• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.167-174
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• 2003

This paper presented the results of cyclic loading tests of 7 full-scale beams to column subassemblages with improved connection detail i.e., fillets of the stiffening plates at the column corners and ends of the stiffener-to-beam flange weld. Major findings from the test results were: (1) Fillets reduced the stress concentrations that may cause early brittle fractures and considerably improved the cyclic performance compared to the detail without fillets. (2) As the width of the stiffening plate increased, the stiffness and peak strength increased and energy dissipation capacity decreased. (3) While all specimens failed by a fracture, they could develop a total rotation of 0.04 radian required for special moment resisting frames.

• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.511-522
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• 2014

In this study, an innovative steel stair system is presented which enables rapid erection and high quality control in both residential and office building construction. This system features two lightweight steel stringers of box shape, bolted connections easy to absorb construction tolerance, and stair steps movable transversely (or sliding steps) such that the work space needed for concrete stairway wall could be easily provided. In this type of stairway system, other than providing robust connecting details, ensuring vibration performance is especially important since this system may be vibration-sensitive due to lightweight nature and/or probable low damping. To tackle these issues, a series of full-scale mock-up tests were conducted by using box-shape stringer members with or without concrete-fill. The connection system was shown to be sufficiently stiff and strong, or it remained elastic even under the 160% of service load level. Among the seven stringer alternatives, five exhibited satisfactory vibration performance according to the related North American and European acceptance criteria.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.222-227
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• 2001

Full scale construction tests of CFT(concrete filled steel tube) column to solve construction problem and to confirm quality were performed in apartment site. To improve construction efficiency, the tests has been accomplished two stages after the tests for material mixing design had been completed. In the first stage, the experimental variables were the placing methods, existence of guiding pipe, placing velocity and drop height and the height of specimen were $3.6{\cal}m$. In the second stage, Filling steel tube of 9.6m height with concrete was performed by two ways, that is, the pump-up method and the dropping method. The filled condition of the concrete and concrete strength distribution according to the column height were checked and the quality of the CFT column was confirmed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.21-25
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• 2004

The column for Steel Framed Reinforced Concrete Structure (SFRCS) and the column for Reinforced Concrete Structure (RCS) could be the most common building structure. The increasing of the need for massive space hasaffected the size of building components for supporting the massive structure. However, the changing of components size makes inefficient space of building. Hence, to meet the need for acquiring efficient space comparing the budget and cost the new structure method, Concrete Filled Tube Steel (CFT), was developed. CFT is the structure for which steel tube instead of other materials such as wood for holding concrete is used. The most benefit of this one is to help in reducing the size of the building components and local buckling because of tube steel holding concrete. For this reason, this research will examine the probability of applying CFT on construction sites by using the concrete (800kgf/$\textrm{cm}^2$) especially for CFT through the data from the real size mock-up.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.149-158
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• 2006

The reduced beam section (RBS) steel moment connection has performed well in past numerous tests. However there still remain several design issues that should be further examined. One such issue on RBS connection performance is the panel zone strength. Although a significant amount of test data are available, a specific recommendation for a desirable range of panel zone strength versus beam strength has yet to be proposed. In this paper, the effects of panel zone strength on the cyclic performance of RBS connection are investigated based on the available test database from comprehensive independent testing programs. A criterion for a balanced panel zone strength that assures sufficient plastic rotation capacity while reducing the amount of beam buckling is proposed. Numerical studies to supplement the test results are then presented based on the validated finite element analysis. Satisfactory numerical simulation achieved in this study also indicates that numerical analysis based on quality finite element modeling can supplement or replace, at least in part, the costly full-scale cyclic testing of steel moment connections.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.629-639
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• 1998

This paper summarizes the results of full-scale cyclic seismic performance tests on three column-tree type steel moment connections. Each test specimen consisted of a $H-600{\times}200$ beam and a $H-400{\times}400$ column of SS41 (SS400). Key parameter included was column PZ (panel zone) strength relative to beam strength. The seismic performance of specimen with stronger PZ tended to be inferior. Total plastic rotations available in the specimens ranged from 1.8 to 3.0 (% rad). The limited test results in this study seem to support the speculation that permitting PZ yielding shall be more beneficial to enhancing total plastic rotation capacity of the moment connection. Beam flange fracture across the heat affected zone and divot-type pullout of the column flange were observed in the tests. A conceptual mechanical model consistent with observed test results was also sought.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.279-283
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• 2010

본 연구에서는 화재시 대규모 피해가 우려되는 승용차 밀집 공간을 가정하여 인접한 승용차로의 화재 전파 특성을 파악하기 위한 실물화재 실험을 실시하였다. 실험은 인접한 두 대의 승용차중 한 대의 차량에 화재를 발생시켜 화재가 성장되고 전파되는 과정을 분석하였으며, 산소소모율법을 적용한 발열량 측정이 동시에 이루어 졌다. 측정 결과 최대 열방출율은 약 9MW로 측정되어 선행된 승용차 한 대의 측정 발열량보다 약 2.5배이상 높은 범위의 값으로 평가되었다. 특히, 인접된 승용차로의 전파는 화재 발생후 약 3분 30초 경과후 창문으로 출화된 화염에 의하여 옆 차량에 화재가 전파되기 시작하였으며, 15분 경과후 완전히 화재가 전이되어 발달되었다. 따라서, 밀폐된 주차장에서의 화재시 발생초기에 가연 공간에서 화재가 진화가 이루어지지 않으면 약 3분 내에 다른 차량으로의 화재 전파가 우려 되며, 이후 급격한 피해를 줄 수 있는 상태로 화재가 성장하기 때문에 신속한 초기 대응이 필요함을 확인하였다. 이러한 실물화재실험에서 얻어낸 결과는 향후 여러 수치해석의 입력 조건으로 활용이 가능할 것이며, 화재 안전 설비 계획에 기본 자료로서 이용될 수 있을 것으로 기대된다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.4
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• pp.321-328
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• 2010

The study performed an actual fire experiment in order to propose the heat release rate of automobile that is the most basic architectural element for the fire safety design in a tunnel, whose importance has been recognized as the underground traffic tunnels are planned in Korean metropolitan cities. The heat release rate of a van is measured by the large scale calorimeter, in which the law of oxygen consumption is applied, and the fire expansion characteristics in a tunnel by placing two passenger cars nearby one another in the tunnel. As the results, the heat release rate of the van was revealed to be 5.9 MW, and carbon monoxide was emitted 482 ppm at a maximum. In case of two passenger car experiment for the fire expansion characteristics, the adjacent car was ignited about 3 minutes 30 seconds after the fire occurrence, and the complete fire was developed after 15 minutes. The maximum heat release was 9 MW. The results from the actual fire experiment can be an important input data for future quantitative analysis as well as an element applicable to a tunnel disaster preventive equipment design.

• Journal of Korean Society of Steel Construction
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• v.14 no.4
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• pp.557-566
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• 2002

This paper summarized the results of a full-scale cyclic seismic testing on four reduced beam section (RBS) steel moment connections. Specifically, these tests addressed a bolted web versus a welded web connection and strong versus medium panel zone (PZ) strength as key test variables. Specimens with medium PZ strength were designed to promote balanced energy dissipation from both PZ and RBS regions, in order to reduce the requirement for expensive doubler plates. Both strong and medium PZ specimens with welded web connection were able to provide sufficient connection rotation capacity required of special moment-resisting frames. On the other hand, specimens with bolted web connection performed poorly due to premature brittle fracture of the beam flange at the weld access hole. Unlike the case of web-welded specimens, specimens with cheaper bolted web connection could not transfer the actual plastic moment of the original (or unreduced) beam section to the column. No fracture occurred within the beam groove welds of any connection in this testing program. If fracture within the beam flange groove weld is avoided by using quality welding procedure as in this study, the fracture issue tends to move into the beam flange base metal at the weld access hole. Supporting analytical study was also conducted in order to understand the observed base metal fracture from the engineering mechanics perspective.

• Fire Science and Engineering
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• v.25 no.3
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• pp.51-56
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• 2011

The full-scale experiments are carried out to investigate the fire suppression characteristics of water-based fire fighting systems in a road tunnel. Applied systems are the low-pressure water spray system at 3.5 bar and the high-pressure water mist system at 60 bar. The water flow rate of the high-pressure system is one sixth only of the water spray system. A passenger car and a heptane fuel pan with area of $1.4m^2$ are used as fire sources. A blower system is installed at the tunnel exit to realize the longitudinal ventilation conditions (0.9~3.8 m/s) in the tunnel. Temperatures from the fire source to the down-stream direction are measured by K-type thermocouple trees. The experimental results show that the cooling effect of the high pressure water mist system in the test conditions were equivalent to that of the low pressure water spray system for B-class fire.