• 자원리싸이클링
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• 제9권6호
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• pp.53-57
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• 2000

본고는 스틸 폐캔을 재생 스틸로 용해시 금속 회수율을 높이기 위하여 스틸 폐캔을 예비처리하는 방법과 연속적으로 처리하기위한 자동화 장치에 관한 국내 개발 기술사례이다. 본 개발기술은 스틸 폐캔 더미의 와해, 이물질제거, 알루미늄 폐캔 분리, 도료와 락카제거 등의 예비처리 공정들과, 락카제거된 스틸 폐캔들을 다시 압착하여 일정한 크기의 더미로 제조하는 공정으로 구성되어 있으며, 스틸 폐캔 용해시에 적합한 형태로 처리하는 것을 최종목표로 하였다. 또한, 락카 제거시에 부산물로 발생된 철분과 알루미늄 분말 혼합물을 자력선별기를 사용하여 분리 회수하였다. 이와 같은 일련의 처리를 통해서 제강공장에서 재활용하기에 적합한 형태로 스틸 폐캔을 처리할 수 있으며, 전 공정을 자동화시킴으로써 대량의 스틸 폐캔을 효과적으로 처리할 수 있다.

• Structural Engineering and Mechanics
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• 제77권6호
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• pp.705-720
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• 2021

Reinforced concrete (RC) columns are the primary type of vertical support used in building structures that sustain vertical loads. However, their strength may be insufficient due to fire, earthquake or volatile environments. The load demand may be increased due to new functional usages of the structure. The deformability of concrete columns can be greatly reduced under high axial load conditions. In response, a novel steel encasement that distinguishes from the traditional steel jacketing that is assembled by welding or bolt is developed. This novel strengthening method features easy installation and quick strengthening because direct fastening is used to connect the four steel plates surrounding the column. This new connection method is usually used to quickly and stably connect two steel components by driving high strength fastener into the steel components. The connections together with the steel plates behave like transverse reinforcement, which can provide passive confinement to the concrete. The confined column along with the steel plates resist the axial load. By this way, the axial load capacity and deformability of the column can be enhanced. Eight columns are tested to examine the reliability and effectiveness of the proposed method. The effects of the vertical spacing between adjacent connections, thickness of the steel plate and number of fasteners in each connection are studied to identify the critical parameters which affect the load bearing performance and deformation behavior. Lastly, a theoretical model is proposed for predicting the axial load capacity of the strengthened RC columns.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1149-1156
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• 2011

A rockbolt is one of the most important reinforcement of on-site soil, as with the shotcrete and steel rib. The rockbolt by setting within the tunnel can prevent the deformation of the ground profile; furthermore it improves the structural behavior of soil and rock. In general, the rockbolt is mainly used with reinforced steel. However, steel pipe or the materials with the same strength can be used depending on the soil conditions, ground water outflow condition, and the surrounding of applying location. In Korea, most tunnel construction sites have used cement mortar or resin for steel reinforcement on the rock. Due to the ground water outflow in the construction site, the usability of steel reinforcement is poor and it requires curing time especially after installation. To improve exist above problems, this study introduces the development of a swelled steel pipe rockbolt, as well as presents the field testing and performance results.

• 자원리싸이클링
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• 제23권5호
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• pp.62-67
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• 2014

금속캔은 리싸이클링이 용이한 포장용기로서 금속 폐캔을 효율적으로 리싸이클링하는 것은 자원재활용 측면에서 매우 중요한 일이다. 금속캔은 EPR 해당 품목으로서 재질에 따라 스틸캔과 알루미늄캔으로 분류되는데, 국내의 경우에는 스틸캔이 80% 가량을 차지하고 있다. 본 고에서는 2008년부터 최근 5년간 금속 폐캔 발생량과 재활용 현황 및 처리방법을 알루미늄캔과 스틸캔별로 조사하였다. 2012년 금속캔의 재활용을 중량비로 살펴보면 스틸캔이 80.8%, 알루미늄캔은 81.8%였으며 금속캔 전체로는 81.1%의 재활용율을 기록하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.485-488
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• 2004

Steel encased composite columns have been used for buildings and piers of bridges. Since column section for pier is relatively larger than that of building columns, economical steel ratio need to be investigated for the required performance. Composite action between concrete and embedded steel sections can be obtained by bonding and friction. However, the behavior. of the column depends on the load introduction mechanism. Compression can be applied to concrete section, steel section and composite section. In this paper, experiments on shear strength of the steel encased composite column were performed to study the effect of confinement by transverse reinforcements, mechanical interlock by holes, and shear connectors. Shear strength obtained from the tests showed considerably higher than the design value. Confinement, mechanical interlock and stud connectors increased the shear strength and these values can be used effectively to obtain composite action of SRC columns.

• Earthquakes and Structures
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• 제7권3호
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• pp.333-347
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• 2014

Multi-scale model can take both computational efficiency and accuracy into consideration when it is used to conduct elasto-plastic seismic response analysis for complex steel bridges. This paper proposed a method based on pushover analysis of member sharing the same section pattern to verify the accuracy of multi-scale model. A deck-through type steel arch bridge with a span length of 200m was employed for seismic response analysis using multi-scale model and fiber model respectively, the validity and necessity of elasto-plastic seismic analysis for steel bridge by multi-scale model was then verified. The results show that the convergence of load-displacement curves obtained from pushover analysis for members having the same section pattern can be used as a proof of the accuracy of multi-scale model. It is noted that the computational precision of multi-scale model can be guaranteed when length of shell element segment is 1.40 times longer than the width of section where was in compression status. Fiber model can only be used for the predictions of the global deformations and the approximate positions of plastic areas on steel structures. However, it cannot give exact prediction on the distribution of plastic areas and the degree of the plasticity.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.23-28
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• 2001

Since the steel fiber used in concrete to improve shear and ductility capacity, a number of laboratory tests have been studied to define shear strengthening effect according steel fiber contents in concrete. This study investigates shear strengthening effect of steel fiber in RC columns according to compression strength of concrete. From the structural performance test, following conclusions can be made; the maximum enhancement of shear strengthening effect can be achieved at about 1.0 %~l.5 % of steel fiber contents in comparison with shear capacity ratio, and ductility capacity slightly improved as steel fiber contents increased.

• 자원리싸이클링
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• 제17권6호
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• pp.89-93
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• 2008

금속캔은 리싸이클링이 용이한 포장용기로서 자원이 부족한 우리로서는 금속 폐캔을 효율적으로 리싸이클링하는 것은 자원재활용 측면에서 매우 중요한 일이다. 금속캔은 재질에 따라 스틸캔과 알루미늄캔으로 분류되는데, 국내의 경우에는 스틸캔이 80% 이상을 차지하고 있다. 본 고에서는 최근 몇 년 간의 금속 캔 생산과 발생된 폐캔의 재활용 현황과 처리방법을 알루미늄캔과 스틸캔별로 조사하였다. 2007년 스틸캔의 경우에는 중량비로 재활용율이 75.6%였고, 알루미늄캔은 74%로서 금속캔 전체로는 75.4%의 재활용율을 기록하였다.

• Steel and Composite Structures
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• 제25권1호
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• pp.45-55
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• 2017

Stainless steel exhibits high ductility and strain hardening capacity in comparison with carbon steel widely used in constructions. To analyze the particular behaviour of stainless steel cover-plate joints, an experimental study was conducted. It showed large ductility and complex failure modes of the joints. A non-linear finite element model was developed to predict the main parameters influencing the behaviour of these joints. The results of this deterministic model allow us to built a meta-model by using the quadratic response surface method, in order to allow for efficient reliability analysis. This analysis is then applied to the assessment of design formulae in the currently used codes of practice. The reliability analysis has shown that the stainless steel joint design according to Eurocodes leads to much lower failure probabilities than the Eurocodes target reliability for carbon steel, which incites revising the resisting model evaluation and consequently reducing stainless steel joint costs. This approach can be used as a basis to evaluate a wide range of steel joints involving complex failure modes, particularly bearing failure.

• 대한건축학회논문집:구조계
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• 제34권7호
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• pp.3-10
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• 2018

Steel fiber reinforced concrete can improve the resistance to cracking by adding steel fibers when mixing concrete. It can reduce the temperature and shrinkage cracks, and its flexural performance can be improved by increasing the effective moment of inertia. In this study, the deck-plate was used to replace the concrete form and reinforcing bars, and the steel fiber reinforced concrete was used to control the shrinkage and temperature cracks, and improve the flexural performance of the slab. Total 9 slab specimens were tested for analyzing the structural performance and serviceability. As a results, flexural capacity of the slab with deck-plate was evaluated to be superior to that of the normal reinforced concrete slab specimens with the same tensile reinforcement. The steel fiber reinforced concrete was found to have about 8% flexural capacity increase depending on the steel fiber content $15.7kg/m^3$. Also, in terms of flexural stiffness, the specimens using steel fiber reinforced concrete for the same parameters were evaluated to have a stiffness increase of about 30% compared with the case of using ordinary concrete. Especially, it was found that the stiffness of the test results was significantly higher than the analytical result because the increase of the tensile strength of the steel fiber reinforced concrete is not reflected in the current structural code.