• Journal of the Korean Wood Science and Technology
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• 제36권4호
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• pp.84-92
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• 2008

강원도 양양 지역 산불 피해 소나무 목재의 피해 정도에 따른 해부 및 물리적 특성을 조사하였다. 피해 정도에 따라 수피의 탄화 깊이가 깊어지는 경향이 관찰되었으나 목질부까지 탄화가 진행되지는 않았으며 수지의 삼출정도에 차이를 보였다. 산불 피해목 변재의 생재함수율은 건전재보다 다소 낮게 나타났으나 심재의 경우에는 건전재보다 피해목이 다소 높게 나타났다. 생재밀도는 피해재 심재가 건전재 심재보다 다소 높게 나타났으며, 변재에서는 차이를 보이지 않았다. 형성층대를 관찰한 결과, 산불 피해를 강하게 입은 경우 형성층의 활동이 일어나지 않았고, 비교적 피해를 약하게 입은 경우에는 형성층의 활동이 관찰되었으나 세포분열 속도는 건전재보다 느렸다. 산불 피해를 강하게 입은 목재에서는 에피델리움세포와 방사조직의 세포벽이 짙게 염색되고 세포내에 과립형태의 물질이 관찰되었으며, 최외각 연륜 부위의 결정화도는 산불 피해재가 건전재보다 다소 높게 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.665-670
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• 1998

This study was carried out to investigate quantitatively the relationship between the degree of rebar corrosion and the strength of reinforced concrete beams. After producing equations for the relationship between both the tensile properties of rebars and bond properties and the corrosion percentage of rebars. Finite element analysis and bending tests were conducted for RC beams damaged by corrosion of tension main rebar. As a result, it was made that the strength of RC beams damged by corrosion could be practically simulated by FEM using experimentally determined material representing the bond properties and the mechanical properties of corroded rebars.

• 한국환경과학회지
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• 제25권1호
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• pp.127-134
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• 2016

This study is conducted to get current state of data collection and utilization of the trees damaged by pine wilt disease, and to efficiently collect and utilize of the trees damaged by the pine wilt disease and abandoned fumigation-treated trees at forecasts. The method to control pine wilt disease damaged area is mostly fumigation treatment system, and there is no collection and utilization of damaged trees because of absence of efficient collection system, lack of collection cost, and absence of policy, etc. A survey is conducted that asked about the satisfaction degree for the trees damaged by pine wilt disease collection and use divided into 6 topics. It was positively recognized that the need and problem of the trees damaged by pine wilt disease, and results and satisfaction of forestry mechanization while it was mostly negatively recognized that the policy satisfaction for prevention and collection, satisfaction of collection and use, collection and forestry mechanization, and satisfaction of foundation equipment for forestry mechanization, etc. As a result of path analysis, it is necessary to promote a high-tech forestry mechanization to improve satisfaction level of results and satisfaction of forestry mechanization for the trees damaged by pine wilt disease collection and utilization, it is also need to make an effort in various ways for improve satisfaction level of satisfaction of collection and utilization.

• Advances in concrete construction
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• 제5권5호
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• pp.539-561
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• 2017

In this study, the effects of initial damage of concrete columns on the post-repair performance of reinforced concrete (RC) columns strengthened with carbon-fiber-reinforced polymer (CFRP) composite are investigated experimentally. Four kinds of compression-damaged RC cylinders were reinforced using external CFRP composite wraps, and the stress-strain behavior of the composite/concrete system was investigated. These concrete cylinders were compressed to four pre-damaged states including low -level, medium -level, high -level and total damage states. The percentages of the stress levels of pre-damage were, respectively, 40, 60, 80, and 100% of that of the control RC cylinder. These damaged concrete cylinders simulate bridge piers or building columns subjected to different magnitudes of stress, or at various stages in long-term behavior. Experimental data, as well as a stress-strain model proposed for the behavior of damaged and undamaged concrete strengthened by external CFRP composite sheets are presented. The experimental data shows that external confinement of concrete by CFRP composite wrap significantly improves both compressive strength and ductility of concrete, though the improvement is inversely proportional to the initial degree of damage to the concrete. The failure modes of the composite/damaged concrete systems were examined to evaluate the benefit of this reinforcing methodology. Results predicted by the model showed very good agreement with those of the current experimental program.

• 한국해양학회지:바다
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• 제10권3호
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• pp.171-180
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• 2005

2004년 수마트라 지진에 의해 야기된 지진해일의 충격과 관련하여 태국 피해연안에서 "Tsunami impact on the coastal zone of Thailand"라는 제목의 야외답사가 3일간 수행되었다. 태국 안다만해 연안의 지진해일 피해지역은 피해정도에 따라 심한 피해 연안역, 중간 피해 연안역, 약한 피해 연안역으로 구분된다. 하구의 수로들은 넓어지고 해빈 모래는 침식되어 인근해역이나 배후지역에 재퇴적되었다. 답사는 심한 피해 연안역인 팡아(Phang Nga)주와 약한 피해 연안역인 푸켓 섬 등 대표지역의 총 12개 지점에서 수행되었다. 본고에서는 지진해일 이전과 이후의 위성자료와 현장답사 사진을 중심으로 지질해일이 태국의 연안역에 미친 지질학적 영향을 소개한다.

• Advances in concrete construction
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• 제9권4호
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• pp.413-421
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• 2020

For steel-concrete girders made composite using shear studs, initial damage on studs induced by weld defect, unexpected overloading, fatigue and others might degrade the service performance and even threaten the structural safety. This paper conducted a numerical study to investigate the static behavior of damaged stud shear connectors that were embedded in ultra high performance concrete (UHPC). Parameters included damage degree and damage location. The material nonlinear behavior was characterized by multi-linear stress-strain relationship and damage plasticity model. The results indicated that the shear strength was not sensitive to the damage degree when the damage occurred at 2/3d (d is the stud diameter) from the stud root. An increased stud area would be engaged in resisting shear force as the distance of damage location from stud root increased and the failure section becomes inclined, resulting in a less reduction in the shear strength and shear stiffness. The reduction factor was proposed to consider the degradation of the shear strength of the damaged stud. The reduction factor can be calculated using two approaches: a linear relationship and a square relationship with the damage degree corresponding to the shear strength dominated by the section area and the nominal diameter of the damaged stud. It was found that the proposed method is preferred to predict the shear strength of a stud with initial damage.

• 한국환경생태학회지
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• 제10권1호
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• pp.76-86
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• 1996

우리나라 중부지역에서 만성적인 환경오염 피해를 받고 있는 수목의 피해 정도와 지역별 범위를 알아보기 위해 독일가문비나무, 전나무, 소나무를 대상으로 본 연구를 실시하였다. 수목피해를 조기에 진단하기 위하여 피해도지수조사와 접촉각 측정을 실시한 결과 다음과 같은 결론을 얻을 수 있었다. 첫째, 서울과 인천 등의 대도심권을 중심으로 접촉각감소, 피해도지수의 증가와 같은 가시적인 피해와 생리적인 피해가 동시에 나타났다. 둘째, 전체 14개지역에서 다소의 차이는 있으나 모두 환경오염에 의한 수목의 피해를 모두 받고 있는 것으로 나타났다. 특히 인천을 비롯한 서해안 지역의 피해가 가중되고 있어 보다 관범위한 지역을 대상으로 체계적이고 지속적인 연구가 수행되어 이에 대한 대책이 이루어져야 할 것이다.

• 농업생명과학연구
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• 제43권6호
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• pp.19-27
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• 2009

본 연구는 산불 피해지에서의 임분구조 및 입지환경인자를 분석함으로서 이에 따른 산화 피해정도를 모형화하고 산화피해지의 피해목 처리에 따른 구성종의 종다양도 및 그 식생회복 형태를 구명하고자 하였다. 입지환경인자에 의한 산화피해율간의 관계를 정준상관 분석 및 로지스틱 회귀분석한 결과, 해발고 200m, 100m, 사면경사가 30도 이상인 입지의 임분밀도가 높은 소나무단순단층림이 산화 발생 피해율이 높은 것으로 추정되었다. 산화지 피해목 처리방법에 따른 식생회복 과정을 분석한 결과 피해목 존치보다는 피해목을 제거하는 것이 식생회복에 효과적이라 사료되었다. 따라서 산불피해지에 대한 식생회복을 위한 적절한 시업적 조치는 입지, 자생 수종 등을 복합적으로 고려하여야 할 것으로 사료되었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1998년도 제 23회 정기총회 및 추계학술발표회
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• pp.27-36
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• 1998

This paper presents a brief outline of dynamic stability of damaged ship in rough, beam wind and waves. The one degree-of-freedom, linear roll equation is adopted with the effects of damage fluid and external forces, but without the effect of sloshing. We evaluate the dynamic stability in terms of capizing probability based on energy balance mechanics and risk analysis , the method of which was proposed by Umeda [2] to the high speed crafts. As a result, we can predict the dynamic stability quantitatively according to sea state , operating and damage conditions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.13-16
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• 2005

This study is aimed to investigate the strength variation of fire-damaged reinforced concrete column by non-destructive test. It is studied to infer the recovery degree of residual strength of fire-damaged concrete. For measuring the surface hardness of RC columns. Schmidt hammer test is used. Testing is performed three-times: before fire test, directly after fire test and after 20 days.