• Steel and Composite Structures
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• 제21권1호
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• pp.73-91
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• 2016

The use of box columns has been increased due to the rigidity in rigid orthogonal moment resisting frames. On the other hand, the installation and welding of necessary horizontal continuity plates inside the columns are both labor-consuming and costly tasks. Accordingly, in this paper, a new beam-to-box column connection by trapezoidal external stiffeners and horizontal bar mats is presented to provide seismic parameters. The proposed connection consists of eight external stiffeners in the level of beam flanges and five horizontal bar mats in Concrete Filled Tube (CFT) columns. The new connection effectively alleviates the stress concentration and moves the plastic hinge away from the column face by horizontal external stiffeners. In addition, the result shows that proposed connection has provided the required strength and rigidity of connection, so that the increased strength, 8.08% and rigidity, 3.01% are compared to connection with internal continuity plates, also the results indicate that this connection can offer appropriate ductility and energy dissipation capacity for its potential application in moment resisting frames in seismic region. As a result, the proposed connection can be a good alternative for connection with continuity plates.

• 토지주택연구
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• 제2권1호
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• pp.61-68
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• 2011

본 연구는 벽식구조 아파트의 슬래브와 벽체를 철근격자망으로 배근할 경우 접합부의 구조성능을 검증하기 위해 수행되었다. 이를 위해 벽체와 연결된 불연속단의 캔틸레버형 슬래브 시험체를 사용하여 철근격자망 상부근의 정착길이와, 철근격자망의 정착부에 일반 구부림 철근을 사용하여 정착한 경우의 정착방법 및 길이를 변수로 실험을 수행하였다. 결과는 다음과 같다. (1) 슬래브-벽체 외부접합부의 철근망 시공에서 슬래브 철근망은 벽체의 철근 선까지 배근하고 이음길이를 확보한 별도의 철근을 $90^{\circ}$ 표준갈고리로 정착하는 경우, 정착길이와 단면적이 확보되면 강도 발현에 문제가 없는 것으로 나타났다. (2) 슬래브 철근망을 접합부에서 이음할 때 철근망의 철근을 벽체 속으로 매입하면 강도는 더욱 증가한다. 그러나 최고강도에 도달한 이후의 연성은 이음이 없는 것과 동일한 것으로 나타났다. (3) 슬래브-벽체 외부접합부에서 단부 모멘트에 대한 슬래브 하부 압축콘크리트의 파괴시 변형률은 일반 콘크리트 보와 비교할 때 훨씬 큰 것으로 나타났다. 이는 슬래브-벽체 접합부가 $90^{\circ}$를 이루고 있어 이에 따른 구속효과가 있기 때문인 것으로 판단된다.

• 보건교육건강증진학회지
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• 제22권4호
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• pp.203-213
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• 2005

Purpose: To assess the environmental hazards of falling accident in the homes of the elderly. Method: 222 homes of the elderly were assessed by the home environmental Checklist from May to July in 2003. Results: The mean score of home environmental hazards for fall were 13.19 with the highest score being 49, ranging from 4 to 24. The bathroom was the most hazardous place in the home, porch came next bedroom, kitchen, living room and stair followed them. The floor surface such as finishes and non-skid mats was the most hazardous interior factor in the home, using bathroom came next furniture and illumination followed them. The floor surface such as finishes and non-skid mats in the bathroom, kitchen, living room and porch, illumination of bedroom and stair were the most prevalent hazards in the home of interior. Of the 49 potential hazards, bathroom grab bar was the most prevalent one with 89.9%, and non-skid rugs in the porch, bathroom and kitchen, safety of dinner table, the threshold and furniture of porch, and illumination of bedroom were prevalent more than half of the home under assessing. Men, living in the separate house or villa with stairs were in more hazardous environments. Conclusion: To reduce the potential hazards of fall accident in the home, improving hazards relating to floor surface such as slip resistance surface and mats is important specially those of the separate house or villa with stairs.

• 한국환경복원기술학회지
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• 제6권4호
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• pp.62-73
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• 2003

The study was to apply a mat style reed planting method at confluence to improve plants growth conditions by relaxing disturbed topographical base due to water flow and was intended to review the effect to build up a vegetation strip by monitoring process after the construction. First off, We've attempted to construct reed mats on selected sites as confluences of Tan and Gaehwa stream and then examined and analyzed characteristics of soil and vegetation community. As the results of the examination, the soil texture was proven to be a mix of sand and loamy sand and be 6.3 ~ 7.0 soil pH. In addition, it contained 1.0 ~ 4.6% of organic matter, 0.04 ~ 0.22% of T-N and 27.8 ~ 41.2% of water content. For its vegetation structure, the Tan stream confluence was first actually a point bar without plants prior to the construction but 8 kinds of hygrophytes including Persicaria hydropiper and 9 kinds of terrestrial plants such as Potentilla supina, Artemisia annua, and Alopecurus aequalis var. amurensis. On the other hand, the Gaehwa stream confluence contained 6 kinds of hygrophytes such as Bidens frondosa and other 11 kinds of terrestrial plants prior to the construction while it produced 7 kinds of hygrophytes including Ranunculus ternatus as well as Phragmites australis and 9 kinds of terrestrial plants such as Potentilla supina after the construction. For the Phragmites australis, almost of them was weathered away in early days just after planting because of development period passed, but on May, six months later from planting, it was investigated that its length was approximated as 65 ~ 85cm with 75% coverage and that the number of it was 437 ~ 633/$m^2$. The study was shown that reed mats can improve environmental conditions of disturbed topographical base, enabling natural growth of various riparian vegetation including the introduced plant, reed. In the meantime, it was supposedly judged that to recover or build up a vegetarian strip, supplementary materials should be prepared to help produce and grow plants because it is not probable to expect river drift by water flow at confluence and that corrosion, burying or inundation owing to changes of water lever should be considered.

• 한국지반환경공학회 논문집
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• 제13권2호
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• pp.83-93
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• 2012

보강토옹벽은 1980년대 초반 국내에 도입된 이래로, 다양한 금속 혹은 토목섬유 보강재가 개발되어 현장에 적용되고 있으며, 특히, 국내에서는 지오그리드가 가장 많이 적용되고 있다. 이에 본 연구에서는 현재 국내에서 생산되고 있는 4가지 종류의 지오그리드에 대해 인장강도-인장변형 관계 특성을 고찰하였다. 또한 재질 및 제조방식이 상이한 3가지 지오그리드에 대해서는 일련의 광폭인장강도시험을 수행하여 실제 지오그리드 인장변형과 변형률계에 의해 측정된 인장변형을 비교하였다. 실험결과, 변형률계에 의해 측정된 인장변형률이 광폭인장강도시험기에 의해 측정된 실제변형률 보다 다소 큰 경향을 보이나 인장변형률이 3% 보다 작은 경우에는 측정방법에 따른 차이가 거의 없는 것으로 확인되었다.