasterboard have shown superior thermal and structural performance in fire. Recent damage caused by fire events in Australia has increased the need for accurate fire resistance ratings of wall systems used in low- and mid-rise construction. Past fire research has mostly focused on light gauge steel framed (LSF) walls under uniform axial compression and LSF floors under pure bending. However, in reality, LSF wall studs may be subject to both compression and bending actions due to eccentric loading at the wall to-roof or wall-to-floor connections. In order to investigate the fire resistance of LSF walls under the effects of these loading eccentricities, four full-scale standard fire tests were conducted on 3 m × 3 m LSF wall specimens lined with two 16 mm gypsum plasterboards under different combinations of axial compression and lateral load ratios. The findings show that the loading eccentricity can adversely affect the fire resistance level of the LSF wall depending on the magnitude of the eccentricity, the resultant compressive stresses in the hot and cold flanges of the wall studs caused by combined loading and the temperatures of the hot and cold flanges of the studs. Structural fire designers should consider the effects of loading eccentricity in the design of LSF walls to eliminate their potential failures in fire.

• Structural Engineering and Mechanics
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• 제69권2호
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• pp.193-204
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• 2019

This paper presents results from experimental and numerical studies on the response of steel-concrete composite box bridge girders under certain localized fire exposure conditions. Two composite box bridge girders, a simply supported girder and a continuous girder respectively, were tested under simultaneous loading and fire exposure. The simply supported girder was exposed to fire over 40% of its span length in the middle zone, and the two-span continuous girder was exposed to fire over 38% of its length of the first span and full length of the second span. A measurement method based on comparative rate of deflection was provided to predict the failure time in the hogging moment zone of continuous composite box bridge girders under certain localized fire exposure condition. Parameters including transverse and longitudinal stiffeners and fire scenarios were introduced to investigate fire resistance of the composite box bridge girders. Test results show that failure of the simply supported girder is governed by the deflection limit state, whereas failure of the continuous girder occurs through bending buckling of the web and bottom slab in the hogging moment zone. Deflection based criterion may not be reliable in evaluating failure of continuous composite box bridge girder under certain fire exposure condition. The fire resistance (failure time) of the continuous girder is higher than that of the simply supported girder. Data from fire tests is successfully utilized to validate a finite element based numerical model for further investigating the response of composite box bridge girders exposed to localized fire. Results from numerical analysis show that fire resistance of composite box bridge girders can be highly influenced by the spacing of longitudinal stiffeners and fire severity. The continuous composite box bridge girder with closer longitudinal stiffeners has better fire resistance than the simply composite box bridge girder. It is concluded that the fire resistance of continuous composite box bridge girders can be significantly enhanced by preventing the hogging moment zone from exposure to fire. Longitudinal stiffeners with closer spacing can enhance fire resistance of composite box bridge girders. The increase of transverse stiffeners has no significant effect on fire resistance of composite box bridge girders.

• 한국화재소방학회논문지
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• 제29권4호
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• pp.1-6
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• 2015

강구조용 내화뿜칠재는 내화구조로 인정을 받아야 사용할 수 있는데 내화뿜칠재 인정시 보와 기둥이 분리되어 평가 및 인정되고 있다. 보와 기둥의 내화시험 표준시험체는 단면형상계수 등이 상이하므로 내화피복 두께산정방법(KS F 2848)에 따르면 동일피복재를 사용하는 경우 동일성능의 보용 뿜칠재와 기둥용 뿜칠재는 피복두께가 상이할 것으로 예상할 수 있다. 그러나 현재 인정이 유효한 내화뿜칠재의 보 기둥 피복두께는 제품별로 서로 동일하거나 매우 유사하다. 그렇다면 동 뿜칠재의 내화구조 인정을 위한 성능시험시 보와 기둥의 강재평균온도에 차이가 있었을 것이라고 추정해 볼 수 있다. 본 연구를 통하여 보용 또는 기둥용 내화뿜칠재의 강재평균온도를 비교분석하여, 보용 기둥용으로 분리하여 평가 및 인정하고 있는 현 제도를 검토해 보고자 한다.

• 한국재난정보학회 논문집
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• 제20권2호
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• pp.419-429
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• 2024

연구목적: 소방용 배관 보온재의 불연성능 강화와 제연덕트 보온재의 내열성능 향상을 위해 AES소재 단열재의 성능을 시험을 통해 배관보온재 및 제연덕트 보온재에 적합성을 검증하고자 한다. 연구방법: AES 단열재에 대해 불연성능과 내열성능, 단열성능을 시험을 통해 검증한다. 연구결과: '건축물 마감재료의 난연성능 및 화재 확산 방지구조 기준'에 근거하여 불연성 및 가스 유해성 시험 결과 불연성능을 확인하였고, 내화성능 표준시험 결과 내화성능도 확인하였다. 또한, 건축용 단열시험으로 단열성능도 검증하였다. 결론: 본 연구에서 AES 계열 무기질 성분 단열재에 대한 성능시험으로 불연성능, 내화성능, 단열성능이 입증됨에 따라 건축물의 화재확산 방지성능을 개선하는데 좋은 대안이 될 것으로 사료된다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.61-64
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• 2008

Applying fire resistive coating to steel members is one of the general methods to secure fire resistance performance of steel members. And intumescent coating system is currently one of methods giving fire resistance to steel members. Intumescent coating system for fire resistance, however, has undesirable weaknesses that fire resistance performance of steel members is being deteriorated due to cracks and falling-offs of the coverings as time goes after completion of the coverings to the members. This study is designed to understand changes in fire resistance performance of intumescent coating system through follow-up tests on temperature of unexposed surface for the domestic intumescent coating system.