• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.124-127
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• 2004

This study is to investigate the bond characteristics of glass fiber reinforced polymer(GFRP) reinforcing bars in concrete by pullout test experimentally. Three different types of GFRP bars with different surface deformations were considered in this study. Also, standard deformed steel reinforcing bar with or without epoxy-coating were included for the comparisons of bond strength. All test procedures including specimens preparation, test apparatus and measuring devices were made according to the recommendation of CSA(Canadian Standards Association) Standard S806-02. From the test results, it was found that small surface indentations contributed to increase the bond strength of GFRP bar significantly. Based on the limited test results till now, the bond strength of GFRP bar with sand-coated deformation commercially available in foreign market is around $80\%$ of that of steel deformed bars.

• Journal of Chest Surgery
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• v.49 no.6
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• pp.481-484
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• 2016

A 53-year-old man arrived at the trauma center with a steel bar penetrating from the epigastrium to the right scapula. He was hypotensive and hypoxic, and immediate resuscitation and basic evaluation were performed. An emergency operation was performed due to an unstable hemodynamic state. Multiple injuries were confirmed in the right lower lobe, posterior chest wall, diaphragm, and liver lateral segment. Right lower lobectomy and liver lateral sectionectomy were performed following removal of the bar. The patient recovered without additional hemorrhage after the surgery, and was transferred to a rehabilitation institution with periodic follow-up.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.282-288
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• 2002

A new on-line bar joining technology employing the concept of a solid-state joining has been developed for the endless rolling by POSCO, RIST and MHMM Inc.. In the process, the bars are partially descaled, partially overlapped, joined by shearing action and crops are finally removed. The feasibility of the developed process was evaluated in this study in terms of microstructures and mechanical properties of joints, and the response of the joint to rolling.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.323-326
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• 2005

Uniaxial tension test of Glass Fiber Reinforced Polymer (GFRP) bar reinforced concrete prisms was performed. The objective was to investigate the adequate cover thickness of the GFRP rebars. The tension stiffening effect of GFRP bar reinforced concrete was also studied. The test variables included rebar types (conventional steel rebar and two different GFRP rebars) and cover thicknesses (five different cover thicknesses ranging between 1-3db). Normal strength concrete was used. Cracking patterns on concrete surface and cracking loads were careful1y observed during the direct tensile test. The test results indicated that the adequate cover thickness of the GFRP rebars may even be larger than that of the steel rebars and that the cover thickness of 2db commonly specified for the GFRP rebars may not be large enough. The tension stiffening effect of the GFRP rebars was also quantified and documented from the test results.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.321-324
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• 2006

An experimental study on the bond strength of wall-slab joint in SC(steel plate-concrete) structure was performed. Six-full scale specimens were tested. Specimens were constructed with key variables, such as, development length, location of the bar and quantity of the shear bar. The experimental results, show that as the development length and quantity of the shear bar increase, the bond strength increases. As the bars is located on the inside the stud bolt, the bond performance was highly increased compared to the bars located out of plane of the stud bolts.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.3
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• pp.19-25
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• 2019

The purpose of this study was to evaluate bending performance of concrete filled soldier pile for temporary retaining wall. Structural performance tests were conducted on total number of four specimens. Each specimen had a unique characteristics with combination of the following variables, existence of reinforcing bar and locations of reinforcing steel plates. The results of this study were as follows; concrete filled steel tubes with being reinforced bar and flange rather than non-bar showed better performance. Higher yield, tensile strength and sufficient plastic strain were archived and maximum moment observed in experiments exceeded theoretical maximum moment in both allowable stress design and limit state design at all specimens.

• Archives of Metallurgy and Materials
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• v.65 no.4
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• pp.1245-1248
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• 2020

Section steels produced by welding are essential parts for shipbuilding and offshore plant production. T-type and H-type section steels are produced by handwork for secondary processing, which is a generally difficult and tedious activity. Therefore, automatic welding, with sound welding properties and a high-speed process, is necessary to meet the production demands. Welding conditions can be optimized by controlling various parameters to obtain suitable and highly reliable microstructural properties. In this study, the heat affected zone and weld defects of fillet-welded Angle and T-bar parts were investigated in terms of their microstructural, macrostructural, and mechanical properties to ensure the soundness of AH36 section steel parts joined by continuous welds.

• Journal of Korean Society of Steel Construction
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• v.15 no.5 s.66
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• pp.571-578
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• 2003

An effective seismic retrofit scheme for inverted V braced (or chevron type) steel frames was proposed by studying the redistribution of forces in the post-buckling range. The steel frames with chevron bracing are highly prone to soft story response once the compression brace buckles under earthquake loading. This paper shows that the seismic performance of such frames could be significantly improved by supplying tie bars to redistribute the inelastic deformation demand over the height of the building. A practical design method of the retrofit tie bars was also proposed by considering the sequence of buckling occurrence.

• Korean Journal of Metals and Materials
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• v.50 no.1
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• pp.13-22
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• 2012

Forged and flat-bar rolled STD11 tool steel shows anisotropic dimensional change during heat treatment. The dimensional change in the rolling direction is larger than that in the transverse direction. The cause of the anisotropic dimensional change is that the steel is anisotropic in composition, microstructure and other properties. The decrease of anisotropic distortion in tool steel is important for making better precision cold working dies. In this study, the effect of ingot weight and hot rolling reduction ratio on the anisotropic dimensional change of STD11 during heat treatment has been studied. Dimensional change was evaluated by simulating a real heat treatment process, including gas quenching and tempering. Experimental results showed that all the rolled flat-bar products had anisotropic distortion to some degree, but the anisotropic distortion was reduced as hot rolling ratio increased. Ingot weight had a little effect on anisotropic distortion. Microstructural observation showed that the anisotropic dimensional change of STD11 tool steel was closely related to the amount, shape and distribution of coarse carbides.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.171-180
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• 2019

In Korea, the seismic design of non-structural elements was interested by Earthquake of the 2016 Gyeong-ju and 2017 Po-hang. Among the non-structural elements, the ceiling system with steel panel used in Po-hang station showed failure examples of non-seismic design ceiling. In this study, the seismic performance of suspended ceiling with steel-panel, such as those used in Po-hang Station, was evaluated by shaking table tests. The shaking table tests were performed in accordance with the ICC-ES AC156 standard with floor acceleration being applied horizontally in one direction using a $3.3{\times}3.3m^2$ frame. The ceiling system consists of steel-panels, carrying channels, main and cross T-bars, and anti-falling clips. The anti-falling clip prevents the steel panel falling completely. The shaking table test confirmed that the damage at the previous stage had a direct impact on the damage state at the next stage. Through the shaking table test, the damage state of the T-bar type steel-panel suspended ceiling system was defined.