• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.6
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• pp.901-907
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• 2013

The development of high-rise firefighting vehicles warrants thorough structural analysis for ensuring vehicle stability. A few structural analyses were carried out using CAD data, material properties, load conditions, and boundary conditions for evaluating the structural stability of an overloaded multi-aerial platform for firefighting and rescue. Structural analysis was performed with an analytical model consisting of a turntable, six booms, two jib booms, and a basket structure. This model was operated in eight modes. All simulation was performed using NASTRAN, a commercial code. As a result, we confirm that the position of local stress exceeds that of the yield strength. Therefore, stress concentration relaxation is possible by introducing reinforcing boom structures, changing the shape, or imparting a larger moment of inertia to the booms' cross sections.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.16 no.1
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• pp.45-54
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• 2012

• Advances in concrete construction
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• v.6 no.2
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• pp.177-197
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• 2018

This paper presents a case study about the damages on the structural elements of a cast in place reinforced concrete (RC) building after a big fire which was able to be controlled after six hours. The fire broke off at the $2^{nd}$ basement floor of the building, which has five basements, one ground, and two normal floors. As a result of intensely stocked ignitable materials, it spread out to the all of the upstairs. In visual inspection, most of the typical fire damages were observed (such as spalling, net-like cracks, crumbled plasters, bared or visible reinforcement). Also, failures of the $2^{nd}$ basement columns were encountered. It has been concluded that the severity failures of the columns at the $2^{nd}$ basement caused utterly deformation of the building, which is responsible for the massive damages on the beam-column connections. All of the observed damages were categorized related to the types and presented separated regarding the floors. Besides to the visual inspection, the numerical analysis was run to verify the observed damaged on the building for columns, beams, and the connection regions. It is concluded from the study that several parameters such as duration of the fire, level of the temperature influence on the damages to the RC building. Also, it is highlighted by the study that if the damaged building is considered on the overall structural system, it is not able to satisfy the minimum service requirements neither gravity loads nor earthquake conditions.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.461-470
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• 2009

A column resisting axial load and seismic load is one of the main members in a structural system. The heated column by event of a fire can lose its strength and it may damage its structural system or cause the collapse of the entire structural system. In this study, the fire resistance capacity of internally confined hollow concrete filled tube (ICH CFT) column was investigated. In an ICH CFT column, the yield strength of the external tube is important as a concrete filled tube (CFT) column because the external tube confines the filled concrete and the strength of the column depends on the confined effect. A study was performed by finite element analyses considering the confined effect and material nonlinearity as the temperature changes by the fire. The hollow ratio, the thickness of the external tube, and the strength of concrete were selected as the parameters for the analyses. The analyses were performed by using a commercial FEA program (ABAQUS) and nonlinear concrete model program. The analysis results showed that the hollow ratio and the strength of concrete mainly affect the fire resisting capacity of an ICH CFT column.

• Structural Engineering and Mechanics
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• v.50 no.6
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• pp.755-772
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• 2014

A simplistic approach towards evaluation of complete load deflection response of Reinforced Concrete (RC) flexural members under post fire (residual) scenario is presented in this paper. The cross-section of the RC flexural member is divided into a number of sectors. Thermal analysis is performed to determine the temperature distribution across the section, for given fire duration. Temperature-dependent stress-strain curves for concrete and steel are then utilized to perform a moment-curvature analysis. The moment-curvature relationships are obtained for beams exposed to different fire durations. These are then utilized to obtain the load-deflection plots following pushover analysis. Moreover one of the important issues of modeling the initial stiffness giving due consideration to stiffness degradation due to material degradation and thermal cracking has also been addressed in a rational manner. The approach is straightforward and can be easily programmed in spreadsheets. The presented approach has been validated against the experiments, available in literature, on RC beam subjected to different fire durations viz. 1hr, 1.5hrs and 2hrs. Complete load-deflection curves have been obtained and compared with experimentally reported counterparts. The results also show a good match with the results obtained using more complicated approaches such as those involving Finite element (FE) modeling and conducting a transient thermal stress analysis. Further evaluation of the beams during fire (at elevated temperatures) was performed and a comparison of the mechanical behavior of RC beams under post fire and during fire scenarios is made. Detailed formulations, assumptions and step by step approach are reported in the paper. Due to the simplicity and ease of implementation, this approach can be used for evaluation of global performance of fire affected structures.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.64-72
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• 2020

In this study, a stability analysis was conducted through finite element analysis (FEA) of a simplified model of a fire ladder truck by changing the ascending angle, turning angle, and boundary conditions between the outrigger and the ground. The results of the analysis showed that decreasing the angle of the ladder car increases the moment due to the ladder weight, decreasing the safety factor despite being under the same load conditions. In the case of a rotating radius, the stability was found to vary depending on the boundary conditions. A comparative analysis in the future with these results and the experimental values from the actual fire ladder truck may determine the most appropriate boundary conditions based on the analysis program. It is expected to predict the risk of damage and rollover by assessing the stability of aerial ladder vehicles under different conditions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.4
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• pp.1-8
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• 2012

The aim of this study is to evaluate fire-induced damage for shield tunnel linings. Full-scale fire test was conducted to evaluate fire-induced damage. Residual compressive strength was measured on the core samples of shield tunnel lining subjected to high temperatures. Heating temperature was predicted by XRD and TG analysis. As a result, Strength degradation of concrete with temperatures can be evaluated by residual compressive strength of core samples. In addition, residual compressive strength can be estimated by previous studies if heating temperature is exactly predicted. It is possible that heating temperature is predicted by XRD and TG analysis at $450^{\circ}C$. For more accurate prediction of heating temperature it should be performed both instrumental analysis and analytical methods with temperatures ranging from $400{\sim}600^{\circ}C$.

• Fire Science and Engineering
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• v.22 no.3
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• pp.239-245
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• 2008

In this study, we researched about characteristics of many kinds of tank cars for carrying hazard materials and performed structural strength evaluation using finite element analysis for tank of asphalt tank car to suggest the efficient analysis method that can develop accuracy regarding to characteristics of tank cars. For this, we analyzed the asphalt tank refer to JIS E 7102 (Design Method for Tanks of Tank Cars). As results, we could show that the maximum stress is applied at the area supported by saddle and the maximum stress is under a criterion suggested from JIS E 7102. Therefore we verified that this asphalt tank car had enough structural strength.

• Computers and Concrete
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• v.21 no.6
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• pp.637-647
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• 2018

Numerical approach using finite element method has been used to evaluate the behaviour of reinforced concrete frame structure subjected to fire. The structure is previously designed in accordance with Eurocode standards for the design of structures for earthquake resistance, for the ductility class M. Thermal and structural response are obtained using a commercially available software ANSYS. Temperature-dependent nonlinear thermal and mechanical properties are adopted according to Eurocode standards, with the application of constitutive model for the triaxial behaviour of concrete with a smeared crack approach. Discrete modelling of concrete and reinforcement has enabled monitoring of the behaviour at a global, as well as at a local level, providing information on the level of damage occurring during fire. Critical regions in frame structures are identified and assessed, based on temperatures, displacements, variations of internal forces magnitudes and achieved plastic deformations of main reinforcement bars. Parametric analyses are conducted for different fire scenarios and different types of concrete aggregate to determine their effect on global deformations of frame structures. According to analyses results, the three-dimensional finite element model can be used to evaluate the insulation and mechanical resistance criteria of reinforced concrete frame structures subjected to nominal fire curves.

• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.6-12
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• 1993

Now it is reported that there are many companies and factories which confront to the problem of false alarm in Automatic Fire Detecting System (AFDS). Though an AFDS is a high-priced and very important device in detecting a fire. the problem degrades the reliability and utility, eventually faith. of the system. This is a research concerned about the problem of false alarm of fire detectors in an AFDS. Structure of detectors was modeled up as a general K out-of n system. and reliability characteristics including false alarm rate and missed alarm rate, are derived from it. For decision of an optimal structure of detectors. preliminary analysis on various criteria is accomplished. It is concluded that appropriate modification of a detector with plural sensors may increase the system reliability and decrease the false alarm rate.