• Smart Structures and Systems
• /
• 제15권3호
• /
• pp.555-576
• /
• 2015

The large number of long-span bridges constructed in China motivates the applications of structural health monitoring (SHM) technology. Many bridges have been equipped with sophisticated SHM systems in the mainland of China and in Hong Kong of China. Recently, SHM technology has been extended to field test systems. In this view, SHM can serve as a tool to develop the methods of life-cycle performance design, evaluation, maintenance and management of bridges; to develop new structural analysis methods through validation and feedback from SHM results; and to understand the behavior of bridges under natural and man-made disasters, rapidly assess the damage and loss of structures over large regions after disasters, e.g., earthquake, typhoon, flood, etc. It is hoped that combining analytical methods, numerical simulation, small-scale tests and accelerated durability tests with SHM could become the main engine driving the development of bridge engineering. This paper demonstrates the above viewpoint.

• Structural Engineering and Mechanics
• /
• 제19권3호
• /
• pp.261-279
• /
• 2005

The hot spot stress approach is usually adopted in the fatigue design and analysis of tubular welded joints. To apply the hot spot stress approach for fatigue evaluation of long span suspension bridges, the FEM is used to determine the hot spot stress of critical fatigue location. Using the local finite element models of the Tsing Ma Bridge, typical joints are developed and the stress concentration factors are determined. As a case for study, the calculated stress concentration factor is combined with the nominal representative stress block cycle to obtain the representative hot spot stress range cycle block under traffic loading from online health monitoring system. A comparison is made between the nominal stress approach and the hot spot stress approach for fatigue life evaluation of the Tsing Ma Bridge. The comparison result shows that the nominal stress approach cannot consider the most critical stress of the fatigue damage location and the hot spot stress approach is more appropriate for fatigue evaluation.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 B
• /
• pp.1382-1384
• /
• 2002

The flooded type battery is used for solar lighting system. Because the characteristic of flooded type battery is the short life time, the maintenance cost is high. So the using flooded type battery in this system is inappropriate. The valve regulated lead acid batter.(VRLA) is the maintenance free and cycle service purpose. This paper presents the development of control system and monitoring system to applied VRLA battery for maintenance free and long life time in system.

• 대한기계학회논문집A
• /
• 제40권12호
• /
• pp.1027-1035
• /
• 2016

내식성과 기계적 성능이 우수한 316L 스테인리스 강의 저주기 변형률제어 피로시험에서 3가지 변형률진폭과 3가지 변형률비의 조건이 피로수명에 미치는 효과를 분석하였다. 낮은 변형률범위에서 곡선이 거의 중첩되는 Masing 거동이 나타나고, 높은 변형률범위에서 비선형거동 응력범위가 서로 크게 벗어나는 non-Masing 거동과 함께 평균응력의 감소가 나타났다. 소성 변형률에너지를 이용하여 저주기 피로수명을 예측하고 non-Masing 거동을 고려한 수명예측 방법의 정확성 여부를 검토하였다. 각각의 변형률진폭과 변형률비의 조건에서 초기 수 사이클 동안 반복경화 현상 후 장시간동안 점진적으로 낮아져 연화하다가 파괴 되었다. 저사이클 피로수명을 정확히 예측하기 위해서는 변형률진폭에 따라 Masing 및 non-Masing 거동을 구분하고, 이를 반영한 수명예측식을 적용해야 함을 알았다.

• 한국터널지하공간학회 논문집
• /
• 제23권5호
• /
• pp.315-323
• /
• 2021

터널은 주·야간 모두 인공조명을 사용해야 되는 특성으로 인해 에너지 소비가 가장 많이 발생하는 도로 공간으로, 전기요금 절감 등을 위해 기존 터널조명 광원 대비 낮은 소비전력, 장수명의 장점을 갖는 LED램프로 교체 중에 있다. 터널구조물은 공용 중 부속시설 교체라는 일련의 중장기적이고 지속적인 과정이 수반되므로, 시설물 공용기간 동안의 생애주기비용을 고려해야 사회간접자본의 효율적인 활용을 기대할 수 있다. 따라서 본 연구에서 터널 조명광원을 고압나트륨램프에서 LED램프로 교체 시 LCC측면의 절감효과를 정량적으로 분석하였으며, 터널 조명 광원을 LED램프로 교체 시 램프의 수명증대에 의한 교체주기 감소 및 이로 인한 유지관리 비용 감소효과가 매우 큰 것으로 나타났다.

• 한국건설관리학회논문집
• /
• 제16권4호
• /
• pp.41-49
• /
• 2015

다중이용시설의 환기부문 에너지소비량이 전체 에너지소비에서 차지하는 비중은 약40%로서 상당히 크다. 환기설비분야의 에너지절약방안으로는 주동력원이자 주요에너지소비원인 전동기를 고효율 제품으로 교체하거나 인버터를 이용한 가변운전을 통하여 에너지를 절감시키는 방안이 있다. 그러나 이런 방안들을 도입하기 위해서는 기존설비보다 높은 초기투자비가 필요하므로 장기적인 관점에서의 경제성평가가 요구된다. 경제성평가 방법으로 생애주기동안 지출되는 모든 비용을 예측하는 LCCA(Life Cycle Cost Analysis)가 적절하지만 LCCA는 분석내용이 단순 비용절감측면에 치중되어 있어, 환경영향을 고려하지 못하는 한계가 있다. 환경영향을 분석하기 위한 방법으로 LCA(Life Cycle Assessment)있지만 이는 주로 건축물에만 사용되어왔고 또한 환경적인 측면만 치중하여 경제적은 측면을 고려하지 못하는 한계가 있다. 이에 본 연구에서는 LCCA 및 LCA를 이용해 경제적 측면 및 환경적 영향을 종합적으로 분석하여 다중이용시설 환기설비에 고효율 전동기 도입의 타당성 검토를 진행하고자 한다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.1134-1141
• /
• 2011

Costs have long since become a major issue in railway system analysis, attention is not limited to the acquisition costs alone, but encompasses all costs involved in the use and disposal of the systems. Concepts such as Life Cycle Cost(LCC), Costs Of Ownership(COO), or Total Ownership Cost(TOC) are more and more frequent in any document dealing with system analysis. Most of railway projects have applied this LCC Model to evaluate effectiveness of system acquisition cost. But these action of LCC model does not applied all the rest of system life cycle period due to the differences of its responsibility. This is why a study has been undertaken by the operation party to harmonize the most important aspects of the LCC model. This study focused on these and other objectives for introduction of method and needs for an action plan for maintenance actions involved relevant cost allocation.

• 한국CDE학회논문집
• /
• 제16권4호
• /
• pp.292-299
• /
• 2011

Han-ok has a long history and cultural traditions. It has green and healthy and culture but high construction costs, thermal insulation performance of residential and vulnerable to fires and have a weakness for maintenance. However, modernized resident housing, Han-ok is required to improve in terms of environmental aspect due to its weakness for insulating and inconvenience for modem era. Also Han-Ok's building is criticized as a huge dependence on subjective building experiences. This is pointed to be the biggest problem, Han-ok has. Traditionally it does not have a scientific and specific manual for construction. In this research, process simulation was adopted to develop Han-Ok's environmental improvements. In terms of LCC (Life Cycle Cost) aspect, however, Han-Ok's environmental characteristics are examined to suggest an appropriate Han-Ok construction method. Also the result of this research would be utilized to base the information database for efficient constructing and its management in new Han-Ok constructing industry.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.1623-1629
• /
• 2010

The high speed rolling stock system considerably belongs to a special industry which requires large-scale investment cost but the recovery term is long. Therefore, to guarantee risk and possibility of technological success in initial investment, tools concerned with various expecting methods like life cycle costs analysis and credibility management are used. In view of this characteristics, the cases on cost structure for HSR RS previously invested should be studied and the method to appropriately allocate the life cycle of each sub-system like arrangement unit, electric device, braking device, door and car body should be realized. Moreover, the environmental aspects of main manufacturer and parts supplier can be checked. This study, through the case study for HSR cost structure in introduction and operational stage of KTX, aims to seek for the method to adapt to environmental changes like EU railway industry of which object is to acquire global market competitiveness by integrating manufacturing and operation of RS and the regulation and operation of IRIS which is performed in Europe.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
• /
• pp.66-67
• /
• 2018

Large-scale construction projects require various license and technologies for the manufacturing and handling processes. Also, the whole life cycle business process management determines the success of the project. Then, the efficiency of the business conducted by stakeholders and their possessed technology should be enhanced in order to strengthen their competitive power. For this reason, many experts pointed out to focus on the improvement of the life cycle process and efficient management. Since it is very important to keep up-to-date data and utilize it for work during the long-term project to reflect changes in the large-scale project, the most important part of the project management in project is information change management. Therefore, the objective of this study is applying configuration management(CM) technique in order to managing change data generated for planning in early phase. The result of this research will certainly assist the large-scale project managers in the development of information change management system.