• Smart Structures and Systems
• /
• v.25 no.3
• /
• pp.285-299
• /
• 2020

Long term structural health monitoring has gained wide attention among civil engineers in recent years due to the scale and severity of infrastructure deterioration. Establishing effective damage indicators and proposing enhanced monitoring methods are of great interests to the engineering practices. In the case of bridge health monitoring, long term structural vibration measurement has been acknowledged to be quite useful and utilized in the planning of maintenance works. Previous researches are majorly concentrated on linear time series models for the measurement, whereas nonlinear dependences among the measurement are not carefully considered. In this paper, a new bridge health monitoring method is proposed based on the use of long term vibration measurement. A combination of the fundamental ARMA model and copula theory is investigated for the first time in detecting bridge structural damages. The concept is applied to a real engineering practice in Japan. The efficiency and accuracy of the copula based damage indicator is analyzed and compared in different window sizes. The performance of the copula based indicator is discussed based on the damage detection rate between the intact structural condition and the damaged structural condition.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.35 no.4
• /
• pp.197-205
• /
• 2022

In this paper, a retaining wall system, developed using building Information modeling (BIM), is presented. Based on the information from a literature review, elementary technologies for the system were defined and developed. First, for the elementary technology, BIM libraries were constructed using standards and previous study results to achieve versatility and reusability. Second, methods for determining the quantity take-off (QTO) of a retaining wall were reviewed for an earth-work calculating system. Additionally, inverse distance weighting interpolation was used to generate topography. Finally, four formulas for calculating the QTO were proposed and devised for each element. After its development, the BIM system was analyzed and verified through comparison with a two-dimensional drawing-based QTO. The proposed system is deemed to be practical for determining the QTO of retaining walls and earth works. The contributions and limitations of the research are discussed in this paper.

• Journal of the Daesoon Academy of Sciences
• /
• v.21
• /
• pp.369-408
• /
• 2013

Korean reunification would be one of the greatest heaven-earth works by Gucheon Sangje in terms of the lasting paradise of the Later World. The Oseonwigi-gongsa describes what it will be around the Korean Peninsula. Furthermore, Haewon Sangsaeng is the very practical means in unifying the two Koreas. What are the effectiveness of Haewon Sangsaeng, regarding Korean reunification in dealing with the social science? This researcher has found out three main impacts as follows: (1) it deals deeply with the cause of the social conflicts, and it could provide the solutions towards the Later World, (2) it highlights the great values and the potential abilities of human, and (3) it widens the research areas up to the heave-earth-human Samgye. Dealing with Haewon Sangsaeng in the social science, researchers must consider the limit of the research, which are (1) the tenacity of researcher's goal and the extremity of the research, (2) the possibility of a fallacy in doing the social science, and (3) the paradox of knowledge. In conclusion, Haewon Sangsaeng has many fundamental and practical values when it comes to Korean reunification. First, it should be a very important virtue for the unification leadership and the Korean people. Second, it could heal the serious illness, rooted in the Korean War, and many internal conflicts between the right and the left ideologically. Finally, it also recover North Korean people's severe pain and grief under the long-term dictatorship, and the heterogeneity between the South and North Korean people for 60 years.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2004.11a
• /
• pp.317-322
• /
• 2004

As a construction project in urban area tends to be high-rise and huge, the importance of the project's underground work, in terms of the cost and the schedule, is gradually increasing. It's extremely significant to choose a proper filing method, at the stage of underground work. However, in piling work many change orders have been occurred since a piling method is experientially selected based on uncertain information and many earth factors to consider. It has effects on the cost and the schedule of the project. In this study, we have suggested a decision model for piling method that can be used to determine and verify the suitable piling method in design and pre-construction phase of a project. Based on historical data, a neural network model has already proven to be efficient. The tests of the model for selecting a suitable piling method have progressed exactly with the data of 150 piling works which were done room 2000 to 2004 in Korea. The optimization or the developed neural network model has progressed with the data for teaming. The validity of the neural network model has been verified.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.10 no.4
• /
• pp.142-152
• /
• 2007

Geotechnical information database, foundation of underground geographic information system in 2nd NGIS plan, had been developing by Ministry of Construction and Transportation since 2000. This database contains not only soil condition, such as depth, type and color of layer, and ground water level, but also engineering properties used for foundation design and construction, for instance, standard penetration test, compression test. But, it is difficult to apply this database for analyzing and designing geotechnical works, because report document is only offered. In this paper, we have developed web-based geospatial information system for the effective uses. First, underground cross-section model is generated by location, layer, and engineering properties of geotechnical information database at the realtime process. Second, earth volume, bearing capacity, and settlement is calculated and potentials of soft ground, liquefaction are evaluated through pre-defined empirical formula. This process is operated by web-based client. We wish to strengthen the application capacity through this system in construction planning and design works.

• Smart Structures and Systems
• /
• v.9 no.5
• /
• pp.393-410
• /
• 2012

Conventional geotechnical instrumentation techniques available for monitoring of slopes, especially soil-nailed slopes have limitations such as electromagnetic interference, low accuracy, poor longterm reliability and difficulty in mounting a series of strain sensors on a soil nail bar with a small-diameter. This paper presents a slope monitoring system based on fibre Bragg grating (FBG) sensing technology. This monitoring system is designed to perform long-term monitoring of slope movements, strains along soil nails, and other slope reinforcement elements. All these FBG sensors are fabricated and calibrated in laboratory and a trial of this monitoring system has been successfully conducted on a roadside slope in Hong Kong. As part of the slope stability improvement works, soil nails and a toe support soldier-pile wall were constructed. During the slope works, more than 100 FBG sensors were installed on a soil nail, a soldier pile, and an in- place inclinometer. The paper presents the layout and arrangement of the instruments as well as the installation procedures adopted. Monitoring data have been collected since March 2008. This trial has demonstrated the great potential of the optical fibre monitoring system for long-term monitoring of slope performance. The advantages of the slope monitoring system and experience gained in the field implementation are also discussed in the paper.

• Korean Journal of Construction Engineering and Management
• /
• v.19 no.1
• /
• pp.103-113
• /
• 2018

In this study, Construction work is mainly done outdoors, so earth works, reinforced concrete works, etc. are Non-Working Days to rainfall. In particular, changes in rainfall due to global warming have made air calculation more difficult. Therefore, when establishing the process plan, the change of the rainfall in the area should be identified and Non-Working Days should be calculated. In this study, the time of rainfall change point was identified using the meteorological 'observation' data from 1960 to 2016 in Incheon and RCP 4.5, 'weather forecast' data from 2018 to 2074, Year rainfall and seasonal rainfall. The results showed that rainfall changed point in 1972, 1988, 2013, 2038, 2050 and 2069. In particular, it has been found that non-working days due to rainfall has big changed point as of 2013, 2038 and 2069.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.2 s.18
• /
• pp.136-143
• /
• 2004

This study presents a risk management methodology using fuzzy theory for early construction stage and is focused on risk identification and risk analysis. This study identifies various risk factors associated with activities clearly construction stage, then establishes the Risk Breakdown Structure(RBS) by classifying the risks into the three groups; Common risks, risks for Earth works, and risks for Foundation works. The risk analysis method presented in this study is based on the RBS that has two levels such as upper level and lower level. The risk exposure of lower level risk factors is assessed by fuzzy inference. The weight of risks is estimated by fuzzy measure. Then, the estimated risk exposures and weights are aggregated to assess the risk exposure of upper level risks by Choquet fuzzy integral. The risk exposure of upper level risks determine the priority of risk factors in view of risk management. This study performs case study to validate the proposed method. The result of case study shows that the methodology suggested in this thesis would be utilized well in evaluating risk exposure.

• English & American cultural studies
• /
• v.16 no.2
• /
• pp.47-70
• /
• 2016

Under the inhumane oppression of imperialism, the Third World's political violence has been often represented as an immediate and explosive one with an instant, concentrated visibility. Yet the ecological and psychological exploitation of the Third-World countries by empires, as Rob Nixon insists, shows the relative invisibility of slow violence. This paper is to reveal this slow violence of the marginalized areas symbolized as the lowland. Although Arne Naess' deep ecology promotes the inherent worth of living beings regardless of their instrumental utility to human needs. this paper deals with three postcolonial ecological textbooks which criticize the white-centered deep ecology: Amitav Ghosh's The Glass Palace, Jhumpa Lahiri's The Lowland, and Barbara Kingsolver's The Poisonwood Bible. Through postcolonial critical study, this paper finds out that all these three works have some themes in common. First, these postcolonial works assume a shape of family saga which is parallel to the slow violence of ecological and psychological plundering of empires in the postcolonial countries. Second, like the mangroves which have a tenacious hold on life, these postcolonial people rather overcome the heterogenic challenge with the sturdy and tough mind than defeated. Third, the native people's ethics of earth functions as the stronghold for their respectable lifestyle in their indigenous historicity. Finally, as a big fat brother, the Americanized globalization or neoliberalism is warned as the neocolonialism which is often shown as the disguised pattern of greenwashing. Namely, the people's self-enhancement is always prior to the imperialistic development or neoliberalism in the postcolonial ecological texts which sharply contrast the native's life consciousness and the empire's development theory.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.5 no.2
• /
• pp.11-18
• /
• 1985

A row of bored piles has been used in several excavation works to retain the earth. This excavation bracing system has much effect on low-vibration and low-noise during construction. The system is also effective to provide protection to the adjacent existing ground and structures. For the purpose of establishment of a logical design method for the bored piles, first, a theoretical equation to estimate the resistance of piles is derived. Because arching action of soils between piles is considered in the equation, the characteristics of soils and the installation condition of piles would be considered logically from the beginning. Then a method is investigated to decide the interval ratio of piles. According to the method, the interval between piles can be decided from the information of the Peck's stability number, the coefficient of lateral earth pressure and the internal friction angle of soil. Finally, a design method is presented for the bored piles used for excavation work. In the presented design method, such factors as depth of excavation, pile diameter, interval between piles, pile length below bottom of excavation and pile stiffness, can be selected systematically.