• Title/Summary/Keyword: Side Friction

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A Study on Techniques of the construction and Space Structure of Nam-hea city walls (남해읍성의 공간구성과 축조기법에 관한 연구)

  • Kwon, Soon-Kang;Lee, Ho-Yeol
    • Journal of architectural history
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    • v.18 no.5
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    • pp.59-80
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    • 2009
  • The purpose of this study is to investigate the history, space structures, blueprint, and techniques of the construction of Nam-hea city walls. Nam-hea city walls were relocated in 1439 from Whagumhun-Sansung(火金峴山城) to the present site, nearby Nam-hea Um.(南海邑) The city walls were rebuilt after they were demolished during Japanese invasion on Korea in 1592 and their reconstruction was also done in 1757. At present, the city walls only partially remained due to the urbanization of the areas around them. A plane form of the City wall is a square, and the circumference os approximately 1.3km. According to the literature, the circumference of the castle walls is 2,876尺, the height is 13尺, and the width is 13尺 4寸. Hang-Kyo(鄕校). SaGikDan(社稷壇), YoeDan(厲壇), SunSo(船所) which is a harbor, as well as government and public offices such as Kaek-Sa(客舍) and Dong-Hun(東軒) existed inside the castle walls. Inside the castle walls were one well, five springs, one ditch, and one pond, and in the castle walls, four castle gates, three curved castle walls, and 590 battlements existed. The main government offices inside castle walls were composed of Kaek-Sa, Dong-Hun, and Han-Chung(鄕廳) their arrangements were as follows. Kaek-Sa was situated toward North. Dong-Hun was situated in the center of the west castle walls. The main roads were constructed to connect the North and South castle gate, and subsidiary roads were constructed to connect the East and West castle gate. The measurement used in the blueprint for castle wall was Pobaek-scale(布帛尺:1尺=46.66cm), and one side of it was 700尺. South and North gate were constructed in the center of South and North castle wall, and curved castle walls was situated there. One bastion was in the west of curved castle walls and two bastions were in the east of curved castle walls. The east gate was located in the five eighths of in the east castle wall. Two bastions were situated in the north, on bastion in the south, one bastion in the south, and four bastions in the west castle wall. The castle walls were constructed in the following order: construction of castle field, construction of castle foundation, construction of castle wall, and cover the castle foundation. The techniques used in the construction of the castle walls include timber pile(friction pile), replacement method by excavation.

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GEOTECHNICAL DESIGNS OF THE SHIP IMPACT PROTECTION SYSTEM FOR INCHEON BRIDGE

  • Choi, Sung-Min;Oh, Seung-Tak;Park, Sang-Il;Kim, Sung-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09c
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    • pp.72-77
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    • 2010
  • The Incheon Bridge, which was opened to the traffic in October 2009, is an 18.4 km long sea-crossing bridge connecting the Incheon International Airport with the expressway networks around the Seoul metropolitan area by way of Songdo District of Incheon City. This bridge is an integration of several special featured bridges and the major part of the bridge consists of cable-stayed spans. This marine cable-stayed bridge has a main span of 800 m wide to cross the vessel navigation channel in and out of the Incheon Port. In waterways where ship collision is anticipated, bridges shall be designed to resist ship impact forces, and/or, adequately protected by ship impact protection (SIP) systems. For the Incheon Bridge, large diameter circular dolphins as SIP were made at 44 locations of the both side of the main span around the piers of the cable-stayed bridge span. This world's largest dolphin-type SIP system protects the bridge against the collision with 100,000 DWT tanker navigating the channel with speed of 10 knots. Diameter of the dolphin is up to 25 m. Vessel collision risk was assessed by probability based analysis with AASHTO Method-II. The annual frequency of bridge collapse through the risk analysis for 71,370 cases of the impact scenario was less than $0.5{\times}10^{-4}$ and satisfies design requirements. The dolphin is the circular sheet pile structure filled with crushed rock and closed at the top with a robust concrete cap. The structural design was performed with numerical analyses of which constitutional model was verified by the physical model experiment using the geo-centrifugal testing equipment. 3D non-linear finite element models were used to analyze the structural response and energy-dissipating capability of dolphins which were deeply embedded in the seabed. The dolphin structure secures external stability and internal stability for ordinary loads such as wave and current pressure. Considering failure mechanism, stability assessment was performed for the strength limit state and service limit state of the dolphins. The friction angle of the crushed stone as a filling material was reduced to $38^{\circ}$ considering the possibility of contracting behavior as the impact.

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Experimental Investigation of Water Discharge Capability According to Shape of Sluice for Tidal Power Generation - I. Physical Experiment (조력발전용 수문 형상에 따른 통수성능에 관한 실험적 연구 - I. 수리모형실험)

  • Lee, Dal-Soo;Oh, Sang-Ho;Yi, Jin-Hak;Park, Woo-Sun;Cho, Hyu-Sang;Kim, Duk-Gu
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.1
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    • pp.73-80
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    • 2008
  • An hydraulic experiment was carried out in an open channel flume in order to improve the technique of designing shape of the sluice used for tidal power generation, which greatly affects the economical efficiency of the construction of a tidal power plant. To predict the influence of change in the major design parameters relating to the sluice shape on the water discharge capability of the sluice, it was necessary to perform a precise experiment that is discriminated to previous feasibility studies or design projects. For this purpose, by installing various flow straighteners and rectifying structures inside the water supply system and the rectifying tank, the flow in the flume was stabilized as tranquil as possible. In addition, the measuring instruments and the location of installing them were carefully determined so as to minimize the errors intervened during the measurement of water discharge and water level. The method of estimating head difference between upstream and downstream of the sluice was also developed by taking account of the head loss due to the friction at the bottom and side walls in the flume.

Experimental Assessment and Specimen Height Effect in Frost Heave Testing Apparatus (동상시험장비의 실험적 검증 및 시료크기의 영향에 관한 연구)

  • Jin, Hyunwoo;Ryu, Byunghyun;Lee, Jangguen
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.1
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    • pp.67-74
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    • 2019
  • Frost heave is one of the representative engineering characteristics in cold regions. In South Korea, which is located in seasonal frost area, structural damage caused by frost heave and thaw happens and the need for research on the frost heave is increasing. In this paper, newly developed transparent temperature-controllable cell is used to focus on the frost heave. Frost susceptible artificial soil is used to analyze water intake rate which is one of the important factors in frost susceptibility criteria. Frost heave rate and water intake rate have similar behavior after heave by freezing of pore water converges. O-ring installed in the upper pedestal to measure water intake rate generates side friction between the inner wall of the freezing cell and O-ring, thereby hindering frost heave. Therefore, the frost susceptibility criteria using the water intake rate is not reliable. It is appropriate to use frost heave rate which has similar behavior with water intake rate. Frost heave tests were performed under two different specimen heights. Overburden pressure, temperature gradient and dry unit weight were set under similar state. Based on laboratory testing results, frost heave is independent on the specimen height.

A Study on the Development of Load Transfer Curves of the Driven Steel Pipe Piles by Soil (타입강관말뚝의 토질별 하중전이곡선 도출에 관한 연구)

  • Lim, Jong-Seok;Choi, Yong-Kyu;Sim, Jong-Sun;Park, Jong-Hee
    • Journal of the Korean Geotechnical Society
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    • v.25 no.9
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    • pp.29-43
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    • 2009
  • As computational technologies have been developed, the load transfer analysis method using load transfer curves is widely performed. Now the load transfer analysis methods are widely used in our country. But most of the curves using in the analysis have been developed in foreign countries. In this study we gathered the data of in situ pile load tests on domestic nine sites in order to derive load transfer curves of driven steel pipe piles. Then we derived average lines of $f/f_{max}$-w/D curves for sandy and clayey soils respectively, which are expressed by hyperbolic function. And the results using these curves and the results using TZPile 2.0 (Analysis program of pile) were compared and analyzed with the results of pile load tests on domestic 3 sites in order to ascertain the applicability of the curves. The results show that the load-settlement relations using the curves in this study are more similar to the measured data and more conservative than those using TZPile 2.0.

Cases and Legal Issues For 119paramedics in Mental Emergency Situations (정신응급상황에서 119구급대원 대응사례와 법적쟁점)

  • Young Pyo Hong
    • The Korean Society of Law and Medicine
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    • v.25 no.1
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    • pp.87-115
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    • 2024
  • In Korea, exposure to stress has been accompanied by mental pain in the process of achieving many growth along with rapid development, various social problems, and the frequency of emergency hospitalization is increasing.. In the case of mentally ill patients, "unwanted hospitalization" is a problem, and police and 119 paramedics try to suppress the body of mentally ill patients, and many problems are exposed This is because the constituent requirements of the provisions of emergency hospitalization under the Mental Health and Welfare Act do not reflect reality, and each institution has a different position on one mentally ill person, and emergency hospitalization does not proceed smoothly or leads to friction between related organizations, and the safety of the mentally ill or others is not secured. Emergency hospitalization is defined as "a person who finds a person who is presumed to be mentally ill and is at high risk of harming his or her health or safety or others," and if the situation is so urgent that he or she cannot afford time to go through the hospitalization procedure to decide on his or her own hospitalization, he or she can request emergency hospitalization with the consent of a doctor and a police officer. In this case, 119 paramedics are escorted to a psychiatric institution. This provision of emergency hospitalization poses many problems in the process of transferring to psychiatric institutions. If a police officer or 119 paramedics in charge of practice use "physical force" during the emergency hospitalization process, side effects will inevitably occur, and professional negligence can be a problem. Specifically, when exercising physical force, the minimum necessary physical restraint based on laws and regulations and proportional principles is required, and the lack of the duty of care of 119 paramedics or police officers under the laws and regulations will eventually be resolved by applying other laws and regulations. Accordingly, it will be an opportunity for mentally ill patients to be transferred to psychiatric institutions in a safe environment by changing the subject of emergency hospitalization provisions under the Mental Health Welfare Act, defining and prescribing the use of physical protection guards as the enforcement regulations of the Mental Health Act, setting the duty of care for 119 paramedics and police officers, and creating an environment for transportation so that mentally ill patients can be treated safely.