• Smart Structures and Systems
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• 제20권6호
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• pp.759-767
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• 2017

Wear and aging associated damage is a severe problem for safety and maintenance of engineering structures. To acquire structural operational state and provide warning about different types of damage, research on damage identification has gained increasing popularity in recent years. Among various damage identification methods, the Lamb wave-based methods have shown promising suitability and potential for damage identification of plate-type structures. In this paper, a comprehensive study was presented to elaborate four remarkable aspects regarding the Lamb wave-based damage identification method for plate-type structures, including wave velocity, signal denoising, image reconstruction, and sensor layout. Conclusions and path forward were summarized and classified serving as a starting point for research and application in this area.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.505-508
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• 2008

When it grasps a total property losses and relationship of damage factors, there is possibility of reducing the natural disaster damage which is a yearly repeated. Also, checking and supply to vulnerability should be presupposed. This study aims to find out a damage factor vulnerability using a natural disaster database by Park et al(2007). And added 2005 year data to database. Total 10 damage factors are deaths(person, including missing person) injury(person), victims(person), building(thousand), vessel(thousand), cultivated land(thousand), public facilities(thousand), others(thousand), total property losses(thousand). We analyzed of correlation analysis, ratio, population, area, regional character etc for damage factors.

• 대한기계학회논문집
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• 제15권5호
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• pp.1455-1461
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• 1991

본 연구에서는 Kachanov의 재료손상(material damage)모델을 이용하여 새로운 수명예측식을 만들고, 이 수명예측식의 타당성을 조사하기 위하여, 최근에 발표된 크 립 수명과 기공분포와의 실험결과와 비교하였다.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.758-763
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• 2005

For international projects in general and the projects in the Gulf area in Particular, the most common cause of construction disputes and claims is construction delay. This paper will present different surveys to identify the causes of delay, the parties responsible, and how delay can be avoided. This paper will outline how these factors impact damage assessment and entitlement. Furthermore, a case study will be presented to show how the responsibility and damages due to delay are assessed and how entitlements are calculated.

• 한국환경생태학회지
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• 제37권6호
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• pp.439-449
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• 2023

본 연구는 우리나라 대형산불의 진화에 있어 임도(산림도로)의 역할을 검증하고자 하였다. 연구대상지는 그간 발생한 대형산불 중 도로밀도가 가장 높은 지역 중 하나인 강원특별자치도 강릉시에서 발생한 2023년 4월 산불피해지역을 대상으로 하였다. 산불피해지역 범위는 현장확인하였으며, 산불의 피해강도는 Sentinel-2 영상을 통해 분석하였다. 이후, 피해범위 및 강도와 산림도로의 관계를 살펴보았다. 전체 149.1ha의 산불피해지역에 쉽게 접근할 수 있는, 피해지역 경계로부터 50m 이내에 조성된 도로는 약 59.6km로, 인접지역을 포함한 산불피해지역의 도로밀도는 무려 168.9m/ha에 달했다. 도로에 의해 단절된 산림은 모두 83개소로 파편화되어 있었는데, 이들 산림은 모두 비산화에 의한 확산으로 판단할 수 있어, 도로가 산불의 차단선 역할을 하지 못했음이 확인되었다. 진화차량 접근의 용이성에 따른 피해정도를 살펴보기 위해 도로로부터의 거리별 피해강도 분포를 살펴본 결과, 낮은 강도의 피해를 입은 지역은 오히려 도로에서 75m이상 떨어진 곳에서 비율이 대폭 높아짐이 확인되었다. 진화인력의 접근 용이성에 따른 피해정도를 살펴보기 위해 해발고별 피해강도 분포를 살펴본 결과 약한 강도의 피해를 입은지역 비율은 해발고가 높아질수록 늘어난 반면, 강한 강도 이상의 피해지역은 반대로 해발고가 높아질수록 비율이 줄어들었다. 강릉시 난곡동 산불피해지역에서 산림내부 혹은 인접한 도로가 산불진화에 효과적이라는 데이터는 없는 것으로 확인되었다. 이상의 결과는 산림 내 임도밀도를 높이는 것이 산불진화에 효과적이라는 논리와 배치된다. 강릉시 난곡산불지역의 경우 현재 산림청이 주장하는 우리나라 임도밀도인 3.9m/ha에 비해 무려 43배나 높다.

• 산업기술연구
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• 제20권A호
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• pp.149-158
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• 2000

After measuring actual stress by two measurements(Dynamic Strain Meter, Histogram Recorder) on truss rail road bridge, we could perform time history analysis by 3-D beam element method on modelling bridge. And then, after analyzing bridge structure in static by 3-D modelling, we estimated degree of fatigue damage in main member, secondary member of tie zone, cutting area of base metal cross section for confirming the result. In case that the simulated stress is carried out on modeling bridge, most of those simulation mainly is performed by main members. But in real bridge fatigue damage problems generally caused by junctions, connections, joints in which especially local stress is activated. Therefore, in this paper actual stress on critical area was estimated through the analysis result by simulation. With this study, we can estimate the degree of fatigue damage from a safety point of view and comparative accuracy.

• 대한조선학회논문집
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• 제47권6호
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• pp.813-820
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• 2010

The spread mooring system for FPSO is developed to explore deep sea area, in which swell is dominant. It is known that the tension response of mooring lines in this sea area shows bimodal spectrum. Assuming normal distribution of tension profile and Rayleigh distribution of tension amplitude, the power spectral density function (PSD) of the mooring tension under the bimodal stationary random process is applied for the calculation of spectrum fatigue. Three popular methods, which are simple summation method, combined spectrum method and Jioa-Moan method, are used to combine fatigue damages from bimodal spectrum characteristics. Each damage value is compared with damage using Rainflow Cycle Counting (RCC) method which is believed to be close to exact solution. Vanmarcke' parameter and RMS(Root Mean Square) ratio are employed to assess relative damage variations between from RCC method and from three combination methods. Finally the most reliable fatigue damage combining method for spread mooring system is suggested.

• 지질공학
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• 제25권4호
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• pp.439-447
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• 2015

In this study, specific sections vulnerable to debris flow damage were selected, and a complete enumeration survey was performed for the sections with debris flow hazards. Based on this, the characteristics of the sections with debris flow hazards and the current status of actions against debris flow were examined, and an efficient installation plan for a debris flow damage prevention method that is required in the future was suggested. The results indicated that in the Route 56 section where the residential density is relatively higher between the two model survey sections, facilities for debris flow damage reduction were insufficient compared to those in the Route 6 section which is a mountain area. It is thought that several sites require urgent preparation of a facility for debris flow damage reduction. In addition, a numerical analysis showed that for debris barriers installed as a debris flow damage prevention method, distributed installation of a number of small-scale barriers facilities within a valley part was more effective than single installation of a large-scale debris barrier at the lower part of a valley.

• Smart Structures and Systems
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• 제32권1호
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• pp.49-59
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• 2023

A bridge transportation network supplies products from various source nodes to destination nodes through bridge structures in a target region. However, recent frequent earthquakes have caused damage to bridge structures, resulting in extreme direct damage to the target area as well as indirect damage to other lifeline structures. Therefore, in this study, a surrogate model-based comprehensive framework to estimate the seismic resilience of bridge transportation networks is proposed. For this purpose, total system travel time (TSTT) is introduced for accurate performance indicator of the bridge transportation network, and an artificial neural network (ANN)-based surrogate model is constructed to reduce traffic analysis time for high-dimensional TSTT computation. The proposed framework includes procedures for constructing an ANN-based surrogate model to accelerate network performance computation, as well as conventional procedures such as direct Monte Carlo simulation (MCS) calculation and bridge restoration calculation. To demonstrate the proposed framework, Pohang bridge transportation network is reconstructed based on geographic information system (GIS) data, and an ANN model is constructed with the damage states of the transportation network and TSTT using the representative earthquake epicenter in the target area. For obtaining the seismic resilience curve of the Pohang region, five epicenters are considered, with earthquake magnitudes 6.0 to 8.0, and the direct and indirect damages of the bridge transportation network are evaluated. Thus, it is concluded that the proposed surrogate model-based framework can efficiently evaluate the seismic resilience of a high-dimensional bridge transportation network, and also it can be used for decision-making to minimize damage.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.846-853
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• 2005

The whole death by disaster is totalized to 1,515 person from 1993 to 2004 year in our country. In this section life damages by landslide is totalized 357 people(about 24% of whole life damage). About 36 people are died by landslide(such as cutting area failure every year). Kangwon-do need a lot of interests and prevention because dangerous area that landslide occurrence is more than other area at summer localized downpour or thawing season and there is landslide occurrence possibility area more than other area. Kangwon-do area is higher than other area in natural disaster incidence and damage scale because topography and a lot of rainfalls by summer localized in Kangwon-Do than other area. In this study, dangerous area of landslide occurrence possibility is analyzed and compared Kangwon-Do with other areas in our country. as a result, every year we have experienced landslide occurrence and natural disaster. accordingly, we urgently need to prevent landslide occurrence and natural disaster by analy-zed source about landslide occurrence and condition of disaster in Kangwon-Do and suitable engineering method and construction work.