• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.109-110
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• 2020

In the event of a fire, fire engines usually arrive within 15 minutes and become a fire suppressor. In this paper, an analytical model was established to evaluate the salt damage resistance of concrete according to fire suppression time, and the concentration of salt inside the concrete after fire was measured and the time to reach the critical concentration was assessed by how short.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.84-96
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• 2022

In the worst case, a temporary ignition source (also known as transient combustibles) between two electrical panels can damage both panels. Mitigation strategies for electrical panel fires were previously developed using fire modeling and risk analysis. However, since they do not comply with deterministic fire protection requirements, it is necessary to analyze the boundary values at which combustibles may damage targets depending on various factors. In the present study, a sensitivity analysis of input variables related to the damage threshold of two electrical panels was performed for dimensionless geometry using a Fire Dynamics Simulator (FDS). A new methodology using a damage evaluation map was developed to assess the damage of the electrical panel. The input variables were the distance between the electrical panels, the vertical height of the fuel, the size of the fire, the wind speed and the wind direction. The heat flux was determined to increase as the vertical distance between the fuel and the panel decreased, and the largest heat flux was predicted when the vertical separation distance divided by one half flame length was 0.3-0.5. As the distance between the panels increases, the heat flux decreases according to the power law, and damage can be avoided when the distance between the fuel and the panel is twice the length of the panel. When the wind direction is east and south, to avoid damage to the electrical panel the distance must be increased by 1.5 times compared to no wind. The present scale model can be applied to any configuration where combustibles are located between two electrical panels, and can provide useful guidance for the design of redundant electrical panels.

• Journal of the Korea Safety Management & Science
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• v.23 no.1
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• pp.57-64
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• 2021

Recently, advanced countries assessment the risk of fire to prevent large-scale damage to high-rise buildings, In addition, performance-Based design, which is a fire risk assessment, is being conducted in Korea to prevent massive damage to high-rise buildings. However, unlike advanced countries, fire risk assessment in Korea is subject to fire risk assessment only for objects subject to consent from fire-fighting facilities such as building permits, When building engineers and fire-fighting engineers assessment the risk of fire, It has always been discussed because the results vary depending on which part of the evaluation is focused between economic feasibility and safety. Therefore, in this study, we would like to propose a fire risk assessment process suitable for domestic conditions by comparing the process of performance-based design, which is a domestic fire risk assessment, and the process of Iso/TC 16732 which is an overseas fire risk assessment.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.80-87
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• 2013

Heat transfer analysis and thermal stress analysis for the concrete bridge was performed in order to investigate the damage of the concrete bridge by the fire of the vehicle. Changes in material properties, such as thermal conductivity, specific heat, density, elasticity, caused by temperature rise were considered. Heat transfer analysis and thermal stress analysis were performed according to the various location of the fire by ABAQUS. From the comparison of the numerical results, the degree of structural damage for the concrete bridge was investigated and considerations for the design of a concrete bridge against fire were identified.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.485-488
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• 2008

Fire intensity in tunnel fire is very severe, which might cause the spalling on the surface of shotcrete and concrete lining exposed to the heat as well as rapidly-reducing stress due to heat transfer by steel material such as anchor embedded in tunnel which plays the critical role in securing the stability of the tunnel. In this study, a fire test to identity the heat intensity(Modifired Hydrocarbon Curve) and the fire resistance of steel materials embedded as parameters, was carried out. And the evaluation to identify the thermal damage, which was based on critical temperature range for thermal damage of steel materials determined according to the road tunnel fire resistance standard established by ITA(International Tunneling Association).

• Journal of the Korean Society of Safety
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• v.12 no.2
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• pp.140-145
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• 1997

The main purpose of this study is to establish the reliable method for evaluating fire damage of reinforced concrete building, by using the rational procedure, and to develope the rehabilitation methods of fire damaged concrete structures. Especially, this proposed evaluation method is applied to the fire damaged concrete buildings of domestic, and the rehabilitation methods on the basis of these applied results are proposed and those example are shown. The proposed rational evaluation method for fire damaged concrete building proceeds is estimating the reduction of the mechanical properties of concrete of fire damaged structural members in comparison with the experimental results which are obtained from the compression tests of heated concrete specimens under various temperatures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.42-48
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• 2017

When concrete structures expose to fire, the structures were damaged accompanied with degradation of material properties of concrete. In order to determine the reuse of fire-damaged concrete structures, it is needed a careful determination considering conditions of fire damage, such as exposure temperature and exposure time, and also potential to restore fire damage. This study investigates on the evaluation of residual material properties of fire-damaged concrete under different post-fire curing regimes. An experimental study was performed on concrete samples to measure the dynamic elastic modulus by the impact resonance vibration method. Upon the experimental results, the evidence of restoration of material properties was confirmed on specific post-fire curing regimes, higher humidity conditions. Additionally, a correlation analysis was performed on the dynamic elastic modulus with the tensile strength for identifying the effects of post-fire curing regimes on both material properties of fire-damaged concrete.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.171-177
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• 2005

Fire in underground space may induce severe structural damage as well as heavy casualties. To protect underground structure and passengers from fire, it is very essential to characterize fire-induced damage on construction materials of underground structures. In this study, the high-temperature furnace was manufactured to evaluate fire-induced damage on underground structure materials. Especially, this study aimed at the evaluation of fire-induced damage on the shield TBM concrete segment. In the fire tests, furnace temperature was set to reach 1,200 degrees at five minutes after Ignition. The temperature of 1,200 degrees was kept during one hour, and the fire was extinguished after two hours elapsed. From the temperature measurement by thermocouples embedded in test specimens, the spatting was estimated to reach approximately 20 cm from the surface exposed to fire. After the fire tests, the alteration of physico-mechanical properties and microstructures of concrete segment was investigated from core specimens. The results showed that apart from spatting, the deterioration depth of the remaining concrete material amounted to approximately 10 cm from the spatting surface.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.221-226
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• 1994

A safety evaluation of cable tunnel, which is a concrete box structure with telecommunication facilities in it, exposed to fire is given. The immediate field observation was performed to find out any sign of sudden structural failure. In some region, where the fire intensity was heavy, the spalling of concrete cover in upper slab occurred. Next, more careful investigation was done with proper non-desturctive testing methods and structural analysis taking into account the changes in material properties due to fire. It seems that there is no severe damage on concrete, reinforcements and over all structural system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.283-292
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• 2013

The objective of this research is to evaluate of global and local damage for steel-concrete composite structures under highway bridge exposed to fire loading. To enhance the accuracy and efficiency of the numerical analysis, the proposed transient nonlinear thermal structure interaction(TSI) parallel fire analysis method is implemented in ANSYS. To validate the TSI parallel fire analysis method, a comparison is made with the standard fire test results. The proposed TSI parallel fire analysis method is applied to fire damage analysis and performance evaluation for Buchen highway bridge. The result of analysis, temperature of low flange and web are exceed the critical temperature. The deflection and deformation state show good agreement with the fire accident of buchen highway bridge.