• Journal of the Korea Concrete Institute
• /
• v.21 no.4
• /
• pp.473-480
• /
• 2009

The 180 minutes fire test based on the standard curve of ISO-834 were conducted on three RC column specimens with different constant axial loading ratios to evaluate the fire performance of fiber cocktail (polypropylene+steel fiber) reinforced high strength concrete column. The columns were tested under three loading levels as 40%, 50%, and 61% of the design load. No explosive spalling has been observed and the original color of specimen surface has been changed to light pinkish grey. The maximum axial displacements of three specimens were 1.5~2.2 mm. There was no reduction in load bearing capacity of each specimen exposed to fire and no effect were observed on the fire performance within 61% of the design load. The tendencies of the results with loading, such as the temperature distribution of in concrete and the changes in temperature rise due to the water vaporization in concrete, are very similar to those without loading. The final temperatures of steel rebar after 180 minutes of fire test resulted in 491.4${^{\circ}C}$ for corner rebar, 329.0${^{\circ}C}$ for center rebar, and 409.8${^{\circ}C}$ for total mean of steel rebar. The difference of mean temperature between corner and center rebar was 153.7${^{\circ}C}$ㅍ. The tendency of temperature rise in concrete and steel rebar changed after 30~50 minutes from the starting time of the fire test because the heat energy influx into corner rebar is larger than that into center rebar. The cause of decrease in temperature rise was due to the water vaporization in concrete, the lower temperature gradient of the concrete with steel and polypropylene fiber cocktails, the moisture movement toward steel rebars and the moisture clogging.

• Journal of the Korea Institute of Building Construction
• /
• v.15 no.3
• /
• pp.273-280
• /
• 2015

In this study, tests were carried out to find out a method to ensure the fire resistance performance of high-performance non-refractory coating CFT columns. For the high performance concrete fabrication with 100MPa, blast furnace slag(BS) and steel and nylon fibers were used. It was found that the partial replacement with BS improved the fire resistance performance of the concrete. Based on the results of lab tests, the large fire test was conducted. For this test, the CFTs with the size of ${\phi}500{\times}4,200mm$ and the reinforcement of SS 400 steel were prepared and they were subjected to a loading condition. It was found that as the level of load increased, the level of fire resistance decreased. For example, In with the loading condition of 2000kN the CFT could resist the fire for over 240 minutes, whereas, with the loading condition of 3,000kN and 4000kN applying to equivalent CFTs, the resisting time against fire were 184 minutes, and 120 minutes, respectively.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2013.04a
• /
• pp.109-110
• /
• 2013

국내에서 최초로 장스팬 프리플렉스 합성보에 대한 내화성능을 평가하고 그 결과를 분석하였다. 내화성능평가는 재하시험과 비재하시험을 대상으로 하였으며, 콘크리트 폭렬의 영향성과 뿜칠피복재의 단열효과에 의한 성능확보 요인을 분석하였다. 본 논문은 국내 최장 합성보의 내화구조 인정신청에 따른 성능확인 결과이며, 향후 다양한 합성보 개발에 참고가 될 수 있을 것으로 기대한다.

• Fire Science and Engineering
• /
• v.24 no.6
• /
• pp.82-88
• /
• 2010

Major structural elements such as columns and beams are designed to withstand the vertical and horizontal loads. Futhermore, when the structural elements were engulfed with fire the structural stability should be stand without failure. The beams have been developed in aspects of structural stability but an evaluation of fire performance was not done. So the data of fire resistance performance of beams filled with concrete at web on H-section is not known. The purpose of this paper is to analyse the correlation between temperature analysis and fire test with the beams and to show the fire resistance performance with two methods.

• Journal of Korean Society of Steel Construction
• /
• v.22 no.6
• /
• pp.523-532
• /
• 2010

Concrete-filled square steel tube (CFT) columns have inherently high fire resistance and load-bearing capacity. Nevertheless, it is sometimes necessary to improve their fire resistance using external fire protection. This paper presents the experimental results of the temperature distribution of CFT columns with fire protection. A fire load test was carried out by exposing small-scale specimens to heat in an electric furnace that was especially built for testing loaded columns. The temperature distribution of CFT columns under constant axial loads was determined, as were its significant parameters, such as the types of fire protection and thickness, the thickness of the square CFT, and the fire duration times. The results of this study showed the temperature distribution of each specimen of the electric furnace and the temperature distribution properties of concrete and steel. In addition, the axial displacement and local buckling behavior of CFT columns based on temperature changes was observed.

• Journal of Korean Society of Steel Construction
• /
• v.25 no.4
• /
• pp.379-388
• /
• 2013

This paper aims to experimentally investigate the fire resistance of U-shaped hybrid composite beams protected by spay and paint insulations. Subjected to two and three hours of the Standard ISO fire, the flexural performance of 4.4m beams with/without imposed loadings was examined with respect to failure criteria such as deflection and deflection rate of the mid-span and temperatures measured in the steel section. The results demonstrated that the proposed configuration of the composite beam is able to achieve a very competitive 3-hour fire resistance rating in economical aspects.

• Journal of Korean Society of Steel Construction
• /
• v.12 no.6
• /
• pp.759-767
• /
• 2000

In this study, the time dependent internal stress changes of a Concrete Filled Steel Tube(CFT) column during a fire test were quantitatively analyzed. The strain ratio of a CFT column on the different loads was measured by tensile strength tests in terms of yield strength, tensile strength average extensibility and elasticity modulus. To understand the internal material properties change of concrete in CFT column damaged due to a fire, the compressive strength and elastic modulus tests were measured on a core sample from the center of the steel tube after the fire test. The elastic modulus test measured the strain from the stress. To determine the fire temperature of the test material, a differential thermal analysis was done. From the tested result, the gained data were conducted and an analysis method was suggested. The purpose of this work is to suggest a basic data for structure regulation enactments of the internal fire design of CFT.

• Fire Science and Engineering
• /
• v.24 no.4
• /
• pp.55-61
• /
• 2010

Fire resistance is very essential for all buildings to save peoples who live within buildings or use and to protect the properties when the buildings are covered with fire. The fire resistance were evaluated by loading or nonloading fire tests which are known very expensive and require lots of time. That causes the lacks of research activities and there are only small cases of fire resistance. The purposes of this paper are to analyze the temperature analysis for various structural elements such as columns and beams those are can be applied to buildings and to suggest the resonable fire protective thickness of concrete slab according to the required fire resistance time.

• Fire Science and Engineering
• /
• v.23 no.2
• /
• pp.27-35
• /
• 2009

In this study, the fire resistance performance of a simple support composite beam, which was sprayed with fire protection coatings, was evaluated. Primary valuables of the study are loading and unloading, shape of composite beam and metal lath of the web. The thickness of the fire protection coating to the three hour resistance is 40mm, but the fire resistance test was performed with 25mm coatings. The test result showed that TSC composit beams with 25mm fire protection coatings can resist on fire for three hours at the both loading and unloading tests. Average and maximum temperatures were less than $250^{\circ}C$ and $310^{\circ}C$ respectively, compared with the standard temperatures for fire resistance on the loading and unloading tests.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.4A
• /
• pp.245-253
• /
• 2012

In the longway tunnel and underground traffic road, the structure of transverse ventilation system is constructed by the airpit slab. In this study, the full scale specimens of the PSC airpit slab that attached fire resistance panel are performed the static and dynamic loading tests for evaluation of bending capacity. The first of all, it confirmed the evaluations about the fundamental efficiency of the fire resistance panel and PSC slab by the 3-point bending test and pull-off test. The tests are performed for evaluation of the bending resistance under ultimate static load and the bonded capacity under dynamic fatigue load. A fatigue test is performed for an investigation of the effect on wind pressure that is developed by transit of traffic. The damage or debonding on surface between fire resistance panel and PSC slab was not developed in dynamic fatigue load test, also the behavior of the specimens is very stable and the debonding of the fire resistance panel attached at the bottom surface of PSC slab was not developed in static load test, too. Therefore, the crack or debonding of the fire resistance panel will be not developed by external loads during the construction or completion of the precast fire resistance system.