• Journal of the Korean Geotechnical Society
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• v.30 no.4
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• pp.35-45
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• 2014

Limit equilibrium methods of slope stability analysis have been widely adopted mainly due to their simplicity and applicability. However, the conventional methods may not give reliable and convincing results for various geological conditions such as nonhomogeneous and anisotropic soils. Also, they do not take into account soil slope history nor the initial state of stress, for example excavation or fill placement. In contrast to the limit equilibrium analysis, the analysis of deformation and stress distribution by finite element method can deal with the complex loading sequence and the growth of inelastic zone with time. This paper proposes a technique to determine the critical slip surface as well as to calculate the factor of safety for shallow failure on partially saturated soil slope. Based on the effective stress field in finite element analysis, all stresses are estimated at each Gaussian point of elements. The search strategy for a noncircular critical slip surface along weak points is appropriate for rainfall-induced shallow slope failure. The change of unit weight by seepage force has an effect on the horizontal and vertical displacements on the soil slope. The Drucker-Prager failure criterion was adopted for stress-strain relation to calculate coupling hydraulic and mechanical behavior of the partially saturated soil slope.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.235-246
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• 2003

Since the study of Lee et al.(1994) there have been some case studies on the set-up effect of driven piles in Korea country. However, comprehensive examination on the analyses of the set-up effect with various testing data has not been carried out. In particular, the analysis of the influence of soil type and pile shape on the set-up effect has not been reported. It is necessary to analyse the test results of production piles in order to apply the set-up effect of driven piles for the field engineering. In this study some test piling and analyses were performed to give basic information to the piling design as well as the research on the set-up effect in sandy soils. The analyses on the set-up effect were performed with the monitoring data obtained from the high-strain dynamic loading tests. It was shown that the set-up effect of driven piles was not only affected by soil type but also by soil formation history It turned out that the set-up effect in sandy soils was considerable one that should not be ignored in the field, and that the bearing capacity increase of pile is mainly caused by the increase of shaft resistance. It was shown that the set-up effect of closed pile was larger than that of opened pile in clayey soils, while the set-up effect of opened pile was larger than that of closed pile in sandy soils.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.94-105
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• 2013

Recently, the construction industry has been changed in such a way that the cost for bridge construction should be optimized or reduced. Therefore, bridges are required be cost-effective in terms of initial construction as well as in the maintenance during service stage. In order to reduce the cost for bridge construction, the Rahmen typed structure, in which the bridge components from superstructure to substructure are integral, has many advantages to reduce the size of structural members including girders, since the loadings from superstructure may be transferred to substructure through the connecting rebars such as stud, etc. This paper studied on the continuous Up and Down Prestressed Concrete (UD PSC) girder bridge in which the reinforced concrete pier cap is integral with the part of girders in superstructure. In previous studies, it is known that the structural behavior of continuous UD PSC girder bridge is quite different compared to the one of the bridges with conventional bearings or shoes to support the loading from girders. Nevertheless, it has hardly been studied about the structural behavior of bridge with UD PSC girder. Therefore, in this study, various dynamic behaviors of continuous UD PSC girder bridge with integral pier cap have been analyzed using numerical method. Furthermore, an equation to evaluate the impact factor is suggested for the UD PSC girder bridge which has two to three continuous spans.

• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.23-35
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• 2015

Nonlinear soil behavior before failure under dynamic loading is often implemented in a numerical analysis code by a mathematical fitting function model with Masing's rule. However, the model may show different behavior with an experimental results obtained from laboratory test in damping ratio corresponding secant shear modulus for a certain shear strain rage. The difference may come from an unique soil characteristics which is unable to implement by using the existing mathematical fitting model. As of now, several fitting models have been suggested to overcome the difference between model and real soil behavior but consequence of the difference in dynamic analysis is not reviewed yet. In this paper, the effect of the difference on site response was examined through nonlinear response history analysis. The analysis was verified and calibrated with well defined dynamic geotechnical centrifuge test. Site response analyses were performed with three mathematical fitting function models and compared with the centrifuge test results in prototype scale. The errors on peak ground acceleration between analysis and experiment getting increased as increasing the intensity of the input motion. In practical point of view, the analysis results of accuracy with the fitting model is not significant in low to mid input motion intensity.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.520-526
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• 2015

Reinforcing bar splices are inevitable in reinforced concrete structure. In these days, there are three main types of splices used in reinforced concrete construction site - lapped splice, mechanical splice and welded splice. Low cost, practicality in construction site, less time consuming and high performance make gas pressure welding become a favorable splice method. However, reinforcing bar splice experiences thermal loading history during the welding procedure. This may lead to the presence of residual stress in the vicinity of the splice which affects the fatigue life of the reinforcing bar. Therefore, residual stress analysis and tensile test of the gas pressure welded splice are carried out in order to verify the load bearing capacity of the gas pressure welded splice. The reinforcing bar used in this work is SD400, which is manufactured in accordance with KS D 3504. The results show that the residual stresses in welded splice is relatively small, thus not affecting the performance of the reinforcing bar. Moreover, the strength of the gas pressure welded splice is high enough for the development of yielding in the bar. As such, the reinforcing bar with gas pressure welded splice has enough capacity to behave as continuous bar.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.121-128
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• 2020

The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker-Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.

• Journal of the Society of Disaster Information
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• v.14 no.3
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• pp.379-386
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• 2018

Purpose: This study was to the fragility evaluation of I-shape curved beam structure subjected to strong ground motions including Gyeongju and Pohang earthquakes Method: In particular, to conduct the analytical model, ABAQUS and ANSYS platform was used in this study. Furthermore, the analytical model using 3D Finite Element Model (FEM) was validated, in comparison to the theoretical solutions at the location of 025L, 05L, and 0.75L in static loading condition. In addition, in order to evaluate the seismic fragility of the curved beam structure, 20 seismic ground motions were selected and Monte-Carlo Simulation was used for the empirical fragility evaluation from 0.2g to 1.5g. Result: It was interesting to find that the probability of the system failure was found at 0.2g, as using 190 MPa limit state and the probability of the failure using 390 MPa limit state was starting from 0.6g. Conclusion: This study showed the comparison of the theoretical solution with analytical solution on I-shaped curved beam structures and it was interesting to note that the system subjected to strong ground motions was sensitive to high frequency earthquake. Further, the seismic fragility corresponding to the curved beam shapes must be evaluated.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.331-337
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• 2022

In 2021, the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP), a U.N. advisory research institute, cited container loss as one of six sources of marine litters in shipping. The sinking of the X-P ress Pearl in May 2021 caused a catastrophic environmental pollution accident in which the loaded containers were moved to the shore, and the plastic pellets were loaded inside covered the coast of Sri Lanka. With this history, the International Maritime Organization (IMO) will discuss prevention and follow-up measures for container loss during ship voyages, as an agenda at the 8th Sub Committee on Carriage of Cargoes and Containers meeting in September 2022. To establish Korea's response direction at the IMO meeting, this study identified major causes of container loss accidents, and considered the response through analysis based on the accident investigation report and related professional data. As a result, it was found that the major cause of container loss during voyages was the enlargement of container ships, bad weather, and poor loading of containers. In particular, the need to prepare countermeasures for the deterioration of the operational safety of large container ships due to bad weather was identified. Additionally, integrated monitoring of the implementation of international conventions is required, for the safe sea transportation of container cargo. In particular, in terms of preservation of the marine environment, it is necessary to supplement the system for the recovery of lost containers. Finally, it was found that it is necessary to establish systems that can complement each other in the shipbuilding and shipping industries, in terms of shipbuilding as well as ship operation, to fundamentally prevent container loss accidents at sea. It is judged that it is difficult to resolve the various factors of container loss at sea during voyages, by responding from an individual perspective.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.107-113
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• 2017

To understand of the present state for temperature management of cold and frozen food transportation vehicles, we surveyed and measured the temperatures of eight transportation vehicles (including 3 small & medium and 5 large businesses) in Jeonbuk province, Korea. In the transportation vehicles of small & medium businesses, the mean temperature of cold and frozen foods was $8.35{\pm}5.72^{\circ}C$ and $-3.45{\pm}16.88^{\circ}C$; in large businesses, $3.92{\pm}1.44^{\circ}C$ and $-15.38{\pm}2.98^{\circ}C$, respectively. In the difference of temperature by the locations within transportation vehicles, the difference in each cold and frozen was $2.40{\pm}1.45^{\circ}C$ and $2.37{\pm}2.52^{\circ}C$, as a mean. But there was not statistically significant difference in locations between cold and frozen (p > 0.05). In the difference of surface temperatures on various foods before and after door opening during the loading, the temperatures of cold and frozen foods increased by $0.55^{\circ}C$ and $1.18^{\circ}C$, as means, respectively. The temperature of foods over time and placement of cold and frozen foods in transportation vehicles were not consistently maintained at optimal values in distribution. Therefore, the development of time-temperature history (TTH) system technology at the distribution level for cold and frozen foods is required.

• Journal of Korean Medical classics
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• v.9
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• pp.432-552
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• 1996

The influence of the four noted physicians of Geum-Won era(金元代) on the completion of the medicine in the Chosun dynasty(朝鮮朝) can be summarized as follows. 1. The four noted physicians of Geum-Won era were Yoo-Wan-So(劉完素), Jang-Jong-Jung(張從正), Lee-Go(李杲), Ju-Jin-Heung(朱震亨). 2. Yoo-Wan-So(劉完索) made his theory on the basic of Nae-Kyung("內經") and Sane-Han-Lon("傷寒論"), his idea of medicine was characterized in his books, for exemple, application of O-Oon-Yuk-Ki(五運六氣), Ju-Wha theory(主火論) and hang-hae-seng-je theory(亢害承制論). from his theory and method of study, many deviations of oriental medicine occurred. He made an effort for study of Nae-Kyung, which had been depressed for many years, on the contrary of the way old study that Nae-Kyung had been only explained or revised, he applied the theory of Nae-Kyung to clinical care. The theory of Yuk-Gi-Byung-Gi(六氣病機) and On-Yeul-Byung(溫熱病) had much influenced on his students and posterities, not to mention Jang-Ja-Wha and Ju-Jin-Heung, who were among the four noted physicians therefore he became the father of Yuk-Gi(六氣) and On-Yeul(溫熱) schools. 3. Jang-Jong-Jung(張從正) emulated Yoo-Wan-So as a model, and followed his Yuk-Gi-Chi-Byung(六氣致病) theory, but he insisted on the use of the chiaphoretic, the emetic and the paregoric to get rid of the causes, specially he insisted on the use of the paregoric, so they called him Gong-Ha-Pa(攻下派). He insisted on the theory that if we would strenthen ourselves we should use food, id get rid of cause, should use the paregoric, emetic and diaphoretic. Jang-Jong-Jung'S Gang-Sim-Wha(降心火) theory, which he improved Yoo-Wan-So's Han-Ryang(寒凉) theory influenced to originate Ju-Jin-Heung'S Ja-Eum-Gang-Wha(滋陰降火) theory. 4. Lee-Go(李杲) insisted on the theory that Bi-Wi(脾胃) played a loading role in the physiological function and pathological change, and that the internal disease was originated by the need of Gi(氣) came from the disorder of digestive organs, and that the causes of internal disease were the irregular meal, the overwork, and mental shock. Lee-Go made an effort for study about the struggle of Jung-Sa(正邪) and in the theory of the prescription he asserted the method of Seung-Yang-Bo-Gi(升陽補氣), but he also used the method of Go-Han-Gang-Wha(苦寒降火). 5. The authors of Eui-Hak-Jung-Jun("醫學正傳"), Eui-Hak-Ib-Moon("醫學入門"), and Man-Byung-Whoi-Choon("萬病回春") analyzed the medical theory of the four noted physicians and added their own experiences. They helped organizing existing complicated theories of the four noted physicians imported in our country, and affected the formation of medical science in the Choson dynasty largely. Eui-Hak-Jung-Jun("醫學正傳") was written by Woo-Dan(虞槫), in this book, he quoted the theories of Yoo-Wan-So, Jang-Jong-Jung, Lee-Go, Ju-Jin-Heung, especially, Ju-Jin-Heung was respected by him, it affected the writing of Eui-Lim-Choal-Yo("醫林撮要"). Eui-Hak-ib-Moon("醫學入門"), written by Lee-Chun(李杲), followed the medical science of Lee-Go and ju-jin-heung from the four noted physicians of Geum-Won era. Its characteristics of Taoism, idea of caring of health, and organization affected Dong-Eui-Bo-Kham("東醫寶鑑"). Gong-Jung-Hyun(龔延賢) wrote Man-Byung-Whoi-Choon("萬病回春") using the best part of the theories of Yoo-Wan-So, Jang-Jong-Jung, Lee-Go, Ju-Jin-Heung, this book affected Dong-Eui-Soo-Se-Bo-Won("東醫壽世保元") partly. 6. our medical science was developed from the experience of the treatment of disease obtained from human life, these medical knowledge was arranged and organized in Hyang-Yak-Jib-Sung-Bang("鄕藥集成方"), medical books imported from China was organized in Eui-Bang-Yoo-Chwi("醫方類聚"), which formed the base of medical development in the Chosun dynasty. 7. Eui-Lim-Choal-Yo("醫林撮要") was written by Jung-Kyung-Sun(鄭敬先) and revised by Yang-Yui-Soo(楊禮壽). It was written on the base of Woo-Dan's Eui-Jung-Jun, which compiled the medical science of the four noted physicians of Geum-Won era. It contained confusing theories of the four noted physicians of Geum-Won era and organized medical books of Myung era, therefore it completed the basic form of Byun-Geung-Non-Chi (辨證論治) influenced the writing of Dong-Eui-Bo-Kham("東醫寶鑑"). 8. Dong-Eui-Bo-Kham("東醫寶鑑") was written on the base of basic theory of Eum-Yang-O-Haeng(陰陽五行) and the theory of respondence of heaven and man(天人相應說) in Nae-Kyung. It contained several theories and knowledge, such as the theory of Essence(精), vitalforce(氣), and spirit(神) of Taoism, medical science of geum-won era, our original medical knowledge and experience. It had established the basic organization of our medical science and completed the Byun-Geung-Non-Chi (辨證論治). Dong-Eui-Bo-Kham developed medical science from simple medical treatment to protective medical science by caring of health. And it also discussed human cultivation and Huh-Joon's(許浚) own view of human life through the book. Dong-Eui-Bo-Kham adopted most part of Lee-Go(李杲) and Ju-Jin-Heung's(朱震亨) theory and new theory of "The kidney is the basis of apriority. The spleen is the basis of posterior", so it emphasized the role of spleen and kidney(脾腎) for Jang-Boo-Byung-Gi(臟腑病機). It contained Ju-Jin-Heung's theory of the cause and treatment of disease by colour or fatness of man(black or white, fat or thin). It also contained Ju-Jin-Heung's theory of "phlegm break out fever, fever break out palsy"(痰生熱 熱生風) and the theory of Sang-Wha(相火論). Dong-Eui-Bo-Kham contained Lee-Go's theory of Wha-Yu-Won-Bool-Yang-Lib (火與元氣不兩立論) quoted the theory of Bi-Wi(脾胃論) and the theory of Nae-Oi-Sang-Byun(內外傷辨). For the use of medicine, it followed the theory by Lee-Go. lt used Yoo-Wan-So'S theory of Oh-Gi-Kwa-Keug-Gae-Wi-Yul-Byung(五志過極皆爲熱病) for the treatment of hurt-spirit(傷神) because fever was considered as the cause of disease. It also used Jang-Jons-Jung's theory of Saeng-Keug-Je-Seung(生克制勝) for the treatment of mental disease. 9. Lee-je-ma's Dong-Eui-Soo-Se-Bo-Won("東醫壽世保元") adopted medical theories of Song-Won-Myung era and analyzed these theories using the physical constitutional theory of Sa-Sang-In(四象人). It added Dong-Mu's main idea to complete the theory and clinics of Sa-Sang-Eui-Hak(四象醫學). Lee-Je-Ma didn't quote the four noted physicians of Geum-Won era to discuss that the physical constitutional theory of disease and medicine from Tae-Eum-In(太陰人), So-Yang-In(少陽人), So-Eum-In(少陰人), and Tae-Yang-In(太陽人) was invented from their theories.